10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q

(Mark One)

☒ Quarterly Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

For the quarterly period ended March 31, 2024

or

☐	Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
	For the transition period from ______________ to ______________

Commission File Number 1-3548

ALLETE, Inc.

(Exact name of registrant as specified in its charter)

Minnesota	41-0418150
(State or other jurisdiction of incorporation or organization)	(IRS Employer Identification No.)

30 West Superior Street

Duluth, Minnesota 55802-2093

(Address of principal executive offices)

(Zip Code)

(218) 279-5000

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading symbol	Name of each exchange on which registered
Common Stock, without par value	ALE	New York Stock Exchange

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.   ☒ Yes   ☐ No

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).   ☒ Yes   ☐ No

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer”, “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

         Large Accelerated Filer    ☒             Accelerated Filer    ☐

         Non-Accelerated Filer    ☐         Smaller Reporting Company    ☐

                             Emerging Growth Company    ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).  ☐ Yes   ☒ No

Common Stock, without par value,

57,666,069 shares outstanding

as of March 31, 2024

Index

Definitions			3
Forward-Looking Statements			5
Part I.	Financial Information
	Item 1.	Consolidated Financial Statements - Unaudited	7
		Consolidated Balance Sheet	7
		Consolidated Statement of Income	8
		Consolidated Statement of Comprehensive Income	9
		Consolidated Statement of Cash Flows	10
		Consolidated Statement of Equity	11
		Notes to Consolidated Financial Statements	12
		Note 1. Operations and Significant Accounting Policies	12
		Note 2. Regulatory Matters	14
		Note 3. Equity Investments	17
		Note 4. Fair Value	17
		Note 5. Short-Term and Long-Term Debt	19
		Note 6. Commitments, Guarantees and Contingencies	20
		Note 7. Earnings Per Share and Common Stock	25
		Note 8. Income Tax Expense	26
		Note 9. Pension and Other Postretirement Benefit Plans	27
		Note 10. Business Segments	27
		Note 11. Subsequent Event – Agreement and Plan of Merger	29
	Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	30
		Comparison of the Three Months Ended	31
		Critical Accounting Policies	34
		Outlook	34
		Liquidity and Capital Resources	38
		Other	40
	Item 3.	Quantitative and Qualitative Disclosures about Market Risk	40
	Item 4.	Controls and Procedures	41
Part II.	Other Information
	Item 1.	Legal Proceedings	41
	Item 1A.	Risk Factors	41
	Item 2.	Unregistered Sales of Equity Securities and Use of Proceeds	42
	Item 3.	Defaults Upon Senior Securities	42
	Item 4.	Mine Safety Disclosures	43
	Item 5.	Other Information	43
	Item 6.	Exhibits	43
Signatures			44

ALLETE, Inc. First Quarter 2024 Form 10-Q

2

Definitions

The following abbreviations or acronyms are used in the text. References in this report to “we,” “us” and “our” are to ALLETE, Inc., and its subsidiaries, collectively.

Abbreviation or Acronym	Term
AFUDC	Allowance for Funds Used During Construction – the cost of both debt and equity funds used to finance regulated utility plant additions during construction periods
ALLETE	ALLETE, Inc.
ALLETE Clean Energy	ALLETE Clean Energy, Inc. and its subsidiaries
ALLETE Properties	ALLETE Properties, LLC and its subsidiaries
ALLETE South Wind	ALLETE South Wind, LLC
ALLETE Transmission Holdings	ALLETE Transmission Holdings, Inc.
Alloy Merger Sub	Alloy Merger Sub LLC, a Delaware limited liability company and wholly owned subsidiary of Alloy Parent.
Alloy Parent	Alloy Parent LLC, a Delaware limited liability company which, upon closing, will be jointly owned by a wholly owned subsidiary of Canada Pension Plan Investment Board and affiliates of investment vehicles affiliated with one or more funds, accounts, or other entities managed or advised by Global Infrastructure Management, LLC.
ATC	American Transmission Company LLC
BNI Energy	BNI Energy, Inc. and its subsidiary
Boswell	Boswell Energy Center
Caddo	ALLETE Clean Energy’s Caddo Wind Energy Facility
Cliffs	Cleveland-Cliffs Inc.
Company	ALLETE, Inc. and its subsidiaries
CSAPR	Cross-State Air Pollution Rule
Diamond Spring	ALLETE Clean Energy’s Diamond Spring Wind Energy Facility
ECO	Energy Conservation and Optimization Plan
EPA	United States Environmental Protection Agency
ESOP	Employee Stock Ownership Plan
FERC	Federal Energy Regulatory Commission
Form 10-K	ALLETE Annual Report on Form 10-K
Form 10-Q	ALLETE Quarterly Report on Form 10-Q
GAAP	Generally Accepted Accounting Principles in the United States of America
GHG	Greenhouse Gases
HVDC	High-Voltage Direct-Current
IBEW	International Brotherhood of Electrical Workers
Invest Direct	ALLETE’s Direct Stock Purchase and Dividend Reinvestment Plan
Item ___	Item ___ of this Form 10-Q
kV	Kilovolt(s)
kWh	Kilowatt-hour(s)
Laskin	Laskin Energy Center
Lampert Capital Markets	Lampert Capital Markets, Inc.
Merger	Pursuant to the Merger Agreement, on the terms and subject to the conditions set forth therein, Alloy Merger Sub will merge with and into ALLETE (the “Merger”), with ALLETE continuing as the surviving corporation in the Merger and becoming a subsidiary of Alloy Parent.
Merger Agreement	Agreement and Plan of Merger, dated as of May 5, 2024, by and among ALLETE, Alloy Parent, and Alloy Merger Sub.
Minnesota Power	An operating division of ALLETE, Inc.
Minnkota Power	Minnkota Power Cooperative, Inc.

ALLETE, Inc. First Quarter 2024 Form 10-Q

3

Abbreviation or Acronym	Term
MISO	Midcontinent Independent System Operator, Inc.
Moody’s	Moody’s Investors Service, Inc.
MPCA	Minnesota Pollution Control Agency
MPUC	Minnesota Public Utilities Commission
MW	Megawatt(s)
NAAQS	National Ambient Air Quality Standards
NDPSC	North Dakota Public Service Commission
New Energy	New Energy Equity LLC
Nippon Steel	Nippon Steel Corporation
Nobles 2	Nobles 2 Power Partners, LLC
NOX	Nitrogen Oxides
Northshore Mining	Northshore Mining Company, a wholly-owned subsidiary of Cleveland-Cliffs Inc.
Note ___	Note ___ to the Consolidated Financial Statements in this Form 10-Q
NPDES	National Pollutant Discharge Elimination System
NTEC	Nemadji Trail Energy Center
PPA / PSA	Power Purchase Agreement / Power Sales Agreement
PPACA	Patient Protection and Affordable Care Act of 2010
PSCW	Public Service Commission of Wisconsin
SEC	Securities and Exchange Commission
SO2	Sulfur Dioxide
Sofidel	The Sofidel Group
Square Butte	Square Butte Electric Cooperative, a North Dakota cooperative corporation
South Shore Energy	South Shore Energy, LLC
ST Paper	ST Paper LLC
SWL&P	Superior Water, Light and Power Company
Taconite Harbor	Taconite Harbor Energy Center
U.S.	United States of America
USS Corporation	United States Steel Corporation

ALLETE, Inc. First Quarter 2024 Form 10-Q

4

Forward-Looking Statements

Statements in this report that are not statements of historical facts are considered “forward-looking” and, accordingly, involve risks and uncertainties that could cause actual results to differ materially from those discussed. Although such forward-looking statements have been made in good faith and are based on reasonable assumptions, there can be no assurance that the expected results will be achieved. Any statements that express, or involve discussions as to, future expectations, risks, beliefs, plans, objectives, assumptions, events, uncertainties, financial performance, or growth strategies (often, but not always, through the use of words or phrases such as “anticipates,” “believes,” “estimates,” “expects,” “intends,” “plans,” “projects,” “likely,” “will continue,” “could,” “may,” “potential,” “target,” “outlook” or words of similar meaning) are not statements of historical facts and may be forward-looking.

In connection with the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, we are providing this cautionary statement to identify important factors that could cause our actual results to differ materially from those indicated in forward-looking statements made by or on behalf of ALLETE in this Form 10-Q, in presentations, on our website, in response to questions or otherwise. These statements are qualified in their entirety by reference to, and are accompanied by, the following important factors, in addition to any assumptions and other factors referred to specifically in connection with such forward-looking statements that could cause our actual results to differ materially from those indicated in the forward-looking statements:

•our ability to successfully implement our strategic objectives;

•global and domestic economic conditions affecting us or our customers;

•changes in and compliance with laws and regulations or changes in tax rates or policies;

•changes in rates of inflation or availability of key materials and supplies;

•the outcome of legal and administrative proceedings (whether civil or criminal) and settlements;

•weather conditions, natural disasters and pandemic diseases;

•our ability to access capital markets, bank financing and other financing sources;

•changes in interest rates and the performance of the financial markets;

•project delays or changes in project costs;

•changes in operating expenses and capital expenditures and our ability to raise revenues from our customers;

•the impacts of commodity prices on ALLETE and our customers;

•our ability to attract and retain qualified, skilled and experienced personnel;

•effects of emerging technology;

•war, acts of terrorism and cybersecurity attacks;

•our ability to manage expansion and integrate acquisitions;

•population growth rates and demographic patterns;

•wholesale power market conditions;

•federal and state regulatory and legislative actions that impact regulated utility economics, including our allowed rates of return, capital structure, ability to secure financing, industry and rate structure, acquisition and disposal of assets and facilities, operation and construction of plant facilities and utility infrastructure, recovery of purchased power, capital investments and other expenses, including present or prospective environmental matters;

•effects of competition, including competition for retail and wholesale customers;

•effects of restructuring initiatives in the electric industry;

•the impacts on our businesses of climate change and future regulation to restrict the emissions of GHG;

•effects of increased deployment of distributed low-carbon electricity generation resources;

•the impacts of laws and regulations related to renewable and distributed generation;

•pricing, availability and transportation of fuel and other commodities and the ability to recover the costs of such commodities;

•our current and potential industrial and municipal customers’ ability to execute announced expansion plans;

•real estate market conditions where our legacy Florida real estate investment is located may deteriorate;

•the success of efforts to realize value from, invest in, and develop new opportunities;

•the risk that Alloy Parent or ALLETE may be unable to obtain governmental and regulatory approvals required for the Merger, or that required governmental and regulatory approvals or agreements with other parties interested therein may delay the Merger, may subject the Merger to or impose adverse conditions or costs or may cause the parties to abandon the Merger; and

•that the announcement and pendency of the Merger, during which the Company is subject to certain operating restrictions, could have an adverse effect on the Company’s businesses, results of operations, financial condition or cash flows.

ALLETE, Inc. First Quarter 2024 Form 10-Q

5

Forward-Looking Statements (Continued)

Additional disclosures regarding factors that could cause our results or performance to differ from those anticipated by this report are discussed in Part I, Item 1A. Risk Factors of our 2023 Form 10-K. Any forward-looking statement speaks only as of the date on which such statement is made, and we undertake no obligation to update any forward-looking statement to reflect events or circumstances after the date on which that statement is made or to reflect the occurrence of unanticipated events. New factors emerge from time to time, and it is not possible for management to predict all of these factors, nor can it assess the impact of each of these factors on the businesses of ALLETE or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statement. Readers are urged to carefully review and consider the various disclosures made by ALLETE in this Form 10-Q and in other reports filed with the SEC that attempt to identify the risks and uncertainties that may affect ALLETE’s business.

ALLETE, Inc. First Quarter 2024 Form 10-Q

6

PART I.  FINANCIAL INFORMATION

ITEM 1.  CONSOLIDATED FINANCIAL STATEMENTS

ALLETE

CONSOLIDATED BALANCE SHEET

Unaudited

	March 31, 2024	December 31, 2023
Millions
Assets
Current Assets
Cash and Cash Equivalents	$32.0	$71.9
Accounts Receivable (Less Allowance of $1.7 and $1.6)	142.2	137.2
Inventories – Net	182.7	175.4
Prepayments and Other	76.3	83.6
Total Current Assets	433.2	468.1
Property, Plant and Equipment – Net	5,009.1	5,013.4
Regulatory Assets	409.0	425.4
Equity Investments	333.1	331.2
Goodwill and Intangible Assets – Net	155.4	155.4
Other Non-Current Assets	264.8	262.9
Total Assets	$6,604.6	$6,656.4
Liabilities, Redeemable Non-Controlling Interest and Equity
Liabilities
Current Liabilities
Accounts Payable	$84.2	$102.2
Accrued Taxes	62.9	51.0
Accrued Interest	16.3	21.1
Long-Term Debt Due Within One Year	17.2	111.4
Other	80.2	91.9
Total Current Liabilities	260.8	377.6
Long-Term Debt	1,772.4	1,679.9
Deferred Income Taxes	195.0	192.7
Regulatory Liabilities	564.0	574.0
Defined Benefit Pension and Other Postretirement Benefit Plans	135.4	160.8
Other Non-Current Liabilities	268.0	264.3
Total Liabilities	3,195.6	3,249.3
Commitments, Guarantees and Contingencies (Note 6)
Redeemable Non-Controlling Interest	0.5	0.5
Equity
ALLETE Equity
Common Stock Without Par Value, 80.0 Shares Authorized, 57.7 and 57.6 Shares Issued and Outstanding	1,807.4	1,803.7
Accumulated Other Comprehensive Loss	(20.9)	(20.5)
Retained Earnings	1,036.5	1,026.4
Total ALLETE Equity	2,823.0	2,809.6
Non-Controlling Interest in Subsidiaries	585.5	597.0
Total Equity	3,408.5	3,406.6
Total Liabilities, Redeemable Non-Controlling Interest and Equity	$6,604.6	$6,656.4

The accompanying notes are an integral part of these statements.

ALLETE, Inc. First Quarter 2024 Form 10-Q

7

ALLETE

CONSOLIDATED STATEMENT OF INCOME

Unaudited

	Three Months Ended
	March 31,
	2024	2023
Millions Except Per Share Amounts
Operating Revenue
Contracts with Customers – Utility	$338.3	$312.6
Contracts with Customers – Non-utility	63.7	251.0
Other – Non-utility	1.3	1.3
Total Operating Revenue	403.3	564.9
Operating Expenses
Fuel, Purchased Power and Gas – Utility	133.5	118.6
Transmission Services – Utility	22.7	20.1
Cost of Sales – Non-utility	24.4	210.5
Operating and Maintenance	91.7	85.7
Depreciation and Amortization	65.0	62.3
Taxes Other than Income Taxes	18.7	19.4
Total Operating Expenses	356.0	516.6
Operating Income	47.3	48.3
Other Income (Expense)
Interest Expense	(20.4)	(19.3)
Equity Earnings	5.5	6.0
Other	8.6	4.1
Total Other Expense	(6.3)	(9.2)
Income Before Income Taxes	41.0	39.1
Income Tax Expense	4.0	1.5
Net Income	37.0	37.6
Net Loss Attributable to Non-Controlling Interest	(13.7)	(20.6)
Net Income Attributable to ALLETE	$50.7	$58.2
Average Shares of Common Stock
Basic	57.6	57.3
Diluted	57.7	57.3
Basic Earnings Per Share of Common Stock	$0.88	$1.02
Diluted Earnings Per Share of Common Stock	$0.88	$1.02

The accompanying notes are an integral part of these statements.

ALLETE, Inc. First Quarter 2024 Form 10-Q

8

ALLETE

CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME

Unaudited

	Three Months Ended
	March 31,
	2024	2023
Millions
Net Income	$37.0	$37.6
Other Comprehensive Income (Loss)
Unrealized Gain on Securities
Net of Income Tax Expense of $– and $0.1	—	0.1
Defined Benefit Pension and Other Postretirement Benefit Plans
Net of Income Tax Expense of $0.1 and $–	(0.4)	—
Total Other Comprehensive Income (Loss)	(0.4)	0.1
Total Comprehensive Income	36.6	37.7
Net Loss Attributable to Non-Controlling Interest	(13.7)	(20.6)
Total Comprehensive Income Attributable to ALLETE	$50.3	$58.3

The accompanying notes are an integral part of these statements.

ALLETE, Inc. First Quarter 2024 Form 10-Q

9

ALLETE

CONSOLIDATED STATEMENT OF CASH FLOWS

Unaudited

	Three Months Ended
	March 31,
	2024	2023
Millions
Operating Activities
Net Income	$37.0	$37.6
Adjustments to Reconcile Net Income to Cash provided by (used in) Operating Activities:
AFUDC – Equity	(1.2)	(0.5)
Loss (Income) on Investments and Property, Plant and Equipment	(0.5)	0.4
Depreciation Expense	65.0	62.3
Amortization of PSAs	(1.3)	(1.3)
Amortization of Other Intangible Assets and Other Assets	1.6	1.9
Deferred Income Tax Benefit	(2.9)	(6.3)
Share-Based and ESOP Compensation Expense	1.7	0.8
Defined Benefit Pension and Other Postretirement Plan Benefit	(3.4)	(0.8)
Fuel Adjustment Clause	4.9	15.3
Bad Debt Expense	0.3	0.3
Provision for Interim Rate Refund	5.5	5.1
Changes in Operating Assets and Liabilities
Accounts Receivable	(5.5)	17.3
Inventories	(7.3)	109.0
Prepayments and Other	6.7	11.0
Accounts Payable	(10.4)	(10.7)
Other Current Liabilities	(19.8)	(142.2)
Cash Contributions to Defined Benefit Pension Plans	(25.0)	(6.5)
Changes in Regulatory and Other Non-Current Assets	9.1	(0.7)
Changes in Regulatory and Other Non-Current Liabilities	5.6	0.4
Cash provided by Operating Activities	60.1	92.4
Investing Activities
Proceeds from Sale of Available-for-sale Securities	1.4	—
Payments for Purchase of Available-for-sale Securities	(1.5)	—
Payments for Equity Method Investments	(1.6)	(0.8)
Additions to Property, Plant and Equipment	(60.6)	(70.0)
Other Investing Activities	1.5	(3.9)
Cash used in Investing Activities	(60.8)	(74.7)
Financing Activities
Proceeds from Issuance of Common Stock	2.0	3.3
Proceeds from Issuance of Short-Term and Long-Term Debt	156.0	238.5
Repayments of Short-Term and Long-Term Debt	(158.0)	(227.8)
Proceeds from Non-Controlling Interest in Subsidiaries – Net	2.7	6.7
Distributions to Non-Controlling Interest	(0.5)	(0.3)
Dividends on Common Stock	(40.6)	(38.8)
Other Financing Activities	—	0.1
Cash used in Financing Activities	(38.4)	(18.3)
Change in Cash, Cash Equivalents and Restricted Cash	(39.1)	(0.6)
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	79.4	40.2
Cash, Cash Equivalents and Restricted Cash at End of Period	$40.3	$39.6

The accompanying notes are an integral part of these statements.

ALLETE, Inc. First Quarter 2024 Form 10-Q

10

ALLETE

CONSOLIDATED STATEMENT OF EQUITY

Unaudited

	Three Months Ended
	March 31,
	2024	2023
Millions Except Per Share Amounts
Equity
Common Stock
Balance, Beginning of Period	$1,803.7	$1,781.5
Common Stock Issued	3.7	4.1
Balance, End of Period	1,807.4	1,785.6
Accumulated Other Comprehensive Loss
Balance, Beginning of Period	(20.5)	(24.4)
Other Comprehensive Income – Net of Income Taxes
Unrealized Gain on Debt Securities	—	0.1
Defined Benefit Pension and Other Postretirement Plans	(0.4)	—
Balance, End of Period	(20.9)	(24.3)
Retained Earnings
Balance, Beginning of Period	1,026.4	934.8
Net Income Attributable to ALLETE	50.7	58.2
Common Stock Dividends	(40.6)	(38.8)
Balance, End of Period	1,036.5	954.2
Non-Controlling Interest in Subsidiaries
Balance, Beginning of Period	597.0	656.4
Proceeds from Non-Controlling Interest in Subsidiaries – Net	—	6.7
Net Loss Attributable to Non-Controlling Interest	(11.0)	(20.6)
Distributions to Non-Controlling Interest	(0.5)	(0.3)
Balance, End of Period	585.5	642.2
Total Equity	$3,408.5	$3,357.7
Redeemable Non-Controlling Interest
Balance, Beginning of Period	$0.5	—
Proceeds from Non-Controlling Interest in Subsidiaries	2.7	—
Net Loss Attributable to Non-Controlling Interest	(2.7)	—
Total Redeemable Non-Controlling Interest	$0.5	—
Dividends Per Share of Common Stock	$0.705	$0.6775

The accompanying notes are an integral part of these statements.

ALLETE, Inc. First Quarter 2024 Form 10-Q

11

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

The accompanying unaudited Consolidated Financial Statements have been prepared in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X, and do not include all of the information and notes required by GAAP for complete financial statements pursuant to such rules and regulations. Similarly, the December 31, 2023, Consolidated Balance Sheet was derived from audited financial statements, but does not include all disclosures required by GAAP. The presentation of certain prior period amounts on the Consolidated Financial Statements have been adjusted for comparative purposes. In management’s opinion, these unaudited financial statements include all adjustments necessary for a fair statement of financial results. All adjustments are of a normal, recurring nature, except as otherwise disclosed. Operating results for the three months ended March 31, 2024, are not necessarily indicative of results that may be expected for any other interim period or for the year ending December 31, 2024. For further information, refer to the Consolidated Financial Statements and notes included in our 2023 Form 10-K.

NOTE 1. OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES

Subsequent Events. The Company performed an evaluation of subsequent events for potential recognition and disclosure through the date of the financial statements issuance.

On May 5, 2024, ALLETE entered into the Merger Agreement. (See Note 11. Subsequent Event – Agreement and Plan of Merger.)

Cash, Cash Equivalents and Restricted Cash. We consider all investments purchased with original maturities of three months or less to be cash equivalents. As of March 31, 2024, restricted cash amounts included in Prepayments and Other on the Consolidated Balance Sheet include collateral deposits required under an ALLETE Clean Energy loan. The restricted cash amounts included in Other Non-Current Assets represent collateral deposits required under an ALLETE Clean Energy loan agreement as well as PSAs. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheet that aggregate to the amounts presented in the Consolidated Statement of Cash Flows.

Cash, Cash Equivalents and Restricted Cash	March 31, 2024	December 31, 2023	March 31, 2023	December 31, 2022
Millions
Cash and Cash Equivalents	$32.0	$71.9	$29.9	$36.4
Restricted Cash included in Prepayments and Other	5.9	5.1	7.4	1.5
Restricted Cash included in Other Non-Current Assets	2.4	2.4	2.3	2.3
Cash, Cash Equivalents and Restricted Cash on the Consolidated Statement of Cash Flows	$40.3	$79.4	$39.6	$40.2

Inventories – Net. Inventories are stated at the lower of cost or net realizable value. Inventories in our Regulated Operations segment are carried at an average cost or first-in, first-out basis. Inventories in our ALLETE Clean Energy segment and Corporate and Other businesses are carried at an average cost, first-in, first-out or specific identification basis.

Inventories – Net	March 31, 2024	December 31, 2023
Millions
Fuel (a)	$30.2	$27.2
Materials and Supplies	119.0	115.7
Renewable Energy Facilities Under Development (b)	33.5	32.5
Total Inventories – Net	$182.7	$175.4

(a)    Fuel consists primarily of coal inventory at Minnesota Power.

(b)    Renewable Energy Facilities Under Development as of March 31, 2024, consists primarily of project costs related to renewable energy development projects at New Energy.

Goodwill. The aggregate carrying amount of goodwill was $154.9 million as of March 31, 2024 ($154.9 million as of December 31, 2023). There have been no changes to goodwill by reportable segment for the quarter and three months ended March 31, 2024.

ALLETE, Inc. First Quarter 2024 Form 10-Q

12

NOTE 1. OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES (Continued)

Other Non-Current Assets	March 31, 2024	December 31, 2023
Millions
Other Postretirement Benefit Plans	$104.6	$106.3
Contract Assets (a)	17.9	18.5
Operating Lease Right-of-use Assets	11.3	10.7
ALLETE Properties	10.7	10.8
Restricted Cash	2.4	2.4
Finance Lease Right-of-use Assets	2.0	2.1
Other	115.9	112.1
Total Other Non-Current Assets	$264.8	$262.9

(a)    Contract Assets consist of payments made to customers as an incentive to execute or extend service agreements. The payments are being amortized over the term of the respective agreements as a reduction to revenue.     

Other Current Liabilities	March 31, 2024	December 31, 2023
Millions
PSAs	$6.0	$6.0
Customer Deposits	5.7	7.4
Provision for Interim Rate Refund	5.5	—
Operating Lease Liabilities	3.1	3.0
Finance Lease Liabilities	0.4	0.4
Other	59.5	75.1
Total Other Current Liabilities	$80.2	$91.9

Other Non-Current Liabilities	March 31, 2024	December 31, 2023
Millions
Asset Retirement Obligation (a)	$206.1	$202.9
PSAs	19.5	20.9
Operating Lease Liabilities	8.3	7.7
Finance Lease Liabilities	1.5	1.6
Other	32.6	31.2
Total Other Non-Current Liabilities	$268.0	$264.3

(a)The asset retirement obligation is primarily related to our Regulated Operations and is funded through customer rates over the life of the related assets. Additionally, BNI Energy funds its obligation through its cost-plus coal supply agreements for which BNI Energy has recorded a receivable of $37.2 million in Other Non-Current Assets on the Consolidated Balance Sheet as of March 31, 2024 ($37.2 million as of December 31, 2023).

ALLETE, Inc. First Quarter 2024 Form 10-Q

13

NOTE 1. OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES (Continued)

	Three Months Ended
	March 31,
Other Income	2024	2023
Millions
Pension and Other Postretirement Benefit Plan Non-Service Credits (a)	$4.3	$2.0
Interest and Investment Income	1.9	1.1
AFUDC - Equity	1.2	0.5
Other	1.2	0.5
Total Other Income	$8.6	$4.1

(a)These are components of net periodic pension and other postretirement benefit cost other than service cost. (See Note 9. Pension and Other Postretirement Benefit Plans.)

	Three Months Ended
	March 31,
Supplemental Statement of Cash Flows Information	2024	2023
Millions
Cash Paid for Interest – Net of Amounts Capitalized	$25.7	$24.6
Noncash Investing and Financing Activities
Decrease in Accounts Payable for Capital Additions to Property, Plant and Equipment	$(5.9)	$(7.1)
Capitalized Asset Retirement Costs	$2.2	$2.4
AFUDC–Equity	$1.2	$0.5

New Accounting Pronouncements and Disclosure Rules.

SEC Climate-related Disclosures Rule. On March 6, 2024, the SEC issued the final rules regarding the enhancement and standardization of climate-related disclosures for investors (Rule). The Rule requires registrants to provide certain climate-related information in their annual reports and registration statements. These requirements include disclosing climate-related risks that materially affect or are reasonably likely to materially affect a registrant’s business strategy, results of operations, or financial condition as well as certain disclosures related to greenhouse-gas emissions, and the effects of severe weather events and other natural conditions. The disclosure requirements will begin phasing in for annual periods beginning in 2025. The Company is evaluating the final rule to determine its impact on the Company’s disclosures. The Rule is currently being challenged before the U.S. Court of Appeals, and the SEC issued a voluntary stay of the Rule on April 4, 2024, pending judicial review.

There are no other new accounting pronouncements or rules that we anticipate having a material effect on the presentation of ALLETE’s consolidated financial statements.

NOTE 2. REGULATORY MATTERS

Regulatory matters are summarized in Note 4. Regulatory Matters to the Consolidated Financial Statements in our 2023 Form 10-K, with additional disclosure provided in the following paragraphs.

Electric Rates. Entities within our Regulated Operations segment file for periodic rate revisions with the MPUC, PSCW or FERC. As authorized by the MPUC, Minnesota Power also recognizes revenue under cost recovery riders for transmission, renewable, and environmental investments and expenditures. Revenue from cost recovery riders was $8.3 million for the three months ended March 31, 2024 ($16.4 million for the three months ended March 31, 2023).

ALLETE, Inc. First Quarter 2024 Form 10-Q

14

NOTE 2. REGULATORY MATTERS (Continued)

2024 Minnesota General Rate Case. On November 1, 2023, Minnesota Power filed a retail rate increase request with the MPUC seeking an average increase of approximately 12.00 percent for retail customers, net of rider revenue incorporated into base rates. The rate filing seeks a return on equity of 10.30 percent and a 53.00 percent equity ratio. On an annualized basis, the requested final rate increase would generate approximately $89 million in additional revenue. In separate orders dated December 19, 2023, the MPUC accepted the filing as complete and approved an annual interim rate increase of approximately $64 million, net of rider revenue, beginning January 1, 2024, subject to refund.

On May 3, 2024, Minnesota Power entered into a settlement agreement with the Minnesota Department of Commerce, Minnesota Office of the Attorney General, Residential Utilities Division, and Large Power Intervenors to settle the retail rate increase request. The settlement agreement is subject to approval by the MPUC. As part of the settlement agreement, the parties have agreed on all issues, including an overall rate increase of $33.97 million, net of rider revenue and amounts transferring to the fuel adjustment clause, a return on equity of 9.78 percent, all non-financial items and cost allocation. As a result of the settlement, Minnesota Power recorded a reserve for an interim rate refund of $5.5 million pre-tax as of March 31, 2024, which is subject to MPUC approval of the settlement agreement and Minnesota Power’s refund calculation.

2022 Minnesota General Rate Case. Minnesota Power is appealing with the Minnesota Court of Appeals (Court) specific aspects of the MPUC’s February 2023 and May 2023 rate case orders for the ratemaking treatment of Taconite Harbor and Minnesota Power’s prepaid pension asset. Oral arguments on the appeal are expected to be heard by the Court in the second quarter of 2024 with a decision expected in the third quarter of 2024. We are unable to predict the outcome of this proceeding.

2024 Wisconsin General Rate Case. On March 29, 2024, SWL&P filed a rate increase request for its electric, gas and water utilities with the PSCW. The filing seeks an overall return on equity of 10.00 percent and a 55.00 percent equity ratio. On an annualized basis, the requested change would increase rates by approximately 5.90 percent for retail customers and generate an estimated $7.3 million of additional revenue. The change to SWL&P customers’ rates will be determined by the PSCW later this year. Any rate adjustments are anticipated to become effective in January 2025.

Transmission Cost Recovery Rider. Minnesota Power has an approved cost recovery rider in place to charge retail customers on a current basis for certain transmission investments and expenditures, including a return on the capital invested. Current customer billing rates are based on an MPUC order dated December 19, 2023, which provisionally approved Minnesota Power’s latest transmission factor filing submitted on October 24, 2023. Updated billing rates were included on customer bills starting in the first quarter of 2024, and the MPUC approved Minnesota Power’s transmission factor filing with no changes in an order dated March 5, 2024.

Renewable Cost Recovery Rider. Minnesota Power has an approved cost recovery rider in place to charge retail customers on a current basis for the costs of certain renewable investments and expenditures, including a return on the capital invested. Current customer billing rates for the renewable cost recovery rider were approved by the MPUC in an order dated October 3, 2023. On March 27, 2024, Minnesota Power submitted its latest renewable factor filing. If the filing is approved, Minnesota Power would be authorized to include updated billing rates on customer bills beginning October 1, 2024.

Solar Cost Recovery Rider. Minnesota Power has an approved cost recovery rider in place to charge retail customers on a current basis for solar costs related to investments and expenditures for meeting the state of Minnesota’s solar energy standard. Current customer billing rates were approved by the MPUC in an order dated December 26, 2023. Updated billing rates were included on customer bills starting in the first quarter of 2024.

Fuel Adjustment Clause. Minnesota Power incurred lower fuel and purchased power costs in 2023 than those factored in its fuel adjustment forecast filed in May 2022 for 2023, which resulted in the recognition of an approximately $13 million regulatory liability as of March 31, 2024, and December 31, 2023. Minnesota Power requested to refund the regulatory liability beginning in the third quarter of 2024 as part of its annual true-up filing submitted to the MPUC on March 1, 2024.

ALLETE, Inc. First Quarter 2024 Form 10-Q

15

NOTE 2. REGULATORY MATTERS (Continued)

Energy Conservation and Optimization (ECO) Plan. On April 1, 2024, Minnesota Power submitted its 2023 ECO annual filing (formerly the Conservation Improvement Plan) detailing Minnesota Power’s ECO plan results and requesting a financial incentive of $2.2 million, which will be recognized upon approval by the MPUC. In 2023, a financial incentive of $2.2 million was recognized in the third quarter upon approval by the MPUC of the 2022 ECO annual filing. The financial incentives are recognized in the period in which the MPUC approves the filing.

Regulatory Assets and Liabilities. Our regulated utility operations are subject to accounting standards for the effects of certain types of regulation. Regulatory assets represent incurred costs that have been deferred as they are probable for recovery in customer rates. Regulatory liabilities represent obligations to make refunds to customers and amounts collected in rates for which the related costs have not yet been incurred. The Company assesses quarterly whether regulatory assets and liabilities meet the criteria for probability of future recovery or deferral. The recovery, refund or credit to rates for these regulatory assets and liabilities will occur over the periods either specified by the applicable regulatory authority or over the corresponding period related to the asset or liability.

Regulatory Assets and Liabilities	March 31, 2024	December 31, 2023
Millions
Current Regulatory Assets (a)
Fuel Adjustment Clause	$8.1	$8.7
Other	0.6	0.6
Total Current Regulatory Assets	$8.7	$9.3
Non-Current Regulatory Assets
Defined Benefit Pension and Other Postretirement Plans	$217.3	$218.6
Income Taxes	85.1	88.1
Asset Retirement Obligations	38.3	37.7
Cost Recovery Riders	27.6	33.8
Taconite Harbor	18.3	20.9
Manufactured Gas Plant	13.1	13.2
PPACA Income Tax Deferral	3.9	3.9
Fuel Adjustment Clause	2.1	5.0
Other	3.3	4.2
Total Non-Current Regulatory Assets	$409.0	$425.4
Current Regulatory Liabilities (b)
Fuel Adjustment Clause	$9.0	—
Provision for Interim Rate Refund	5.5	—
Transmission Formula Rates Refund	1.0	$1.5
Other	1.6	2.4
Total Current Regulatory Liabilities	$17.1	$3.9
Non-Current Regulatory Liabilities
Income Taxes	$302.3	$310.0
Wholesale and Retail Contra AFUDC	77.3	78.0
Plant Removal Obligations	69.3	67.0
Defined Benefit Pension and Other Postretirement Benefit Plans	45.5	48.6
Non-Jurisdictional Land Sales	35.1	30.2
Investment Tax Credits	13.5	13.6
Fuel Adjustment Clause	8.2	15.5
Boswell Units 1 and 2 Net Plant and Equipment	6.7	6.7
Other	6.1	4.4
Total Non-Current Regulatory Liabilities	$564.0	$574.0

(a)Current regulatory assets are presented within Prepayments and Other on the Consolidated Balance Sheet.

(b)Current regulatory liabilities are presented within Other Current Liabilities on the Consolidated Balance Sheet.

ALLETE, Inc. First Quarter 2024 Form 10-Q

16

NOTE 3. EQUITY INVESTMENTS

Investment in ATC. Our wholly-owned subsidiary, ALLETE Transmission Holdings, owns approximately 8 percent of ATC, a Wisconsin-based utility that owns and maintains electric transmission assets in portions of Wisconsin, Michigan, Minnesota and Illinois. We account for our investment in ATC under the equity method of accounting.

ALLETE’s Investment in ATC
Millions
Equity Investment Balance as of December 31, 2023	$179.7
Cash Investments	1.6
Equity in ATC Earnings	5.7
Distributed ATC Earnings	(4.6)
Amortization of the Remeasurement of Deferred Income Taxes	0.3
Equity Investment Balance as of March 31, 2024	$182.7

ATC’s authorized return on equity was 10.02 percent, or 10.52 percent including an incentive adder for participation in a regional transmission organization, based on a 2020 FERC order which is subject to various outstanding legal challenges related to the return on equity calculation and refund period ordered by the FERC. In August 2022, the U.S. Court of Appeals for the District of Columbia Circuit vacated and remanded the 2020 FERC order back to FERC. We cannot predict the return on equity the FERC will ultimately authorize in the remanded proceeding.

In addition, the FERC issued a Notice of Proposed Rulemaking in 2021 proposing to limit the 0.50 percent incentive adder for participation in a regional transmission organization to only the first three years of membership in such an organization. If this proposal is adopted, our equity in earnings from ATC would be reduced by approximately $1 million pre-tax annually.

Investment in Nobles 2. Our subsidiary, ALLETE South Wind, owns 49 percent of Nobles 2, the entity that owns and operates a 250 MW wind energy facility in southwestern Minnesota pursuant to a 20-year PPA with Minnesota Power. We account for our investment in Nobles 2 under the equity method of accounting.

ALLETE’s Investment in Nobles 2
Millions
Equity Investment Balance as of December 31, 2023	$151.5
Equity in Nobles 2 Earnings (a)	(0.2)
Distributed Nobles 2 Earnings	(0.9)
Equity Investment Balance as of March 31, 2024	$150.4

(a)The Company also recorded earnings from net loss attributable to non-controlling interest of $3.0 million related to its investment in Nobles 2.

NOTE 4. FAIR VALUE

Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We utilize market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs can be readily observable, market corroborated or generally unobservable. We primarily apply the market approach for recurring fair value measurements and endeavor to utilize the best available information. Accordingly, we utilize valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. These inputs, which are used to measure fair value, are prioritized through the fair value hierarchy. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). Descriptions of the three levels of the fair value hierarchy are discussed in Note 7. Fair Value to the Consolidated Financial Statements in our 2023 Form 10-K.

ALLETE, Inc. First Quarter 2024 Form 10-Q

17

NOTE 4. FAIR VALUE (Continued)

The following tables set forth, by level within the fair value hierarchy, our assets and liabilities that were accounted for at fair value on a recurring basis as of March 31, 2024, and December 31, 2023. Each asset and liability is classified based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, which may affect the valuation of these assets and liabilities and their placement within the fair value hierarchy levels. The estimated fair value of Cash and Cash Equivalents on the Consolidated Balance Sheet approximates the carrying amount and therefore is excluded from the recurring fair value measures in the following tables.

	Fair Value as of March 31, 2024
Recurring Fair Value Measures	Level 1	Level 2	Level 3	Total
Millions
Assets
Investments (a)
Available-for-sale – Equity Securities	$8.6	—	—	$8.6
Available-for-sale – Corporate and Governmental Debt Securities (b)	—	$6.5	—	6.5
Cash Equivalents	6.0	—	—	6.0
Total Fair Value of Assets	$14.6	$6.5	—	$21.1
Liabilities
Deferred Compensation (c)	—	$18.1	—	$18.1
Total Fair Value of Liabilities	—	$18.1	—	$18.1
	Fair Value as of December 31, 2023
Recurring Fair Value Measures	Level 1	Level 2	Level 3	Total
Millions
Assets
Investments (a)
Available-for-sale – Equity Securities	$8.7	—	—	$8.7
Available-for-sale – Corporate and Governmental Debt Securities	—	$6.0	—	6.0
Cash Equivalents	5.8	—	—	5.8
Total Fair Value of Assets	$14.5	$6.0	—	$20.5
Liabilities
Deferred Compensation (c)	—	$16.5	—	$16.5
Total Fair Value of Liabilities	—	$16.5	—	$16.5

(a)Included in Other Non-Current Assets on the Consolidated Balance Sheet.

(b)As of March 31, 2024, the aggregate amount of available-for-sale corporate and governmental debt securities maturing in one year or less was $1.7 million, in one year to less than three years was $2.7 million, in three years to less than five years was $1.6 million and in five or more years was $0.5 million.

(c)Included in Other Non-Current Liabilities on the Consolidated Balance Sheet.

Fair Value of Financial Instruments. With the exception of the item listed in the following table, the estimated fair value of all financial instruments approximates the carrying amount. The fair value of the item listed in the following table was based on quoted market prices for the same or similar instruments (Level 2).

Financial Instruments	Carrying Amount	Fair Value
Millions
Short-Term and Long-Term Debt (a)
March 31, 2024	$1,797.3	$1,646.8
December 31, 2023	$1,799.4	$1,670.6

(a)Excludes unamortized debt issuance costs.

ALLETE, Inc. First Quarter 2024 Form 10-Q

18

NOTE 4. FAIR VALUE (Continued)

Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis. Non-financial assets such as equity method investments, land inventory, and property, plant and equipment are measured at fair value when there is an indicator of impairment and recorded at fair value only when an impairment is recognized. For the three months ended March 31, 2024, and the year ended December 31, 2023, there were no indicators of impairment for these non-financial assets.

We continue to monitor changes in the broader energy markets along with wind resource expectations that could indicate impairment at ALLETE Clean Energy wind energy facilities upon contract expirations or for facilities without long-term contracts for their entire output. A continued decline or volatility in energy prices or lower wind resource expectations could result in a future impairment.

NOTE 5. SHORT-TERM AND LONG-TERM DEBT

The following tables present the Company’s short-term and long-term debt as of March 31, 2024, and December 31, 2023:

March 31, 2024	Principal	Unamortized Debt Issuance Costs	Total
Millions
Short-Term Debt	$17.2	—	$17.2
Long-Term Debt	1,780.1	$(7.7)	1,772.4
Total Debt	$1,797.3	$(7.7)	$1,789.6

December 31, 2023	Principal	Unamortized Debt Issuance Costs	Total
Millions
Short-Term Debt	$111.5	$(0.1)	$111.4
Long-Term Debt	1,687.9	(8.0)	1,679.9
Total Debt	$1,799.4	$(8.1)	$1,791.3

We had $19.4 million outstanding in standby letters of credit and $94.0 million outstanding draws under our lines of credit as of March 31, 2024 ($19.4 million in standby letters of credit and $34.1 million outstanding draws as of December 31, 2023). We also have standby letters of credit outstanding under other letter of credit facilities. (See Note 6. Commitments, Guarantees and Contingencies.)

On April 23, 2024, ALLETE issued $100 million of its First Mortgage Bonds (Bonds) to certain institutional buyers in the private placement market. The Bonds, which bear interest at 5.72 percent, will mature in April 2039 and pay interest semi-annually in April and October of each year, commencing on October 30, 2024. ALLETE has the option to prepay all or a portion of the Bonds at its discretion, subject to a make-whole provision. The Bonds are subject to additional terms and conditions which are customary for these types of transactions. Proceeds from the sale of the Bonds were used to refinance existing indebtedness and for general corporate purposes. The Bonds were sold in reliance on an exemption from registration under Section 4(a)(2) of the Securities Act of 1933, as amended, to institutional accredited investors.

Financial Covenants. Our long-term debt arrangements contain customary covenants. In addition, our lines of credit and letters of credit supporting certain long-term debt arrangements contain financial covenants. Our compliance with financial covenants is not dependent on debt ratings. The most restrictive financial covenant requires ALLETE to maintain a ratio of indebtedness to total capitalization (as the amounts are calculated in accordance with the respective long-term debt arrangements) of less than or equal to 0.65 to 1.00, measured quarterly. As of March 31, 2024, our ratio was approximately 0.36 to 1.00. Failure to meet this covenant would give rise to an event of default if not cured after notice from the lender, in which event ALLETE may need to pursue alternative sources of funding. Some of ALLETE’s debt arrangements contain “cross-default” provisions that would result in an event of default if there is a failure under other financing arrangements to meet payment terms or to observe other covenants that would result in an acceleration of payments due. ALLETE has no significant restrictions on its ability to pay dividends from retained earnings or net income. As of March 31, 2024, ALLETE was in compliance with its financial covenants.

ALLETE, Inc. First Quarter 2024 Form 10-Q

19

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES

Power Purchase and Sale Agreements. Our long-term PPAs have been evaluated under the accounting guidance for variable interest entities. We have determined that either we have no variable interest in the PPAs or, where we do have variable interests, we are not the primary beneficiary; therefore, consolidation is not required. These conclusions are based on the fact that we do not have both control over activities that are most significant to the entity and an obligation to absorb losses or receive benefits from the entity’s performance. Our financial exposure relating to these PPAs is limited to our capacity and energy payments.

Our PPAs are summarized in Note 9. Commitments, Guarantees and Contingencies to the Consolidated Financial Statements in our 2023 Form 10-K, with additional disclosure provided in the following paragraphs.

Square Butte PPA. As of March 31, 2024, Square Butte had total debt outstanding of $162.6 million. Fuel expenses are recoverable through Minnesota Power’s fuel adjustment clause and include the cost of coal purchased from BNI Energy under a long-term contract. Minnesota Power’s cost of power purchased from Square Butte during the three months ended March 31, 2024, was $22.9 million ($22.1 million for the same period in 2023). This reflects Minnesota Power’s pro rata share of total Square Butte costs based on the 50 percent output entitlement. Included in this amount was Minnesota Power’s pro rata share of interest expense of $1.3 million ($1.3 million for the same period in 2023). Minnesota Power’s payments to Square Butte are approved as a purchased power expense for ratemaking purposes by both the MPUC and the FERC.

Minnkota Power PSA. Minnesota Power has a PSA with Minnkota Power, which commenced in 2014. Under the PSA, Minnesota Power is selling a portion of its entitlement from Square Butte to Minnkota Power, resulting in Minnkota Power’s net entitlement increasing and Minnesota Power’s net entitlement decreasing until Minnesota Power’s share is eliminated at the end of 2025. Of Minnesota Power’s 50 percent output entitlement, Minnesota Power sold to Minnkota Power approximately 41 percent in 2024 and 37 percent in 2023.

Coal, Rail and Shipping Contracts. Minnesota Power has coal supply agreements providing for the purchase of a significant portion of its coal requirements through December 2025. Minnesota Power also has coal transportation agreements in place for the delivery of a significant portion of its coal requirements through December 2024. The costs of fuel and related transportation costs for Minnesota Power’s generation are recoverable from Minnesota Power’s utility customers through the fuel adjustment clause.

Environmental Matters.

Our businesses are subject to regulation of environmental matters by various federal, state, and local authorities. A number of regulatory changes to the Clean Air Act, the Clean Water Act and various waste management requirements have been promulgated by both the EPA and state authorities over the past several years. Minnesota Power’s facilities are subject to additional requirements under many of these regulations. Minnesota Power is reshaping its generation portfolio, over time, to reduce its reliance on coal, has installed cost-effective emission control technology, and advocates for sound science and policy during rulemaking implementation.

We consider our businesses to be in substantial compliance with currently applicable environmental regulations and believe all necessary permits have been obtained. We anticipate that with many state and federal environmental regulations and requirements finalized, or to be finalized in the near future, potential expenditures for future environmental matters may be material and require significant capital investments. Minnesota Power has evaluated various environmental compliance scenarios using possible outcomes of environmental regulations to project power supply trends and impacts on customers.

We review environmental matters on a quarterly basis. Accruals for environmental matters are recorded when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated based on current law and existing technologies. Accruals are adjusted as assessment and remediation efforts progress, or as additional technical or legal information becomes available. Accruals for environmental liabilities are included in the Consolidated Balance Sheet at undiscounted amounts and exclude claims for recoveries from insurance or other third parties. Costs related to environmental contamination treatment and cleanup are expensed unless recoverable in rates from customers.

Air. The electric utility industry is regulated both at the federal and state level to address air emissions. Minnesota Power’s thermal generating facilities mainly burn low-sulfur western sub-bituminous coal. All of Minnesota Power’s coal-fired generating facilities are equipped with pollution control equipment such as scrubbers, baghouses and low NOX technologies. Under currently applicable environmental regulations, these facilities are substantially compliant with emission requirements.

ALLETE, Inc. First Quarter 2024 Form 10-Q

20

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES (Continued)

Environmental Matters (Continued)

Cross-State Air Pollution Rule (CSAPR). The CSAPR requires certain states in the eastern half of the U.S., including Minnesota, to reduce power plant emissions that contribute to ozone or fine particulate pollution in other states. The CSAPR does not require installation of controls but does require facilities have sufficient allowances to cover their emissions on an annual basis. These allowances are allocated to facilities from each state’s annual budget and can be bought and sold. Based on our review of the NOX and SO2 allowances issued and pending issuance as well as consideration of current rules, we currently expect generation levels and emission rates will result in continued compliance with the CSAPR. Minnesota Power will continue to monitor ongoing CSAPR rulemakings and compliance implementation, including the EPA’s Good Neighbor Rule which modifies certain aspects of the CSAPR’s program scope and extent (see EPA Good Neighbor Plan for 2015 Ozone NAAQS).

National Ambient Air Quality Standards (NAAQS). The EPA is required to review the NAAQS every five years. If the EPA determines that a state’s air quality is not in compliance with the NAAQS, the state is required to adopt plans describing how it will reduce emissions to attain the NAAQS. Minnesota Power actively monitors NAAQS developments, and the EPA is currently reviewing the primary or secondary NAAQS for NOx, SO2, and ozone. On February 7, 2024, the EPA announced a final rule lowering the annual primary standard for fine particulate matter while retaining other existing primary and secondary standards such as those for coarse particulate matter. The Company is reviewing the new standard to determine potential impacts. Anticipated timelines and compliance costs related to this new standard and other potential NAAQS revisions cannot yet be estimated; however, costs could be material. Minnesota Power would seek recovery of additional costs through a rate proceeding.

EPA Good Neighbor Plan for 2015 Ozone NAAQS. On June 5, 2023, after disapproving state implementation plans, the EPA published a final Federal Implementation Plan (FIP) rule in the Federal Register, the Good Neighbor Plan, to address regional ozone transport for the 2015 Ozone NAAQS by reducing NOx emissions during the period of May 1 through September 30 (ozone season). In its justification for the final rule, the EPA asserted that 23 states, including Minnesota, were modeled as significant contributors to downwind states’ challenges in attaining or maintaining ozone NAAQS compliance within their state borders. The Good Neighbor Plan is designed to resolve this interstate transport issue by implementing a variety of NOx reduction strategies, including federal implementation plan requirements, NOx emission limitations, and ozone season allowance program requirements. The final rule imposed restrictions on fossil-fuel fired power plants in 22 states and on certain industrial sources in 20 states, with implementation occurring through changes to the existing CSAPR program for power plants.

Since the EPA partially disapproved the Good Neighbor State Implementation Plans (SIPs) for the states of Minnesota and Wisconsin, among others, Minnesota is subject to the final Good Neighbor Plan. However, Minnesota Power and a coalition of other Minnesota utilities and industry (the parties) co-filed challenges to the EPA’s final Minnesota SIP disapproval, submitting a petition for reconsideration and stay to the EPA, and a petition for judicial review to the U.S. Court of Appeals for the Eighth Circuit (Eighth Circuit Court). The parties are challenging and requesting reconsideration of certain technical components of the EPA’s review and subsequent partial disapproval of the state of Minnesota’s SIP. On July 5, 2023, the Eighth Circuit Court granted a stay of the SIP disapproval preventing the Good Neighbor Plan from taking effect in Minnesota. On March 28, 2024, the EPA issued a partial denial of several administrative reconsideration and stay petitions, including from the Minnesota coalition.

On September 29, 2023, the EPA issued an updated final interim rule addressing the stays in Minnesota and five other states, formally delaying the effective date of the final FIP for states with active stays in place. The state of Minnesota was therefore not subject to compliance obligations for the 2023 ozone season. Future compliance obligations will depend on resolution of the stay. Additionally, challenges have been filed against the final FIP rule by the Minnesota coalition parties and other entities, although the Minnesota coalition FIP challenge is currently in abeyance pending resolution of the SIP disapproval case. On February 21, 2024, the U.S. Supreme Court heard arguments from several states and industry groups requesting a national stay of the FIP rule. Anticipated compliance costs related to final Good Neighbor Plan compliance cannot yet be estimated due to uncertainties about SIP approval resolution, implementation timing, FIP rule outcome, and allowance costs and facility emissions during the ozone season. However, the costs could be material, including costs of additional NOx controls, emission allowance program participation, or operational changes, if any are required. Minnesota Power would seek recovery of additional costs through a rate proceeding.

ALLETE, Inc. First Quarter 2024 Form 10-Q

21

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES (Continued)

Environmental Matters (Continued)

EPA National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial and Institutional Boilers and Process Heaters (Industrial Boiler MACT) Rule. A final rule issued by the EPA for Industrial Boiler MACT became effective in 2013 with compliance required at major existing sources in 2016, which applied to Minnesota Power’s Hibbard Renewable Energy Center and Rapids Energy Center. Compliance consisted largely of adjustments to fuels and operating practices and compliance costs were not material. After this initial rulemaking, litigation from 2016 through 2018 resulted in court orders directing that the EPA reconsider certain aspects of the regulation. A final rule incorporating these revisions became effective in December 2022, with a compliance deadline of October 6, 2025. Compliance costs are not expected to be material.

EPA Mercury and Air Toxics Standards (MATS) Rule. On April 25, 2024, the EPA published a final rule to revise the existing 2012 MATS Rule, which regulates air emissions of hazardous air pollutants from coal- and oil-fired electric generating units (EGUs). The final rule eliminates certain MATS compliance flexibility, lowers the particulate emission standard for all coal-fired EGUs, and reduces the mercury emission standard for lignite-fired EGUs. The rule will become effective 60 days after publication in the Federal Register, with compliance beginning in 2027. The MATS regulation applies at Minnesota Power’s Boswell facility, which is currently well-controlled for these emissions and already complying with some of the new requirements. The Company is analyzing the new rule but anticipates that its impacts to Boswell may be minimal. However, compliance costs cannot yet be estimated, and recovery of any additional costs would be sought through a rate proceeding.

Climate Change. The scientific community generally accepts that emissions of GHGs are linked to global climate change which creates physical and financial risks. Physical risks could include but are not limited to: increased or decreased precipitation and water levels in lakes and rivers; increased or other changes in temperatures; increased risk of wildfires; and changes in the intensity and frequency of extreme weather events. These all have the potential to affect the Company’s business and operations. We are addressing climate change by taking the following steps that also ensure reliable and environmentally compliant generation resources to meet our customers’ requirements:

•Expanding renewable power supply for both our operations and the operations of others;

•Providing energy conservation initiatives for our customers and engaging in other demand side management efforts;

•Improving efficiency of our generating facilities;

•Supporting research of technologies to reduce carbon emissions from generating facilities and carbon sequestration efforts;

•Evaluating and developing less carbon intensive future generating assets such as efficient and flexible natural gas‑fired generating facilities;

•Managing vegetation on right-of-way corridors to reduce potential wildfire or storm damage risks; and

•Practicing sound forestry management in our service territories to create landscapes more resilient to disruption from climate-related changes, including planting and managing long-lived conifer species.

EPA Regulation of GHG Emissions. On April 25, 2024, the EPA issued several final greenhouse gas regulations to establish emissions standards and guidelines for fossil fuel-fired electric generating units (EGUs) under Section 111 of the Clean Air Act (CAA). The final rules revise new source performance standards (NSPS) for new, modified and reconstructed EGUs (Section 111(b) of the CAA) and creates new emission guidelines for existing EGUs (Section 111(d) of the CAA). The action also officially repeals the predecessor regulation “Affordable Clean Energy Rule”, first issued in 2019 and later vacated in 2021. Compliance will be required beginning January 1, 2030 for existing sources, and upon commencing operation of new units. The 111(d) rule also requires states to submit plans to provide for the establishment, implementation and enforcement of standards of performance for existing sources. States must submit their plans to the EPA within 24 months after publication of the final emissions guidelines.

The final 111 rules apply to several Company assets, including existing EGUs at the Boswell and Laskin facilities as well as the proposed combined cycle natural gas-fired generating facility, NTEC. The Company is reviewing the new rule, but anticipates compliance may require operational or planning adjustments. The state implementation plan process for Section 111(d) existing units will also be a factor in determining specific requirements and timing. We are unable to predict compliance costs at this time; however, the costs could be material. Minnesota Power would seek recovery of additional costs through a rate proceeding.

Water. The Clean Water Act requires NPDES permits be obtained from the EPA or delegated state agencies for any wastewater discharged into navigable waters. We have obtained all necessary NPDES permits, including NPDES storm water permits for applicable facilities, to conduct our operations.

ALLETE, Inc. First Quarter 2024 Form 10-Q

22

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES (Continued)

Environmental Matters (Continued)

Steam Electric Power Generating Effluent Limitations Guidelines. In 2015, the EPA issued revised federal effluent limitation guidelines (ELG) for steam electric power generating stations under the Clean Water Act. It set effluent limits and prescribed Best Available Control Technology (BACT) for several wastewater streams, including flue gas desulphurization (FGD) water, bottom ash transport water and coal combustion landfill leachate. In October 2020, the EPA published a final ELG Rule allowing re-use of bottom ash transport water in FGD scrubber systems with limited discharges related to maintaining system water balance. The rule set technology standards and numerical pollutant limits for discharges of bottom ash transport water and FGD wastewater. Compliance deadlines depend on subcategory, with compliance generally required as soon as possible, beginning after October 13, 2021, but no later than December 31, 2025, or December 31, 2028, in some specific cases.

On April 25, 2024, the EPA released a pre-publication version of a final ELG rule to update the 2020 ELGs. In the final rule, the EPA is revising ELGs for existing sources, including establishing zero discharge limitations for bottom ash transport water, FGD wastewater, and combustion residual leachate, and allowing states to set discharge limits for legacy wastewater in surface impoundments based on best professional judgment. The rule proposes to maintain exemptions for units permanently ceasing coal combustion by 2028, and adds a new subcategory for units that have already complied with either the 2015 or 2020 ELG rules and which will retire by 2032. The final ELG rule also establishes mercury and arsenic limitations for functionally equivalent discharges of leachate via groundwater to surface water. Compliance deadlines are determined by the applicable state permitting authority. Compliance deadlines could be required as soon as 60 days after the final rule is published in the Federal Register, but no later than December 31, 2029.

Bottom ash transport and FGD wastewater ELGs are not expected to have a significant impact on Minnesota Power operations. Zero leachate discharge requirements have the potential to impact dewatering associated with the closed Taconite Harbor dry ash landfill and Laskin’s closed Cell E impoundment. New limitations for arsenic and mercury related to functionally equivalent (groundwater to surface water) discharges are not currently anticipated to impact Minnesota Power facilities.

We estimate no additional material compliance costs for ELG bottom ash water and FGD requirements. Compliance costs we might incur related to other ELG waste streams (e.g., leachate) or other potential future water discharge regulations at Minnesota Power facilities cannot be estimated; however, the costs could be material, including costs associated with wastewater treatment and re-use. Minnesota Power would seek recovery of additional costs through a rate proceeding.

Permitted Water Discharges – Sulfate. In 2017, the MPCA released a draft water quality standard in an attempt to update Minnesota’s existing 10 mg/L sulfate limit for waters used for the production of wild rice with the proposed rulemaking heard before an administrative law judge (ALJ). In 2018, the ALJ rejected significant portions of the proposed rulemaking and the MPCA subsequently withdrew the rulemaking. The existing 10 mg/L limit remains in place, but the MPCA is currently prohibited under state law from listing wild rice waters as impaired or requiring sulfate reduction technology.

The federal Clean Water Act requires the MPCA to update the state's impaired water list every two years. Beginning in 2021 through the latest draft approved by the EPA in April 2024, this list now includes Minnesota lakes and streams identified as wild rice waters that are listed for sulfate impairment. The list could subsequently be used to set sulfate limits in discharge permits for power generation facilities and municipal and industrial customers, including paper and pulp facilities, and mining operations. At this time, we are unable to determine the specific impacts these developments may have on Minnesota Power operations or its customers, if any. Minnesota Power would seek recovery of additional costs through a rate proceeding.

Solid and Hazardous Waste. The Resource Conservation and Recovery Act of 1976 regulates the management and disposal of solid and hazardous wastes. We are required to notify the EPA of hazardous waste activity and, consequently, routinely submit reports to the EPA.

Coal Ash Management Facilities. Minnesota Power produces the majority of its coal ash at Boswell, with small amounts of ash generated at Hibbard Renewable Energy Center. Ash storage and disposal methods include storing ash in clay-lined onsite impoundments (ash ponds), disposing of dry ash in a lined dry ash landfill, applying ash to land as an approved beneficial use, and trucking ash to state permitted landfills.

ALLETE, Inc. First Quarter 2024 Form 10-Q

23

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES (Continued)

Environmental Matters (Continued)

Coal Combustion Residuals from Electric Utilities (CCR). In 2015, the EPA published a final rule (2015 Rule) regulating CCR as nonhazardous waste under Subtitle D of the Resource Conservation and Recovery Act (RCRA) in the Federal Register. The rule included additional requirements for new landfill and impoundment construction as well as closure activities related to certain existing impoundments. Costs of compliance for Boswell and Laskin are expected to be incurred primarily over the next 12 years and be between approximately $65 million and $120 million. Compliance costs for CCR at Taconite Harbor are not expected to be material. Minnesota Power would seek recovery of additional costs through a rate proceeding.

Minnesota Power continues to work on minimizing compliance costs through evaluation of beneficial re-use and recycling of CCR. In 2018, a U.S. District Court for the District of Columbia decision vacated specific provisions of the CCR rule, which resulted in a change to the status of several existing clay-lined impoundments at Boswell being considered unlined. In September 2020, the EPA finalized the CCR Part A Rule, which required all unlined impoundments to cease disposal and initiate closure. Upon completion of dry ash conversion activities, Boswell ceased disposal in both impoundments in September 2022. Both impoundments are now inactive and have initiated closure.

On April 25, 2024, the EPA finalized the CCR Legacy Impoundment Rule. The final rule expands the scope of units regulated under the CCR rule to include legacy ponds (inactive surface impoundments at inactive facilities) and creates a new category of units called CCR management units, which includes inactive and closed impoundments and landfills as well as other non-containerized accumulations of CCR. The rule requires all regulated generating facilities to evaluate and identify past deposits of CCR materials on their sites and close or re-close existing CCR units to meet current closure standards, as well as install groundwater monitoring systems, conduct groundwater monitoring, and implement groundwater corrective actions as necessary. Additionally, the EPA finalized portions of the proposed CCR Part B Rule, which allows CCR Units to certify closure while conducting groundwater remediation activities. This rule is currently under review; however impacts to previously closed CCR Units at Boswell and Laskin are anticipated. Compliance costs for Minnesota Power facilities cannot be estimated at this time; however, the costs could be material. Minnesota Power would seek recovery of additional costs through a rate proceeding.

Additionally, the EPA released a proposed CCR Part B rulemaking in February 2020 addressing options for beneficial reuse of CCR materials, alternative liner demonstrations and other CCR regulatory revisions. Portions of the Part B rule addressing alternative liner equivalency standards were finalized in November 2020. Finalization of the remaining beneficial reuse requirements are expected in late 2024. The final CCR federal permit rule is expected in the first half of 2026. The final federal permit rule will finalize procedures for implementing a CCR federal permit program.

Other Environmental Matters.

Manufactured Gas Plant Site. We are reviewing and addressing environmental conditions at a former manufactured gas plant site located in Superior, Wisconsin, and formerly operated by SWL&P. SWL&P has been working with the Wisconsin Department of Natural Resources (WDNR) in determining the extent and location of contamination at the site and surrounding properties. As of March 31, 2024, SWL&P has recorded a liability of approximately $1 million for remediation costs at this site. SWL&P has recorded the recovery of the remediation costs associated with the site as a regulatory asset as we expect recovery of these costs to be allowed by the PSCW.

Other Matters.

Letters of Credit, Surety Bonds and Other Indemnifications.

We have multiple credit facility agreements in place that provide the ability to issue standby letters of credit to satisfy contractual security requirements across our businesses. As of March 31, 2024, we had $150.1 million of outstanding letters of credit issued, including those issued under our revolving credit facility. We do not believe it is likely that any of these outstanding letters of credit will be drawn upon.

In April 2024, under the tax credit transferability provision of the Inflation Reduction Act, we entered into an agreement with a third party to sell a portion of our production tax credits. ALLETE has indemnified the third party for the value of production tax credits sold to date of approximately $14 million.

Regulated Operations. As of March 31, 2024, we had $25.4 million outstanding in standby letters of credit at our Regulated Operations which are pledged as security to MISO, the NDPSC and state agencies.

ALLETE, Inc. First Quarter 2024 Form 10-Q

24

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES (Continued)

Other Matters (Continued)

ALLETE Clean Energy. ALLETE Clean Energy is party to PSAs that expire in various years between 2024 and 2039. As of March 31, 2024, ALLETE Clean Energy has $80.6 million outstanding in standby letters of credit, the majority of which are pledged as security under these PSAs.

Corporate and Other.

BNI Energy. As of March 31, 2024, BNI Energy had surety bonds outstanding of $82.4 million related to the reclamation liability for closing costs associated with its mine and mine facilities. Although its coal supply agreements obligate the customers to provide for the closing costs, additional assurance is required by federal and state regulations. BNI Energy’s total reclamation liability is currently estimated at $82.1 million. BNI Energy does not believe it is likely that any of these outstanding surety bonds will be drawn upon.

Investment in Nobles 2. The Nobles 2 wind energy facility requires standby letters of credit as security for certain contractual obligations. As of March 31, 2024, ALLETE South Wind has $10.1 million outstanding in standby letters of credit, related to its portion of the security requirements relative to its ownership in Nobles 2.

South Shore Energy. As of March 31, 2024, South Shore Energy had $29.7 million outstanding in standby letters of credit pledged as security in connection with the development of NTEC.

Legal Proceedings.

We are involved in litigation arising in the normal course of business. Also in the normal course of business, we are involved in tax, regulatory and other governmental audits, inspections, investigations and other proceedings that involve state and federal taxes, safety, and compliance with regulations, rate base and cost of service issues, among other things. We do not expect the outcome of these matters to have a material effect on our financial position, results of operations or cash flows.

NOTE 7. EARNINGS PER SHARE AND COMMON STOCK

We compute basic earnings per share using the weighted average number of shares of common stock outstanding during each period. The difference between basic and diluted earnings per share, if any, arises from non-vested restricted stock units and performance share awards granted under our Executive Long-Term Incentive Compensation Plan.

Three Months Ended March 31,		2024			2023
Reconciliation of Basic and Diluted		Dilutive			Dilutive
Earnings Per Share	Basic	Securities	Diluted	Basic	Securities	Diluted
Millions Except Per Share Amounts
Net Income Attributable to ALLETE	$50.7		$50.7	$58.2		$58.2
Average Common Shares	57.6	0.1	57.7	57.3	—	57.3
Earnings Per Share	$0.88		$0.88	$1.02		$1.02

ALLETE, Inc. First Quarter 2024 Form 10-Q

25

NOTE 8. INCOME TAX EXPENSE

	Three Months Ended
	March 31,
	2024	2023
Millions
Current Income Tax Expense
Federal (a)	$3.5	$5.6
State	3.4	2.2
Total Current Income Tax Expense	$6.9	$7.8
Deferred Income Tax Expense (Benefit)
Federal (b)	$(5.0)	$(8.3)
State	2.4	2.1
Investment Tax Credit Amortization	(0.3)	(0.1)
Total Deferred Income Tax Benefit	$(2.9)	$(6.3)
Total Income Tax Expense	$4.0	$1.5

(a)For the three months ended March 31, 2024 and 2023, the federal current tax expense was partially offset by production tax credits.

(b)For the three months ended March 31, 2024 and 2023, the federal income tax benefit is primarily due to production tax credits.

The Company's tax provision for interim periods is determined using an estimate of its annual effective tax rate, adjusted for discrete items arising in that quarter. In each quarter, the Company updates its estimate of the annual effective tax rate and if the estimated annual effective tax rate changes, the Company would make a cumulative adjustment in that quarter.

	Three Months Ended
Reconciliation of Taxes from Federal Statutory	March 31,
Rate to Total Income Tax Expense	2024		2023
Millions
Income Before Income Taxes	$41.0		$39.1
Statutory Federal Income Tax Rate	21	%	21	%
Income Taxes Computed at Statutory Federal Rate	$8.6		$8.2
Increase (Decrease) in Income Tax Due to:
State Income Taxes – Net of Federal Income Tax Benefit	4.6		3.4
Production Tax Credits (a)	(11.6)		(10.4)
Investment Tax Credits (a)	(0.3)		(2.2)
Regulatory Differences – Excess Deferred Tax	(3.5)		(2.8)
Non-Controlling Interest in Subsidiaries	2.8		3.8
AFUDC – Equity	(0.6)		(0.3)
Other	4.0		1.8
Total Income Tax Expense	$4.0		$1.5

(a)For the three months ended March 31, 2024 and 2023, the credits are presented net of any estimated discount on the sale of certain credits.

For the three months ended March 31, 2024, the effective tax rate was 9.7 percent (3.8 percent for the three months ended March 31, 2023). The effective tax rates for 2024 and 2023 were primarily impacted by production tax credits.

Uncertain Tax Positions. As of March 31, 2024, we had gross unrecognized tax benefits of $1.1 million ($1.1 million as of December 31, 2023). Of the total gross unrecognized tax benefits, $0.6 million represents the amount of unrecognized tax benefits included on the Consolidated Balance Sheet that, if recognized, would favorably impact the effective income tax rate. The unrecognized tax benefit amounts have been presented as an increase to the net deferred tax liability on the Consolidated Balance Sheet.

ALLETE and its subsidiaries file a consolidated federal income tax return as well as combined and separate state income tax returns in various jurisdictions. ALLETE is currently under examination by the state of Minnesota for the tax years 2020 through 2022. ALLETE has no open federal audits and is no longer subject to federal examination for years before 2021 or state examination for years before 2020. Additionally, the statute of limitations related to the federal tax credit carryforwards will remain open until those credits are utilized in subsequent returns.

ALLETE, Inc. First Quarter 2024 Form 10-Q

26

NOTE 9. PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS

Components of Net Periodic Benefit Cost (Credit)	Pension		Other Postretirement
Three Months Ended March 31,	2024	2023	2024	2023
Millions
Service Cost	$1.6	$1.6	$0.4	$0.6
Non-Service Cost Components (a)
Interest Cost	9.7	10.1	1.0	1.5
Expected Return on Plan Assets	(11.2)	(10.9)	(2.8)	(2.8)
Amortization of Prior Service Credits	—	—	(2.9)	(1.8)
Amortization of Net Loss	1.6	1.4	(0.8)	(0.5)
Net Periodic Benefit Cost (Credit)	$1.7	$2.2	$(5.1)	$(3.0)

(a)These components of net periodic benefit cost (credit) are included in the line item “Other” under Other Income (Expense) on the Consolidated Statement of Income.

Employer Contributions. For the three months ended March 31, 2024, we contributed $25.0 million in cash to the defined benefit pension plans ($6.5 million for the three months ended March 31, 2023); we do not expect to make additional contributions to our defined benefit pension plans in 2024. For the three months ended March 31, 2024 and 2023, we made no contributions to our other postretirement benefit plans; we do not expect to make any contributions to our other postretirement benefit plans in 2024.

NOTE 10. BUSINESS SEGMENTS

We present two reportable segments: Regulated Operations and ALLETE Clean Energy. We measure performance of our operations through budgeting and monitoring of contributions to consolidated net income by each business segment.

Regulated Operations includes three operating segments which consist of our regulated utilities, Minnesota Power and SWL&P, as well as our investment in ATC. ALLETE Clean Energy is our business focused on developing, acquiring and operating clean and renewable energy projects. We also present Corporate and Other which includes New Energy, a renewable energy development company, BNI Energy, our coal mining operations in North Dakota, ALLETE Properties, our legacy Florida real estate investment, along with our investment in Nobles 2, South Shore Energy, our non-rate regulated, Wisconsin subsidiary developing NTEC, other business development and corporate expenditures, unallocated interest expense, a small amount of non-rate base generation, land holdings in Minnesota, and earnings on cash and investments.

ALLETE, Inc. First Quarter 2024 Form 10-Q

27

NOTE 10. BUSINESS SEGMENTS (Continued)

	Three Months Ended
	March 31,
	2024	2023
Millions
Operating Revenue
Regulated Operations
Residential	$51.5	$49.4
Commercial	49.7	47.7
Municipal	9.0	8.9
Industrial	159.5	144.9
Other Power Suppliers	40.0	35.9
Other	28.6	25.8
Total Regulated Operations	338.3	312.6
ALLETE Clean Energy
Long-term PSA	17.8	18.4
Sale of Wind Energy Facilities	—	181.8
Other	1.3	1.3
Total ALLETE Clean Energy	19.1	201.5
Corporate and Other
Long-term Contract	25.4	25.5
Sale of Renewable Development Projects	13.9	19.8
Other	6.6	5.5
Total Corporate and Other	45.9	50.8
Total Operating Revenue	$403.3	$564.9
Net Income Attributable to ALLETE
Regulated Operations	$44.2	$40.6
ALLETE Clean Energy	3.8	8.5
Corporate and Other	2.7	9.1
Total Net Income Attributable to ALLETE	$50.7	$58.2

	March 31, 2024	December 31, 2023
Millions
Assets
Regulated Operations	$4,345.1	$4,335.0
ALLETE Clean Energy	1,580.0	1,594.1
Corporate and Other	679.5	727.3
Total Assets	$6,604.6	$6,656.4

ALLETE, Inc. First Quarter 2024 Form 10-Q

28

NOTE 11. SUBSEQUENT EVENT – AGREEMENT AND PLAN OF MERGER

On May 5, 2024, ALLETE entered into the Merger Agreement. Pursuant to the Merger Agreement, on the terms and subject to the conditions set forth therein, Alloy Merger Sub will merge with and into ALLETE, with ALLETE continuing as the surviving corporation in the Merger and becoming a subsidiary of Alloy Parent.

Subject to the terms and conditions set forth in the Merger Agreement, which has been unanimously approved by the board of directors of ALLETE, at the effective time of the Merger (Effective Time), each share of common stock, without par value, of ALLETE (ALLETE common stock) issued and outstanding immediately prior to the Effective Time (other than shares of ALLETE common stock held by any holder who properly exercises dissenters’ rights under Minnesota law in respect of such shares and any shares of ALLETE common stock held by an affiliate of Alloy Parent) shall be converted into the right to receive $67.00 in cash, without interest (Merger Consideration). The aggregate equity value of the ALLETE common stock acquired by Parent will be approximately $3.9 billion as calculated as of May 5, 2024.

In addition, at the Effective Time, each restricted stock unit with respect to ALLETE common stock subject to time-based vesting that is outstanding immediately prior to the Effective Time (RSU) will be cancelled and converted into a contingent right to receive an amount in cash, without interest, equal to the Merger Consideration, payable (i) in the case of such right converted from unvested RSUs, upon the same vesting conditions as applied to the corresponding RSU or (ii) in the case of such right converted from vested RSUs, as soon as reasonably practicable following the closing date of the Merger (the Closing Date). Each performance share award with respect to ALLETE common stock that is outstanding and unvested immediately prior to the Effective Time will be cancelled and converted into a right to receive, without interest, the Merger Consideration multiplied by the number of shares of ALLETE common stock subject to the award, determined based on attainment of the greater of target and actual performance as of the last business day immediately preceding the Closing Date. A pro rata portion (based on the elapsed portion of the performance period at that time) of the converted performance share awards will be paid out as soon as reasonably practicable following the Closing Date, with the remainder of the award being subject to time-vesting for the remainder of the applicable performance period. Further, purchase rights accumulated during the offering period in effect under the Company’s Employee Stock Purchase Plan (ESPP) immediately prior to closing will be automatically exercised into shares of ALLETE common stock no later than five business days prior to the Closing Date, and the ESPP will be terminated as of immediately prior to the Closing Date.

Consummation of the Merger is subject to various closing conditions, including: (1) approval of the shareholders of the Company; (2) receipt of all required regulatory approvals without the imposition of a Burdensome Condition (as defined in the Merger Agreement); (3) absence of any law or order prohibiting the consummation of the Merger; (4) subject to materiality qualifiers, the accuracy of each party’s representations and warranties; (5) each party’s compliance in all material respects with its obligations and covenants under the Merger Agreement; and (6) the absence of a material adverse effect with respect to the Company. The Merger Agreement contains certain termination rights for ALLETE and Alloy Parent, which were described in a Current Report of Form 8-K filed by ALLETE on May 6, 2024. In the Merger Agreement, among other things, ALLETE has agreed, subject to certain exceptions, to, and to cause each of its subsidiaries to conduct its business in the ordinary course, consistent with past practice, from the date of the Merger Agreement until the Effective Time, and not to take certain actions prior to the closing of the Merger without the prior written consent of Alloy Parent (which consent shall not be unreasonably withheld, conditioned or delayed, except where ALLETE seeks Alloy Parent’s consent to enter into a material new line of business or cease operations of an existing material line of business). The Merger Agreement also provides that the Company may request that Alloy Parent purchase up to a total of $300 million of preferred stock of the Company in the second half of 2025, subject to certain parameters. If Alloy Parent declines to purchase the preferred stock, the Company will have the right to issue Company common stock up to certain limits.

ALLETE, Inc. First Quarter 2024 Form 10-Q

29

ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL

CONDITION AND RESULTS OF OPERATIONS

OVERVIEW

The following discussion should be read in conjunction with our Consolidated Financial Statements and notes to those statements, Management’s Discussion and Analysis of Financial Condition and Results of Operations from our 2023 Form 10-K and the other financial information appearing elsewhere in this report. In addition to historical information, the following discussion and other parts of this Form 10-Q contain forward-looking information that involves risks and uncertainties. Readers are cautioned that forward-looking statements should be read in conjunction with our disclosures in this Form 10-Q and our 2023 Form 10-K under the headings: “Forward-Looking Statements” located on page 7 and “Risk Factors” located in Part I, Item 1A, beginning on page 25 of our 2023 Form 10-K. The risks and uncertainties described in this Form 10-Q and our 2023 Form 10-K are not the only risks facing our Company. Additional risks and uncertainties that we are not presently aware of, or that we currently consider immaterial, may also affect our business operations. Our business, financial condition or results of operations could suffer if the risks are realized.

On May 5, 2024, ALLETE entered into the Merger Agreement. (See Note 11. Subsequent Event – Agreement and Plan of Merger.)

Regulated Operations includes our regulated utilities, Minnesota Power and SWL&P, as well as our investment in ATC, a Wisconsin-based regulated utility that owns and maintains electric transmission assets in portions of Wisconsin, Michigan, Minnesota and Illinois. Minnesota Power provides regulated utility electric service in northeastern Minnesota to approximately 150,000 retail customers. Minnesota Power also has 14 non-affiliated municipal customers in Minnesota. SWL&P is a Wisconsin utility and a wholesale customer of Minnesota Power. SWL&P provides regulated utility electric, natural gas and water service in northwestern Wisconsin to approximately 15,000 electric customers, 13,000 natural gas customers and 10,000 water customers. Our regulated utility operations include retail and wholesale activities under the jurisdiction of state and federal regulatory authorities. (See Note 2. Regulatory Matters.)

ALLETE Clean Energy focuses on developing, acquiring, and operating clean and renewable energy projects. ALLETE Clean Energy currently owns and operates, in seven states, more than 1,200 MW of nameplate capacity wind energy generation with a majority contracted under PSAs of various durations. In addition, ALLETE Clean Energy also engages in the development of wind energy facilities to operate under long-term PSAs or for sale to others upon completion.

Corporate and Other is comprised of New Energy, a renewable development company; our investment in Nobles 2, an entity that owns and operates a 250 MW wind energy facility in southwestern Minnesota; South Shore Energy, our non-rate regulated, Wisconsin subsidiary developing NTEC, an approximately 600 MW proposed combined-cycle natural gas-fired generating facility; BNI Energy, our coal mining operations in North Dakota; ALLETE Properties, our legacy Florida real estate investment; other business development and corporate expenditures; unallocated interest expense; a small amount of non-rate base generation; land holdings in Minnesota; and earnings on cash and investments.

ALLETE is incorporated under the laws of Minnesota. Our corporate headquarters are in Duluth, Minnesota. Statistical information is presented as of March 31, 2024, unless otherwise indicated. All subsidiaries are wholly-owned unless otherwise specifically indicated. References in this report to “we,” “us” and “our” are to ALLETE and its subsidiaries, collectively.

Financial Overview

The following net income discussion summarizes a comparison of the three months ended March 31, 2024, to the three months ended March 31, 2023.

Net income attributable to ALLETE for the three months ended March 31, 2024, was $50.7 million, or $0.88 per diluted share, compared to $58.2 million, or $1.02 per diluted share, for the same period in 2023. Net income in 2024 includes interim rate refund reserves of $3.9 million after-tax, or $0.07 per share, due to Minnesota Power’s rate case settlement. (See Note 2. Regulatory Matters.) Net income in 2024 also includes transaction costs of $1.2 million after-tax, or $0.02 per share, related to the Merger. (See Note 11. Subsequent Event – Agreement and Plan of Merger.)

ALLETE, Inc. First Quarter 2024 Form 10-Q

30

ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL

CONDITION AND RESULTS OF OPERATIONS (Continued)

Regulated Operations net income attributable to ALLETE was $44.2 million for the three months ended March 31, 2024, compared to $40.6 million for the same period in 2023. Net income at Minnesota Power was higher than 2023 primarily due to the implementation of interim rates on January 1, 2024, net of reserves related to Minnesota Power’s rate case settlement. (See Note 2. Regulatory Matters.) This increase was partially offset by higher operating and maintenance and depreciation expenses. Net income at SWL&P and our after-tax equity earnings in ATC were similar to 2023. (See Note 3. Equity Investments.)

ALLETE Clean Energy net income attributable to ALLETE was $3.8 million for the three months ended March 31, 2024, compared to $8.5 million for the same period in 2023. Net income in 2024 reflected a forced outage located near its Caddo wind energy facility and a transformer outage at its Diamond Spring wind energy facility resulting in lower earnings. These decreases were partially offset by lower operating and maintenance expense.

Corporate and Other net income attributable to ALLETE was $2.7 million for the three months ended March 31, 2024, compared to $9.1 million for the same period in 2023. Net income in 2024 reflects lower earnings from Minnesota solar projects as investment tax credits were recognized in 2023 for the projects. Net income in 2024 also reflects higher income taxes and interest expense compared to 2023. Net income in 2024 also includes transaction costs of $1.2 million after-tax related to the Merger. (See Note 11. Subsequent Event – Agreement and Plan of Merger.) Net income at New Energy was $4.0 million in 2024 compared to $4.1 million in 2023.

COMPARISON OF THE THREE MONTHS ENDED MARCH 31, 2024 AND 2023

(See Note 10. Business Segments for financial results by segment.)

Regulated Operations

Three Months Ended March 31,	2024	2023
Millions
Operating Revenue – Utility	$338.3	$312.6
Fuel, Purchased Power and Gas – Utility	133.7	118.6
Transmission Services – Utility	22.7	20.1
Operating and Maintenance	66.8	61.9
Depreciation and Amortization	46.4	44.5
Taxes Other than Income Taxes	15.7	15.9
Operating Income	53.0	51.6
Interest Expense	(16.0)	(15.5)
Equity Earnings	5.7	6.0
Other Income	6.4	2.5
Income Before Income Taxes	49.1	44.6
Income Tax Expense	4.9	4.0
Net Income Attributable to ALLETE	$44.2	$40.6

ALLETE, Inc. First Quarter 2024 Form 10-Q

31

COMPARISON OF THE THREE MONTHS ENDED MARCH 31, 2024 AND 2023 (Continued)

Regulated Operations (Continued)

Operating Revenue – Utility increased $25.7 million from 2023 primarily due to the implementation of interim rates on January 1, 2024, as well as higher fuel adjustment clause recoveries and kWh sales, partially offset by lower cost recovery rider revenue and gas sales.

Interim retail rates for Minnesota Power, subject to refund, were approved by the MPUC and became effective January 1, 2024, resulting in revenue of $11.2 million, net of reserves related to Minnesota Power’s rate case settlement and rider revenue incorporated into base rates. (See Note 2. Regulatory Matters.)

Fuel adjustment clause revenue increased $8.4 million due to higher fuel and purchased power costs attributable to retail and municipal customers. (See Fuel, Purchased Power and Gas – Utility.)

Higher kWh sales increased revenue by $7.8 million from 2023 reflecting higher sales to industrial customers and other power suppliers as well as higher market prices, partially offset by lower sales to residential, commercial and municipal customers. Sales to industrial customers increased primarily due to higher sales to taconite customers reflecting Cliff’s Northshore mine operating in 2024 compared to being idled in the first quarter of 2023. Sales to other power suppliers, which are sold at market-based prices into the MISO market on a daily basis or through PSAs of various durations, increased reflecting more market sales and higher market prices in 2024 compared to 2023. Sales to residential, commercial and municipal customers decreased from 2023 primarily due to warmer weather in 2024 compared to 2023.

Kilowatt-hours Sold			Variance
Three Months Ended March 31,	2024	2023	Quantity	%
Millions
Regulated Utility
Retail and Municipal
Residential	306	321	(15)	(4.7)	%
Commercial	338	347	(9)	(2.6)	%
Industrial	1,798	1,658	140	8.4	%
Municipal	125	128	(3)	(2.3)	%
Total Retail and Municipal	2,567	2,454	113	4.6	%
Other Power Suppliers	757	696	61	8.8	%
Total Regulated Utility Kilowatt-hours Sold	3,324	3,150	174	5.5	%

Revenue from electric sales to taconite customers accounted for 32 percent of regulated operating revenue in 2024 (30 percent in 2023). Revenue from electric sales to paper, pulp and secondary wood product customers accounted for 5 percent of regulated operating revenue in 2024 (4 percent in 2023). Revenue from electric sales to pipelines and other industrial customers accounted for 10 percent of regulated operating revenue in 2024 (11 percent in 2023).

Revenue from gas sales at SWL&P decreased $4.2 million reflecting fewer gas sales resulting from warmer weather and lower gas prices in 2024 compared to 2023. (See Fuel, Purchased Power and Gas – Utility.)

Operating Expenses increased $24.3 million, or 9 percent, from 2023.

Fuel, Purchased Power and Gas – Utility expense increased $15.1 million, or 13 percent, from 2023 primarily due to higher kWh sales, purchased power prices and fuel costs. These increases were partially offset by lower gas sales and prices.

Transmission Services – Utility expense increased $2.6 million, or 13 percent, from 2023 primarily due to higher MISO-related expense.

Operating and Maintenance expense increased $4.9 million, or 8 percent, from 2023 primarily due to higher salaries and wages, benefit costs, and contract and professional services.

Depreciation and Amortization expense increased $1.9 million, or 4 percent, from 2023 primarily due to a higher plant in service balance in 2024.

ALLETE, Inc. First Quarter 2024 Form 10-Q

32

COMPARISON OF THE THREE MONTHS ENDED MARCH 31, 2024 AND 2023 (Continued)

Regulated Operations (Continued)

Other Income increased $3.9 million from 2023 reflecting lower pension and other postretirement benefit plan non-service costs.

Income Tax Expense increased $0.9 million from 2023 primarily due to higher pre-tax income.

ALLETE Clean Energy

Three Months Ended March 31,	2024	2023
Millions
Operating Revenue
Contracts with Customers – Non-utility	$17.8	$200.2
Other – Non-utility (a)	1.3	1.3
Cost of Sales – Non-utility	—	181.6
Operating and Maintenance	13.5	14.3
Depreciation and Amortization	14.1	14.4
Taxes Other than Income Taxes	2.6	2.9
Operating Loss	(11.1)	(11.7)
Interest Expense	(0.1)	(0.3)
Other Income	1.6	0.2
Loss Before Income Taxes	(9.6)	(11.8)
Income Tax Benefit	(5.5)	(3.0)
Net Loss	(4.1)	(8.8)
Net Loss Attributable to Non-Controlling Interest	(7.9)	(17.3)
Net Income Attributable to ALLETE	$3.8	$8.5

(a)Represents non-cash amortization of differences between contract prices and estimated market prices on assumed PSAs.

Operating Revenue decreased $182.4 million from 2023. Operating revenue in 2023 reflected the sale of ALLETE Clean Energy’s Northern Wind project. In addition, operating revenue in 2024 was negatively impacted by a network outage located near ALLETE Clean Energy’s Caddo wind energy facility. The network outage began in the fourth quarter of 2023 resulting from a forced outage of a substation and the transmission lines feeding that substation. This forced outage increased congestion experienced by the Caddo wind energy facility resulting in lower kWh sales and pricing. (See Outlook - ALLETE Clean Energy.)

	Three Months Ended March 31,
	2024		2023
Production and Operating Revenue	kWh	Revenue	kWh	Revenue
Millions
Wind Energy Regions
East	73.4	$7.1	79.4	$7.4
Midwest	163.1	5.1	155.2	4.9
South	284.1	3.2	618.9	3.4
West	186.9	3.7	197.1	4.0
Sale of Wind Energy Facility	—	—	—	181.8
Total Production and Operating Revenue	707.5	$19.1	1,050.6	$201.5

Cost of Sales – Non-utility decreased $181.6 million from 2023. Cost of sales – Non-utility in 2023 reflected the sale of ALLETE Clean Energy’s Northern Wind project.

Other Income increased $1.4 million from 2023 primarily due to higher interest income in 2024 compared to 2023.

Income Tax Benefit increased $2.5 million from 2023 primarily due to lower net losses attributable to non-controlling interest.

ALLETE, Inc. First Quarter 2024 Form 10-Q

33

COMPARISON OF THE THREE MONTHS ENDED MARCH 31, 2024 AND 2023 (Continued)

ALLETE Clean Energy (Continued)

Net Loss Attributable to Non-Controlling Interest decreased $9.4 million from 2023 reflecting lower availability at ALLETE Clean Energy’s tax equity financed wind energy facilities resulting from the impacts of a network outage near the Caddo wind energy facility and a transformer outage at the Diamond Spring wind energy facility.

Corporate and Other

Operating Revenue decreased $4.9 million, or 10 percent, from 2023 primarily due to lower revenue from sales of renewable energy projects at New Energy in 2024 compared to 2023 reflecting the timing of project closings.

Net Income Attributable to ALLETE was $2.7 million in 2024 compared to $9.1 million in 2023. Net income in 2024 reflects lower earnings from Minnesota solar projects as investment tax credits were recognized in 2023 for the projects. Net income in 2024 also reflects higher income taxes and interest expense compared to 2023. Net income in 2024 also includes transaction costs of $1.2 million after-tax related to the Merger. (See Note 11. Subsequent Event – Agreement and Plan of Merger.) Net income at New Energy was $4.0 million in 2024 compared to $4.1 million in 2023.

Income Taxes – Consolidated

For the three months ended March 31, 2024, the effective tax rate was an expense of 9.7 percent (3.8 percent for the three months ended March 31, 2023) primarily due to higher pre-tax income.

We expect our annual effective tax rate in 2024 to be lower than 2023 primarily due to lower estimated pre-tax income. The estimated annual effective tax rate can differ from what a quarterly effective tax rate would otherwise be on a standalone basis, and this may cause quarter to quarter differences in the timing of income taxes. (See Note 8. Income Tax Expense.)

CRITICAL ACCOUNTING POLICIES

Certain accounting measurements under GAAP involve management’s judgment about subjective factors and estimates, the effects of which are inherently uncertain. Accounting measurements that we believe are most critical to our reported results of operations and financial condition include: regulatory accounting, pension and postretirement health and life actuarial assumptions, goodwill, impairment of long-lived assets, and taxation. These policies are reviewed with the Audit Committee of our Board of Directors on a regular basis and summarized in Part II, Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations of our 2023 Form 10-K.

OUTLOOK

For additional information see our 2023 Form 10-K.

On May 5, 2024, ALLETE entered into the Merger Agreement. (See Note 11. Subsequent Event – Agreement and Plan of Merger.) As a result of the Merger, transaction costs are expected to be material for the remainder of 2024.

ALLETE is an energy company committed to earning a financial return that rewards our shareholders, allows for reinvestment in our businesses, and sustains growth. The Company has a long-term objective of achieving consolidated earnings per share growth within a range of 5 percent to 7 percent.

ALLETE is predominately a regulated utility through Minnesota Power, SWL&P, and an investment in ATC. ALLETE’s strategy is to remain predominately a regulated utility while investing in ALLETE Clean Energy and New Energy and its Corporate and Other businesses to complement its regulated businesses, balance exposure to the utility’s industrial customers, and provide potential long-term earnings growth. ALLETE expects net income from Regulated Operations to be approximately 75 percent of total consolidated net income in 2024. ALLETE expects its businesses to generally provide regulated, contracted or recurring revenues, and to support sustained growth in net income and cash flow.

ALLETE, Inc. First Quarter 2024 Form 10-Q

34

OUTLOOK (Continued)

Minnesota Carbon-Free Legislation. On February 7, 2023, the Minnesota Governor signed into law legislation that updates the state’s renewable energy standard and requires Minnesota electric utilities to source retail sales with 100 percent carbon-free energy by 2040. The law increases the renewable energy standard from 25 percent renewable by 2025 to 55 percent renewable by 2035, and requires investor-owned Minnesota utilities to provide 80 percent carbon-free energy by 2030, 90 percent carbon-free energy by 2035 and 100 percent carbon-free energy by 2040. The law utilizes renewable energy credits as the means to demonstrate compliance with both the carbon-free and renewable standards, includes an off-ramp provision that enables the MPUC to protect reliability and customer costs through modification or delay of either the renewable energy standard, the carbon-free standard, or both, and streamlines development and construction of wind energy projects and transmission in Minnesota. The Company is evaluating the law to identify challenges and opportunities it could present.

Regulated Operations. Minnesota Power’s long-term strategy is to be the leading electric energy provider in northeastern Minnesota by providing safe, reliable and cost-competitive electric energy, while complying with environmental permit conditions and renewable energy requirements. Keeping the cost of energy production competitive enables Minnesota Power to effectively compete in the wholesale power markets and minimizes retail rate increases to help maintain customer viability. As part of maintaining cost competitiveness, Minnesota Power intends to reduce its exposure to possible future carbon and GHG legislation by reshaping its generation portfolio, over time, to reduce its reliance on coal. In 2021, Minnesota Power announced its vision of delivering 100 percent carbon-free energy by 2050. We will monitor and review proposed environmental regulations and may challenge those that add considerable cost with limited environmental benefit. Minnesota Power will continue to pursue customer growth opportunities and cost recovery rider approvals for transmission, renewable and environmental investments, as well as work with regulators to earn a fair rate of return.

2024 Minnesota General Rate Case. On November 1, 2023, Minnesota Power filed a retail rate increase request with the MPUC seeking an average increase of approximately 12.00 percent for retail customers, net of rider revenue incorporated into base rates. The rate filing seeks a return on equity of 10.30 percent and a 53.00 percent equity ratio. On an annualized basis, the requested final rate increase would generate approximately $89 million in additional revenue. In separate orders dated December 19, 2023, the MPUC accepted the filing as complete and approved an annual interim rate increase of approximately $64 million, net of rider revenue, beginning January 1, 2024, subject to refund. We cannot predict the level of final rates that may be authorized by the MPUC.

On May 3, 2024, Minnesota Power entered into a settlement agreement with the Minnesota Department of Commerce, Minnesota Office of the Attorney General, Residential Utilities Division, and Large Power Intervenors to settle the retail rate increase request. The settlement agreement is subject to approval by the MPUC. As part of the settlement agreement, the parties have agreed on all issues, including an overall rate increase of $33.97 million, net of rider revenue and amounts transferring to the fuel adjustment clause, a return on equity of 9.78 percent, all non-financial items and cost allocation. As a result of the settlement, Minnesota Power recorded a reserve for an interim rate refund of $5.5 million pre-tax as of March 31, 2024, which is subject to MPUC approval of the settlement agreement and Minnesota Power’s refund calculation. We expect estimated reserves for interim rate refunds for the full year in 2024 to be approximately $24 million pre-tax.

2024 Wisconsin General Rate Case. On March 29, 2024, SWL&P filed a rate increase request for its electric, gas and water utilities with the PSCW. The filing seeks an overall return on equity of 10.00 percent and a 55.00 percent equity ratio. On an annualized basis, the requested change would increase revenue by approximately 5.90 percent for retail customers and generate an estimated $7.3 million of additional revenue. The change to SWL&P customers’ rates will be determined by the PSCW later this year. Any rate adjustments are anticipated to become effective in January 2025.

Solar Energy Request For Proposals. On October 2, 2023, Minnesota Power filed a notice with the MPUC of its intent to issue a request for proposals for up to 300 MW of solar energy resources. Minnesota Power issued the request for proposals on November 15, 2023, which were accepted through January 17, 2024. The proposals are currently being evaluated.

Wind Energy Request For Proposals. On December 15, 2023, Minnesota Power filed a notice with the MPUC of its intent to issue a request for proposals for up to 400 MW of wind energy resources. Minnesota Power issued the request for proposals on February 15, 2024, which were accepted through April 11, 2024.

ALLETE, Inc. First Quarter 2024 Form 10-Q

35

OUTLOOK (Continued)

Industrial Customers.

Industrial Customers. Electric power is one of several key inputs in the taconite mining, paper, pulp and secondary wood products, pipeline and other industries. Approximately 54 percent of our regulated utility kWh sales in the three months ended March 31, 2024, were made to our industrial customers (53 percent in the three months ended March 31, 2023).

Taconite.

USS Corporation. USS Corporation’s Minntac and Keetac plants are large power industrial customers of Minnesota Power. These plants have the combined capability to produce approximately 22 million tons of iron ore pellets annually which includes 4 million tons of direct-reduced grade pellets.

On December 18, 2023, USS Corporation announced it entered into a definitive agreement in which Nippon Steel will acquire all of the shares of USS Corporation. On April 12, 2024, USS Corporation shareholders approved the proposed acquisition. USS Corporation expects the transaction to close in the second half of 2024, subject to regulatory approvals, at which time USS Corporation stated it will continue to operate under the U.S. Steel brand name and will maintain its headquarters in Pittsburgh, Pennsylvania.

Paper, Pulp and Secondary Wood Products.

ST Paper. ST Paper, a Large Power Customer of Minnesota Power, announced on January 3, 2024, that it had entered into an agreement to sell the Duluth Mill to Sofidel, a privately held Italian multinational company that is currently the seventh largest manufacturer of tissue paper in the world. Sofidel completed the acquisition of the Duluth Mill in the first quarter of 2024.

Transmission.

Investment in ATC. ATC’s most recent 10-year transmission assessment, which covers the years 2023 through 2032, identifies a need for between $6.6 billion and $8.1 billion in transmission system investments. These investments by ATC, if undertaken, are expected to be funded through a combination of internally generated cash, debt and investor contributions. As opportunities arise, we plan to make additional investments in ATC through general capital calls based upon our pro rata ownership interest in ATC.

North Plains Connector Development Agreement. In December 2023, ALLETE and Grid United LLC, an independent transmission company, signed development agreements for the North Plains Connector project. The project is a new, approximately 400-mile high-voltage direct-current (HVDC) transmission line from central North Dakota, to Colstrip, Montana that will be the first transmission connection between three regional U.S. electric energy markets: MISO, the Western Interconnection and the Southwest Power Pool. This new link, open to all sources of electric generation, would create 3,000 MW of transfer capacity between the middle of the country and the West Coast, easing congestion on the transmission system, increasing resiliency and reliability in all three energy markets, and enabling fast sharing of renewable energy across a vast area with diverse weather patterns. The project capital cost is expected to be approximately $3.2 billion. ALLETE expects to pursue up to 35 percent ownership and would oversee the line’s operation. The companies began project permitting in 2023 as they work toward a planned in-service date as early as 2029, pending regulatory and other necessary approvals.

Duluth Loop Reliability Project. In October 2021, Minnesota Power submitted an application for a certificate of need for the Duluth Loop Reliability Project. This transmission project was proposed to enhance reliability in and around Duluth, Minnesota. The project includes the construction of a new 115-kV transmission line; construction of an approximately one-mile extension of an existing 230-kV transmission line; and upgrades to several substations. A certificate of need was granted and a route permit was issued by the MPUC on April 3, 2023. The Duluth Loop Reliability Project is expected to be completed and in service by late 2026 to early 2027, with an estimated cost of $50 million to $70 million.

ALLETE, Inc. First Quarter 2024 Form 10-Q

36

OUTLOOK (Continued)

Transmission (Continued)

HVDC Transmission System Project. On June 1, 2023, Minnesota Power submitted an application for a certificate of need and route permit with the MPUC to replace aging critical infrastructure and modernize the terminal stations of its HVDC transmission line. Minnesota Power uses the 465-mile, 250-kV HVDC transmission line that runs from Center, North Dakota, to Duluth, Minnesota, to transport wind energy from North Dakota while gradually phasing out coal-based electricity delivered to its system over this transmission line from Square Butte’s lignite coal-fired generating unit. The HVDC transmission system project is expected to improve reliability of the transmission system, improve system resiliency, expand the operating capacity of the HVDC terminals, and replace critical infrastructure. Pending regulatory approvals in Minnesota and North Dakota, construction could begin as early as 2024, with an in-service date expected between 2028 and 2030. The project is estimated to cost between $800 million and $900 million. On October 18, 2023, the U.S. Department of Energy awarded a $50 million grant to Minnesota Power for this project, which will be used to prepare the HVDC transmission system for future expansion and help reduce project costs to customers. In addition, this project was awarded $15 million in state funding as part of an energy and climate budget bill passed by the Minnesota Legislature in 2023. Further, Minnesota Power’s application to the Minnesota Department of Commerce (DOC) State Competitiveness Fund Match Program received notification the DOC is reserving $10 million as a cost share for the project. In total, Minnesota Power has been awarded $75 million in federal and state dollars in support of the project.

Northland Reliability Project. Minnesota Power and Great River Energy announced in July 2022 their intent to build a 150-mile, 345-kV transmission line, connecting northern Minnesota to central Minnesota to support continued reliability in the Upper Midwest. Great River Energy, a wholesale electric power cooperative, and Minnesota Power filed a Notice of Intent to Construct, Own and Maintain the transmission line with the MPUC in August 2022. This joint project is part of a portfolio of transmission projects approved in July 2022 by MISO as part of the first phase of its Long Range Transmission Plan. Planning for the approximately $970 million to $1,350 million transmission line is in its early stages with the route anticipated to generally follow existing rights of way in an established power line corridor. The MPUC will determine the final route as well as cost recovery for Minnesota Power’s approximately 50 percent estimated share of the project. On August 4, 2023, Minnesota Power and Great River Energy submitted an application for a certificate of need and route permit with the MPUC. On March 13, 2024, Minnesota Power submitted a filing with the FERC requesting to recover on construction work in progress related to this project from Minnesota Power’s wholesale customers. Subject to regulatory approvals, the transmission line is expected to be in service in 2030.

Big Stone South Transmission Project. Northern States Power, Great River Energy, Minnesota Power, Otter Tail Power Company, and Missouri River Energy Resources (Project Developers) announced in July 2022 their intent to build a 150-mile, 345-kV transmission line to improve reliability in North Dakota and South Dakota, and western and central Minnesota. This joint project is part of a portfolio of transmission projects approved in July 2022 by MISO as part of the first phase of its Long Range Transmission Plan. A Notice of Intent to Construct, Own and Maintain the transmission line was filed with the MPUC in October 2022. On September 29, 2023, the Project Developers submitted an application for a certificate of need and route permit with the MPUC. The project is in its early stages and is expected to cost between $600 million and $700 million. The MPUC will determine the final route for the Minnesota portion as well as cost recovery for Minnesota Power’s approximately $20 million estimated share of the project. On March 13, 2024, Minnesota Power submitted a filing with the FERC requesting to recover on construction work in progress related to this project from Minnesota Power’s wholesale customers. Subject to regulatory approvals, the transmission line is expected to be in service in 2027.

ALLETE Clean Energy.

ALLETE Clean Energy will pursue growth through acquisitions or project development. ALLETE Clean Energy is targeting acquisitions of existing operating portfolios which have a mix of long-term PSAs in place and/or available for repowering and recontracting. Further, ALLETE Clean Energy will evaluate actions that will lead to the addition of complimentary clean energy products and services. At this time, ALLETE Clean Energy is focused on actions that will optimize its clean energy project portfolio of operating and development projects, which may include recontracting, repowering, entering into partnerships and divestitures along with continued acquisitions or development of new projects including wind, solar, energy storage or storage ready facilities across North America.

Since September 20, 2023, a substation and the transmission lines feeding that substation located near ALLETE Clean Energy’s Caddo wind energy facility, and operated by another party, have experienced a forced outage. This forced outage has increased congestion experienced by the Caddo wind energy facility and is expected to have a negative impact on ALLETE Clean Energy’s results in the first half of 2024. We will continue to monitor this development for timing of repairs and impact going forward.

ALLETE, Inc. First Quarter 2024 Form 10-Q

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OUTLOOK (Continued)

Corporate and Other.

Corporate and Other includes New Energy, a renewable energy development company, BNI Energy, our coal mining operations in North Dakota and ALLETE Properties, our legacy Florida real estate investment, along with our investment in Nobles 2, South Shore Energy, our non-rate regulated, Wisconsin subsidiary developing NTEC, other business development and corporate expenditures, unallocated interest expense, a small amount of non-rate base generation, land in Minnesota, and earnings on cash and investments.

LIQUIDITY AND CAPITAL RESOURCES

Liquidity Position. ALLETE is well-positioned to meet the Company’s liquidity needs. As of March 31, 2024, we had cash and cash equivalents of $32.0 million, $248.6 million in available consolidated lines of credit, 2.1 million original issue shares of common stock available for issuance through a distribution agreement with Lampert Capital Markets and a debt-to-capital ratio of 35 percent. Pursuant to the Merger Agreement, ALLETE has agreed, subject to certain exceptions, to, and to cause each of its subsidiaries to, conduct its business in the ordinary course, consistent with past practice, from the date of the Merger Agreement until the effective time of the Merger, and not to take certain actions prior to the closing of the Merger without the prior written consent of Alloy Parent (which consent shall not be unreasonably withheld, conditioned or delayed, except where ALLETE seeks Alloy Parent’s consent to enter into a material new line of business or cease operations of an existing material line of business). (See Note 11. Subsequent Event – Agreement and Plan of Merger.)

Capital Structure. ALLETE’s capital structure is as follows:

	March 31, 2024	%	December 31, 2023	%
Millions
ALLETE Equity	$2,823.0	54	$2,809.6	54
Non-Controlling Interest in Subsidiaries	585.5	11	597.0	11
Short-Term and Long-Term Debt (a)	1,797.3	35	1,799.4	35
Redeemable Non-Controlling Interest	0.5	—	0.5	—
	$5,206.3	100	$5,206.5	100

(a)Excludes unamortized debt issuance costs.

Cash Flows. Selected information from the Consolidated Statement of Cash Flows is as follows:

For the Three Months Ended March 31,	2024	2023
Millions
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	$79.4	$40.2
Cash Flows provided by (used in)
Operating Activities	60.1	92.4
Investing Activities	(60.8)	(74.7)
Financing Activities	(38.4)	(18.3)
Change in Cash, Cash Equivalents and Restricted Cash	(39.1)	(0.6)
Cash, Cash Equivalents and Restricted Cash at End of Period	$40.3	$39.6

Operating Activities. Cash provided by operating activities was lower in 2024 compared to 2023 reflecting higher cash contributions to defined benefit pension in 2024, and also decreased due to the timing of recovery under Minnesota Power’s fuel adjustment clause.

Investing Activities. Cash used in investing activities was lower in 2024 compared to 2023 reflecting fewer payments for additions to property, plant and equipment compared to 2023.

Financing Activities. Cash used in financing activities in 2024 reflected lower proceeds from the issuance of long-term debt compared to 2023.

ALLETE, Inc. First Quarter 2024 Form 10-Q

38

LIQUIDITY AND CAPITAL RESOURCES (Continued)

Working Capital. Additional working capital, if and when needed, generally is provided by consolidated bank lines of credit and the issuance of securities, including long-term debt, common stock and commercial paper. As of March 31, 2024, we had consolidated bank lines of credit aggregating $362.0 million ($423.1 million as of December 31, 2023), the majority of which expire in January 2027. (See Note 5. Short-Term and Long-Term Debt.) We had $19.4 million outstanding in standby letters of credit and $94.0 million outstanding draws under our lines of credit as of March 31, 2024 ($19.4 million in standby letters of credit and $34.1 million outstanding draws as of December 31, 2023). As of March 31, 2024, we also had $130.7 million outstanding in standby letters of credit under other credit facility agreements.

In addition, as of March 31, 2024, we had 2.6 million original issue shares of our common stock available for issuance through Invest Direct, our direct stock purchase and dividend reinvestment plan, and 2.1 million original issue shares of common stock available for issuance through a distribution agreement with Lampert Capital Markets. (See Securities.) The amount and timing of future sales of our securities will depend upon market conditions and our specific needs.

Securities. During the three months ended March 31, 2024, we issued 0.1 million shares of common stock through Invest Direct, the Employee Stock Purchase Plan, and the Retirement Savings and Stock Ownership Plan, resulting in net proceeds of $2.0 million (0.1 million shares were issued for the three months ended March 31, 2023, resulting in net proceeds of $3.3 million).

Financial Covenants. See Note 5. Short-Term and Long-Term Debt for information regarding our financial covenants.

Pension and Other Postretirement Benefit Plans. Management considers various factors when making funding decisions, such as regulatory requirements, actuarially determined minimum contribution requirements and contributions required to avoid benefit restrictions for the defined benefit pension plans. (See Note 9. Pension and Other Postretirement Benefit Plans.)

Off-Balance Sheet Arrangements. Off-balance sheet arrangements are summarized in our 2023 Form 10-K, with additional disclosure in Note 6. Commitments, Guarantees and Contingencies.

Credit Ratings. Access to reasonably priced capital markets is dependent in part on credit and ratings. Our securities have been rated by S&P Global Ratings and by Moody’s. Rating agencies use both quantitative and qualitative measures in determining a company’s credit rating. These measures include business risk, liquidity risk, competitive position, capital mix, financial condition, predictability of cash flows, management strength and future direction. Some of the quantitative measures can be analyzed through a few key financial ratios, while the qualitative ones are more subjective. Our current credit ratings are listed in the following table:

Credit Ratings	S&P Global Ratings (a)	Moody’s
Issuer Credit Rating	BBB	Baa1
Commercial Paper	A-2	P-2
First Mortgage Bonds	(b)	A2

(a)    On May 7, 2024, S&P Global Ratings revised its outlook on ALLETE to negative from stable and affirmed all of its ratings on ALLETE. S&P Global Ratings cited the possibility for higher leverage and weaker financial measures because of the Merger as its rationale for issuing the negative outlook.

(b)    Not rated by S&P Global Ratings.

The disclosure of these credit ratings is not a recommendation to buy, sell or hold our securities. Ratings are subject to revision or withdrawal at any time by the assigning rating organization. Each rating should be evaluated independently of any other rating.

Capital Requirements. For the three months ended March 31, 2024, capital expenditures totaled $51.8 million ($58.4 million for the three months ended March 31, 2023). The expenditures were primarily made in the Regulated Operations segment.

ALLETE, Inc. First Quarter 2024 Form 10-Q

39

OTHER

Environmental Matters.

Our businesses are subject to regulation of environmental matters by various federal, state and local authorities. A number of regulatory changes to the Clean Air Act, the Clean Water Act and various waste management requirements have been promulgated by both the EPA and state authorities over the past several years. Minnesota Power’s facilities are subject to additional requirements under many of these regulations. Minnesota Power is reshaping its generation portfolio, over time, to reduce its reliance on coal, has installed cost-effective emission control technology, and advocates for sound science and policy during rulemaking implementation. (See Note 6. Commitments, Guarantees and Contingencies.)

Employees.

As of March 31, 2024, ALLETE had 1,583 employees, of which 1,544 were full-time.

Minnesota Power and SWL&P have an aggregate of 492 employees covered under collective bargaining agreements, of which most are members of International Brotherhood of Electrical Workers (IBEW) Local 31. The current labor agreements with IBEW Local 31 expire on April 30, 2026, for Minnesota Power and January 31, 2027, for SWL&P.

BNI Energy has 179 employees, of which 129 are subject to a labor agreement with IBEW Local 1593. The current labor agreement with IBEW Local 1593 expires on March 31, 2026.

NEW ACCOUNTING PRONOUNCEMENTS

New accounting pronouncements are discussed in Note 1. Operations and Significant Accounting Policies.

ITEM 3.  QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

SECURITIES INVESTMENTS

Available-for-Sale Securities. As of March 31, 2024, our available-for-sale securities portfolio consisted primarily of securities held in other postretirement plans to fund employee benefits.

COMMODITY PRICE RISK

Our regulated utility operations incur costs for power and fuel (primarily coal and related transportation) in Minnesota, and power and natural gas purchased for resale in our regulated service territory in Wisconsin. Minnesota Power’s exposure to price risk for these commodities is significantly mitigated by the current ratemaking process and regulatory framework, which allows recovery of fuel costs in excess of those included in base rates or distribution of savings in fuel costs to ratepayers. SWL&P’s exposure to price risk for natural gas is significantly mitigated by the current ratemaking process and regulatory framework, which allows the commodity cost to be passed through to customers. We seek to prudently manage our customers’ exposure to price risk by entering into contracts of various durations and terms for the purchase of power and coal and related transportation costs (Minnesota Power), and natural gas (SWL&P).

POWER MARKETING

Minnesota Power’s power marketing activities consist of: (1) purchasing energy in the wholesale market to serve its regulated service territory when energy requirements exceed generation output; and (2) selling excess available energy and purchased power. From time to time, Minnesota Power may have excess energy that is temporarily not required by retail and municipal customers in our regulated service territory. Minnesota Power actively sells any excess energy to the wholesale market to optimize the value of its generating facilities.

We are exposed to credit risk primarily through our power marketing activities. We use credit policies to manage credit risk, which includes utilizing an established credit approval process and monitoring counterparty limits.

ALLETE, Inc. First Quarter 2024 Form 10-Q

40

ITEM 3.  QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK (Continued)

INTEREST RATE RISK

We are exposed to risks resulting from changes in interest rates as a result of our issuance of variable rate debt. We manage our interest rate risk by varying the issuance and maturity dates of our fixed rate debt, limiting the amount of variable rate debt, and continually monitoring the effects of market changes in interest rates. We may also enter into derivative financial instruments, such as interest rate swaps, to mitigate interest rate exposure. Interest rates on variable rate long-term debt are reset on a periodic basis reflecting prevailing market conditions. Based on the variable rate debt outstanding as of March 31, 2024, an increase of 100 basis points in interest rates would impact the amount of pre-tax interest expense by $1.2 million. This amount was determined by considering the impact of a hypothetical 100 basis point increase to the average variable interest rate on the variable rate debt outstanding as of March 31, 2024.

ITEM 4.  CONTROLS AND PROCEDURES

Evaluation of Disclosure Controls and Procedures. As of March 31, 2024, evaluations were performed, under the supervision and with the participation of management, including our principal executive officer and principal financial officer, on the effectiveness of the design and operation of ALLETE’s disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) of the Securities Exchange Act of 1934 (Exchange Act)). Based upon those evaluations, our principal executive officer and principal financial officer have concluded that such disclosure controls and procedures are effective to provide assurance that information required to be disclosed in ALLETE’s reports filed or submitted under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and such information is accumulated and communicated to our management, including our principal executive officer and principal financial officer, to allow timely decisions regarding required disclosure.

Changes in Internal Controls. There has been no change in our internal control over financial reporting that occurred during our most recent fiscal quarter that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

PART II.  OTHER INFORMATION

ITEM 1.  LEGAL PROCEEDINGS

For information regarding material legal and regulatory proceedings, see Note 4. Regulatory Matters and Note 9. Commitments, Guarantees and Contingencies to the Consolidated Financial Statements in our 2023 Form 10-K and Note 2. Regulatory Matters and Note 6. Commitments, Guarantees and Contingencies herein. Such information is incorporated herein by reference.

ITEM 1A.  RISK FACTORS

Our 2023 Form 10-K includes a detailed discussion of our risk factors. The information presented below updates, and should be read in conjunction with, the risk factors disclosed in Part I, Item 1A. Risk Factors of our 2023 Form 10-K.

Risks Relating to the Merger

On May 5, 2024, ALLETE entered into the Merger Agreement. (See Note 11. Subsequent Event – Agreement and Plan of Merger.)

ALLETE, Inc. First Quarter 2024 Form 10-Q

41

ITEM 1A.  RISK FACTORS (Continued)

There is no assurance when or if the Merger will be completed.

Consummation of the Merger is subject to various closing conditions, including: (1) approval of the shareholders of ALLETE; (2) receipt of all required regulatory approvals without the imposition of a Burdensome Condition; (3) absence of any law or order prohibiting the consummation of the Merger; (4) subject to materiality qualifiers, the accuracy of each party’s representations and warranties; (5) each party’s compliance in all material respects with its obligations and covenants under the Merger Agreement; and (6) the absence of a material adverse effect with respect to the Company. The Merger Agreement also contains certain termination rights for both ALLETE and Alloy Parent, including if the Merger is not consummated by August 5, 2025 (subject to extension for an additional two successive three-month periods if all of the conditions to closing, other than the conditions related to obtaining regulatory approvals, have been satisfied). There can be no assurance that the conditions to completion of the Merger will be satisfied or waived or that other events will not intervene to delay or result in the failure to close the proposed Merger. The Merger Agreement also provides for certain termination rights for each of ALLETE and Alloy Parent. If the Merger Agreement is terminated, there may be various material, adverse consequences to the Company, including that the Company could be required to pay Alloy Parent a termination fee of $116 million under certain specified circumstances.

The announcement and pendency of the Merger, during which the Company is subject to certain operating restrictions, could have an adverse effect on the Company’s businesses, results of operations, financial condition or cash flows.

The announcement and pendency of the Merger could disrupt the Company’s businesses, and uncertainty about the effect of the Merger may have an adverse effect on the Company. These uncertainties could affect existing employee relationships, disrupt the business of the Company, and could cause suppliers, vendors, partners, lenders and others that deal with the Company to: (1) defer entering into contracts with the Company; or (2) making other decisions concerning the Company or seek to change or cancel existing business relationships with the Company.

The Merger Agreement also requires the Company to obtain Parent’s consent prior to taking certain specified actions while the Merger is pending. These restrictions may prevent the Company from pursuing otherwise attractive business opportunities or making other changes to its business prior to the completion of the Merger.

The Company will incur substantial transaction fees and costs in connection with the Merger.

The Company has incurred transaction costs of $1.2 million after-tax through March 31, 2024, and expects to incur additional material expenses in connection with the Merger and completion of the transactions contemplated by the Merger Agreement. Further, even if the proposed Merger is not completed, the Company will need to pay certain costs relating to the proposed Merger incurred prior to the date the proposed Merger was abandoned, such as legal, accounting, financial advisory, filing and printing fees.

We may be the target of securities class action and derivative lawsuits which could result in substantial costs and may delay or prevent the Merger from being completed.

Securities class action lawsuits and derivative lawsuits are often brought against companies that have entered into merger agreements. Even if the lawsuits are without merit, defending against these claims can result in substantial costs to us and divert management time and resources. Additionally, if a plaintiff is successful in obtaining an injunction prohibiting consummation of the Merger, then that injunction may delay or prevent the Merger from being completed.

ITEM 2.  UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS

None.

ITEM 3.  DEFAULTS UPON SENIOR SECURITIES

None.

ALLETE, Inc. First Quarter 2024 Form 10-Q

42

ITEM 4.  MINE SAFETY DISCLOSURES

The Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank Act) requires issuers to include in periodic reports filed with the SEC certain information relating to citations or orders for violations of standards under the Federal Mine Safety and Health Act of 1977 (Mine Safety Act). Information concerning mine safety violations or other regulatory matters required by Section 1503(a) of the Dodd-Frank Act and this Item are included in Exhibit 95 to this Form 10-Q.

ITEM 5.  OTHER INFORMATION

Trading Plans. During the quarter ended March 31, 2024, no director or officer of the Company adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(a) of Regulation S-K.

ITEM 6.  EXHIBITS

Exhibit	Description
2	Agreement and Plan of Merger by and among ALLETE, Inc., Alloy Parent LLC and Alloy Merger Sub LLC, dated as of May 5, 2024 (filed as Exhibit 2.1 to the May 6, 2024, Form 8-K, File No. 1-3548).*
4	Forty-Fifth Supplemental Indenture, dated as of April 1, 2024, between ALLETE, Inc. and The Bank of New York Mellon, as corporate trustee, and Sherma Thomas, as co-trustee.
31(a)	Rule 13a-14(a)/15d-14(a) Certification by the Chief Executive Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
31(b)	Rule 13a-14(a)/15d-14(a) Certification by the Chief Financial Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
32	Section 1350 Certification of Periodic Report by the Chief Executive Officer and the Chief Financial Officer Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.
95	Mine Safety.
99	ALLETE News Release dated May 9, 2024, announcing 2024 first quarter earnings. (This exhibit has been furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, except as shall be expressly set forth by specific reference in such filing.)
101.INS	XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document.
101.SCH	XBRL Schema
101.CAL	XBRL Calculation
101.DEF	XBRL Definition
101.LAB	XBRL Label
101.PRE	XBRL Presentation
104	Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)

*Schedules and exhibits have been omitted pursuant to Item 601(b)(2) of Regulation S-K. A copy of any omitted schedules will be furnished supplementally to the SEC upon request; provided, however, that the parties may request confidential treatment pursuant to Rule 24b-2 of the Exchange Act for any document so furnished.

ALLETE agrees to furnish to the SEC upon request any instrument with respect to long-term debt that ALLETE has not filed as an exhibit pursuant to the exemption provided by Item 601(b)(4)(iii)(A) of Regulation S-K.

ALLETE, Inc. First Quarter 2024 Form 10-Q

43

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

	ALLETE, INC.
May 9, 2024	/s/ Steven W. Morris
	Steven W. Morris
	Senior Vice President and Chief Financial Officer
	(Principal Financial Officer and Principal Accounting Officer)

ALLETE, Inc. First Quarter 2024 Form 10-Q

44

EX-4

Exhibit 4

SUPPLEMENTAL INDENTURE

ALLETE, Inc.

(formerly Minnesota Power & Light Company
and formerly Minnesota Power, Inc.)

TO

THE BANK OF NEW YORK MELLON

(formerly The Bank of New York

(formerly Irving Trust Company))

AND

SHERMA THOMAS

(successor to Richard H. West, J. A. Austin, E. J. McCabe, D. W. May, J. A. Vaughan, W. T. Cunningham, Douglas J. MacInnes, Ming Ryan, Philip L. Watson, Andres Serrano, Eva Waite and Janet Lee)

As Trustees under ALLETE, Inc.’s Mortgage and Deed of Trust dated as of September 1, 1945

Forty-fifth Supplemental Indenture
Providing, among other things, for

First Mortgage Bonds, 5.72% Series due April 30, 2039
(Sixty-fifth Series),

Dated as ofApril 1, 2024

1

Exhibit 4

FORTY-FIFTH SUPPLEMENTAL INDENTURE

THIS INDENTURE, dated as of April 1, 2024, by and between ALLETE, Inc. (formerly Minnesota Power & Light Company and formerly Minnesota Power, Inc.), a corporation of the State of Minnesota, whose post office address is 30 West Superior Street, Duluth, Minnesota 55802 (hereinafter sometimes called the “Company”), and The Bank of New York Mellon (formerly The Bank of New York (formerly Irving Trust Company)), a corporation of the State of New York, whose post office address is 240 Greenwich Street, New York, New York 10286 (hereinafter sometimes called the “Corporate Trustee”), and Sherma Thomas (successor to Richard H. West, J. A. Austin, E. J. McCabe, D. W. May, J. A. Vaughan, W. T. Cunningham, Douglas J. MacInnes, Ming Ryan, Philip L. Watson, Andres Serrano, Eva Waite and Janet Lee), whose post office address is c/o The Bank of New York Mellon, 240 Greenwich Street, New York, New York 10286 (said Sherma Thomas being hereinafter sometimes called the “Co-Trustee” and the Corporate Trustee and the Co-Trustee being hereinafter together sometimes called the “Trustees”), as Trustees under the Mortgage and Deed of Trust, dated as of September 1, 1945, between the Company and Irving Trust Company and Richard H. West, as Trustees, securing bonds issued and to be issued as provided therein (hereinafter sometimes called the “Mortgage”), reference to which Mortgage is hereby made, this indenture (hereinafter sometimes called the “Forty-fifth Supplemental Indenture”) being supplemental thereto:

Whereas, the Mortgage was filed and recorded in various official records in the State of Minnesota; and

Whereas, an instrument, dated as of October 16, 1957, was executed and delivered under which J. A. Austin succeeded Richard H. West as Co-Trustee under the Mortgage, and such instrument was filed and recorded in various official records in the State of Minnesota; and

Whereas, an instrument, dated as of April 4, 1967, was executed and delivered under which E. J. McCabe in turn succeeded J. A. Austin as Co-Trustee under the Mortgage, and such instrument was filed and recorded in various official records in the State of Minnesota; and

Whereas, under the Sixth Supplemental Indenture, dated as of August 1, 1975, to which reference is hereinafter made, D. W. May in turn succeeded E. J. McCabe as Co-Trustee under the Mortgage; and

Whereas, an instrument, dated as of June 25, 1984, was executed and delivered under which J. A. Vaughan in turn succeeded D. W. May as Co-Trustee under the Mortgage, and such instrument was filed and recorded in various official records in the State of Minnesota; and

Whereas, an instrument, dated as of July 27, 1988, was executed and delivered under which W. T. Cunningham in turn succeeded J. A. Vaughan as Co-Trustee under the Mortgage, and such instrument was filed and recorded in various official records in the State of Minnesota; and

Whereas, on May 12, 1998, the Company filed Amended and Restated Articles of Incorporation with the Secretary of State of the State of Minnesota changing its name from Minnesota Power & Light Company to Minnesota Power, Inc. effective May 27, 1998; and

Whereas, an instrument, dated as of April 15, 1999, was executed and delivered under which Douglas J. MacInnes in turn succeeded W. T. Cunningham as Co-Trustee under the Mortgage, and such instrument was filed and recorded in various official records in the State of Minnesota; and

2

Exhibit 4

Whereas, on May 8, 2001, the Company filed Amended and Restated Articles of Incorporation with the Secretary of State of the State of Minnesota changing its name from Minnesota Power, Inc. to ALLETE, Inc.; and

Whereas, under the Thirty-second Supplemental Indenture, dated as of August 1, 2010, to which reference is hereinafter made, Ming Ryan in turn succeeded Douglas J. MacInnes as Co-Trustee under the Mortgage; and

Whereas, an instrument, dated as of August 1, 2012, was executed and delivered under which Philip L. Watson in turn succeeded Ming Ryan as Co-Trustee under the Mortgage effective at the close of business on August 6, 2012, and such instrument was filed and recorded in various official records in the State of Minnesota and the State of North Dakota; and

Whereas, an instrument, dated as of July 31, 2015, was executed and delivered under which Andres Serrano in turn succeeded Philip L. Watson as Co-Trustee under the Mortgage effective at the close of business on August 14, 2015, and such instrument was filed and recorded in various official records in the State of Minnesota and the State of North Dakota; and

Whereas, an instrument, dated as of July 29, 2021, was executed and delivered under which Eva Waite in turn succeeded Andres Serrano as Co-Trustee under the Mortgage effective at the close of business on July 29, 2021, and such instrument was filed and recorded in various official records in the State of Minnesota and the State of North Dakota; and

Whereas, an instrument, dated as of April 27, 2022, was executed and delivered under which Janet Lee in turn succeeded Eva Waite as Co-Trustee under the Mortgage effective at the close of business on April 27, 2022, and such instrument was filed and recorded in various official records in the State of Minnesota and the State of North Dakota; and

Whereas, an instrument, dated as of March 25, 2024, was executed and delivered under which Sherma Thomas in turn succeeded Janet Lee as Co-Trustee under the Mortgage effective at the close of business on March 25, 2024, and such instrument was filed and recorded in various official records in the State of Minnesota and the State of North Dakota; and

Whereas, by the Mortgage the Company covenanted, among other things, that it would execute and deliver such supplemental indenture or indentures and such further instruments and do such further acts as might be necessary or proper to carry out more effectually the purposes of the Mortgage and to make subject to the lien of the Mortgage any property thereafter acquired and intended to be subject to the lien thereof; and

Whereas, for said purposes, among others, the Company executed and delivered the following indentures supplemental to the Mortgage:

Designation	Dated as of
First Supplemental Indenture	March 1, 1949
Second Supplemental Indenture	July 1, 1951
Third Supplemental Indenture	March 1, 1957
Fourth Supplemental Indenture	January 1, 1968
Fifth Supplemental Indenture	April 1, 1971
Sixth Supplemental Indenture	August 1, 1975
Seventh Supplemental Indenture	September 1, 1976
Eighth Supplemental Indenture	September 1, 1977

3

Exhibit 4

Designation	Dated as of
Ninth Supplemental Indenture	April 1, 1978
Tenth Supplemental Indenture	August 1, 1978
Eleventh Supplemental Indenture	December 1, 1982
Twelfth Supplemental Indenture	April 1, 1987
Thirteenth Supplemental Indenture	March 1, 1992
Fourteenth Supplemental Indenture	June 1, 1992
Fifteenth Supplemental Indenture	July 1, 1992
Sixteenth Supplemental Indenture	July 1, 1992
Seventeenth Supplemental Indenture	February 1, 1993
Eighteenth Supplemental Indenture	July 1, 1993
Nineteenth Supplemental Indenture	February 1, 1997
Twentieth Supplemental Indenture	November 1, 1997
Twenty-first Supplemental Indenture	October 1, 2000
Twenty-second Supplemental Indenture	July 1, 2003
Twenty-third Supplemental Indenture	August 1, 2004
Twenty-fourth Supplemental Indenture	March 1, 2005
Twenty-fifth Supplemental Indenture	December 1, 2005
Twenty-sixth Supplemental Indenture	October 1, 2006
Twenty-seventh Supplemental Indenture	February 1, 2008
Twenty-eighth Supplemental Indenture	May 1, 2008
Twenty-ninth Supplemental Indenture	November 1, 2008
Thirtieth Supplemental Indenture	January 1, 2009
Thirty-first Supplemental Indenture	February 1, 2010
Thirty-second Supplemental Indenture	August 1, 2010
Thirty-third Supplemental Indenture	July 1, 2012
Thirty-fourth Supplemental Indenture	April 1, 2013
Thirty-fifth Supplemental Indenture	March 1, 2014
Thirty-sixth Supplemental Indenture	June 1, 2014
Thirty-seventh Supplemental Indenture	September 1, 2014
Thirty-eighth Supplemental Indenture Thirty-ninth Supplemental Indenture Fortieth Supplemental Indenture Forty-first Supplemental Indenture Forty-second Supplemental Indenture Forty-third Supplemental Indenture Forty-fourth Supplemental Indenture	September 1, 2015 April 1, 2018 March 1, 2019 August 1, 2020 September 1, 2021 August 1, 2022 April 1, 2023

which supplemental indentures were filed and recorded in various official records in the State of Minnesota and the State of North Dakota; and

Whereas, the Company has heretofore issued, in accordance with the provisions of the Mortgage, as heretofore supplemented, the following series of First Mortgage Bonds:

Series	Principal Amount   Issued	Principal Amount Outstanding
3-1/8% Series due 1975	$26,000,000	None
3-1/8% Series due 1979	4,000,000	None
3-5/8% Series due 1981	10,000,000	None

4

Exhibit 4

Series	Principal Amount   Issued	Principal Amount Outstanding
4-3/4% Series due 1987	12,000,000	None
6-1/2% Series due 1998	18,000,000	None
8-1/8% Series due 2001	23,000,000	None
10-1/2% Series due 2005	35,000,000	None
8.70% Series due 2006	35,000,000	None
8.35% Series due 2007	50,000,000	None
9-1/4% Series due 2008	50,000,000	None
Pollution Control Series A	111,000,000	None
Industrial Development Series A	2,500,000	None
Industrial Development Series B	1,800,000	None
Industrial Development Series C	1,150,000	None
Pollution Control Series B	13,500,000	None
Pollution Control Series C	2,000,000	None
Pollution Control Series D	3,600,000	None
7-3/4% Series due 1994	55,000,000	None
7-3/8% Series due March 1, 1997	60,000,000	None
7-3/4% Series due June 1, 2007	55,000,000	None
7-1/2% Series due August 1, 2007	35,000,000	None
Pollution Control Series E	111,000,000	None
7% Series due March 1, 2008	50,000,000	None
6-1/4% Series due July 1, 2003	25,000,000	None
7% Series due February 15, 2007	60,000,000	None
6.68% Series due November 15, 2007	20,000,000	None
Floating Rate Series due October 20, 2003	250,000,000	None
Collateral Series A	255,000,000	None
Pollution Control Series F	111,000,000	None
5.28% Series due August 1, 2020	35,000,000	None
5.69% Series due March 1, 2036	50,000,000	50,000,000
5.99% Series due February 1, 2027	60,000,000	60,000,000
4.86% Series due April 1, 2013	60,000,000	None
6.02% Series due May 1, 2023	75,000,000	None
6.94% Series due January 15, 2014	18,000,000	None
7.70% Series due January 15, 2016	20,000,000	None
8.17% Series due January 15, 2019	42,000,000	None
4.85% Series due April 15, 2021	15,000,000	None
5.10% Series due April 15, 2025	30,000,000	30,000,000
6.00% Series due April 15, 2040	35,000,000	35,000,000
4.90% Series due October 15, 2025	30,000,000	30,000,000
5.82% Series due April 15, 2040	45,000,000	45,000,000
3.20% Series due July 15, 2026	75,000,000	75,000,000
4.08% Series due July 15, 2042	85,000,000	85,000,000
1.83% Series due April 15, 2018	50,000,000	None
3.30% Series due October 15, 2028	40,000,000	40,000,000
4.21% Series due October 15, 2043	60,000,000	60,000,000
3.69% Series due March 15, 2024	60,000,000	None
4.95% Series due March 15, 2044	40,000,000	40,000,000
3.40% Series due July 15, 2022	75,000,000	None

5

Exhibit 4

Series	Principal Amount   Issued	Principal Amount Outstanding
5.05% Series due July 15, 2044	40,000,000	40,000,000
3.02% Series due September 15, 2021	60,000,000	None
3.74% Series due September 15, 2029	50,000,000	50,000,000
4.39% Series due September 15, 2044	50,000,000	50,000,000
2.80% Series due September 15, 2020	40,000,000	None
3.86% Series due September 16, 2030 4.07% Series due April 16, 2048 4.08% Series due March 1, 2029 4.47% Series due March 1, 2049 2.50% Series due August 1, 2030 3.30% Series due August 1, 2050 2.79% Series due September 1, 2031 4.54% Series due August 9, 2032 4.98% Series due April 27, 2033	60,000,000 60,000,000 70,000,000 30,000,000 46,000,000 94,000,000 100,000,000 75,000,000 125,000,000	60,000,000 60,000,000 70,000,000 30,000,000 46,000,000 94,000,000    100,000,000  75,000,000 125,000,000

which bonds are also hereinafter sometimes called bonds of the First through Sixty-fourth Series, respectively; and

Whereas, Section 8 of the Mortgage provides that the form of each series of bonds (other than the First Series) issued thereunder and of coupons to be attached to coupon bonds of such series shall be established by Resolution of the Board of Directors of the Company and that the form of such series, as established by said Board of Directors, shall specify the descriptive title of the bonds and various other terms thereof, and may also contain such provisions not inconsistent with the provisions of the Mortgage as the Board of Directors may, in its discretion, cause to be inserted therein expressing or referring to the terms and conditions upon which such bonds are to be issued and/or secured under the Mortgage; and

Whereas, Section 120 of the Mortgage provides, among other things, that any power, privilege or right expressly or impliedly reserved to or in any way conferred upon the Company by any provision of the Mortgage, whether such power, privilege or right is in any way restricted or is unrestricted, may (to the extent permitted by law) be in whole or in part waived or surrendered or subjected to any restriction if at the time unrestricted or to additional restriction if already restricted, and the Company may enter into any further covenants, limitations or restrictions for the benefit of any one or more series of bonds issued thereunder, or the Company may cure any ambiguity contained therein, or in any supplemental indenture, or may establish the terms and provisions of any series of bonds (other than said First Series) by an instrument in writing executed and acknowledged by the Company in such manner as would be necessary to entitle a conveyance of real estate to record in all of the states in which any property at the time subject to the lien of the Mortgage shall be situated; and

Whereas, the Company now desires to create one new series of bonds and (pursuant to the provisions of Section 120 of the Mortgage) to add to its covenants and agreements contained in the Mortgage, as heretofore supplemented, certain other covenants and agreements to be observed by it and to alter and amend in certain respects the covenants and provisions contained in the Mortgage, as heretofore supplemented; and

Whereas, the execution and delivery by the Company of this Forty-fifth Supplemental Indenture, and the terms of the bonds of the Sixty-fifth Series, hereinafter referred to, have been duly authorized by the Board of Directors of the Company by appropriate resolutions of said Board of Directors;

6

Exhibit 4

Now, Therefore, This Indenture Witnesseth:

That the Company, in consideration of the premises and of One Dollar to it duly paid by the Trustees at or before the ensealing and delivery of these presents, the receipt whereof is hereby acknowledged, and in further evidence of assurance of the estate, title and rights of the Trustees and in order further to secure the payment of both the principal of and interest and premium, if any, on the bonds from time to time issued under the Mortgage, as heretofore supplemented, according to their tenor and effect and the performance of all the provisions of the Mortgage (including any instruments supplemental thereto and any modification made as in the Mortgage provided) and of said bonds, hereby grants, bargains, sells, releases, conveys, assigns, transfers, mortgages, pledges, sets over and confirms (subject, however, to Excepted Encumbrances) unto The Bank of New York Mellon and Sherma Thomas, as Trustees under the Mortgage, and to their successor or successors in said trust, and to said Trustees and their successors and assigns forever, all property, real, personal and mixed, of the kind or nature specifically mentioned in the Mortgage, as heretofore supplemented, or of any other kind or nature acquired by the Company after the date of the execution and delivery of the Mortgage, as heretofore supplemented (except any herein or in the Mortgage, as heretofore supplemented, expressly excepted), now owned or, subject to the provisions of subsection (I) of Section 87 of the Mortgage, hereafter acquired by the Company (by purchase, consolidation, merger, donation, construction, erection or in any other way) and wheresoever situated, including (without in anywise limiting or impairing by the enumeration of the same the scope and intent of the foregoing or of any general description contained in this Forty-fifth Supplemental Indenture) all lands, power sites, flowage rights, water rights, water locations, water appropriations, ditches, flumes, reservoirs, reservoir sites, canals, raceways, dams, dam sites, aqueducts, and all other rights or means for appropriating, conveying, storing and supplying water; all rights of way and roads; all plants for the generation of electricity by steam, water and/or other power; all power houses, gas plants, street lighting systems, standards and other equipment incidental thereto, telephone, radio and television systems, air-conditioning systems and equipment incidental thereto, water works, water systems, steam heat and hot water plants, substations, lines, service and supply systems, bridges, culverts, tracks, ice or refrigeration plants and equipment, offices, buildings and other structures and the equipment thereof; all machinery, engines, boilers, dynamos, electric, gas and other machines, regulators, meters, transformers, generators, motors, electrical, gas and mechanical appliances, conduits, cables, water, steam heat, gas or other pipes, gas mains and pipes, service pipes, fittings, valves and connections, pole and transmission lines, wires, cables, tools, implements, apparatus, furniture and chattels; all municipal and other franchises, consents or permits; all lines for the transmission and distribution of electric current, gas, steam heat or water for any purpose including towers, poles, wires, cables, pipes, conduits, ducts and all apparatus for use in connection therewith; all real estate, lands, easements, servitudes, licenses, permits, franchises, privileges, rights of way and other rights in or relating to real estate or the occupancy of the same and (except as herein or in the Mortgage, as heretofore supplemented, expressly excepted) all the right, title and interest of the Company in and to all other property of any kind or nature appertaining to and/or used and/or occupied and/or enjoyed in connection with any property hereinbefore or in the Mortgage, as heretofore supplemented, described.

Together with all and singular the tenements, hereditaments, prescriptions, servitudes and appurtenances belonging or in anywise appertaining to the aforesaid property or any part thereof, with the reversion and reversions, remainder and remainders and (subject to the provisions of Section 57 of the Mortgage) the tolls, rents, revenues, issues, earnings, income, product and profits thereof, and all the estate, right, title and interest and claim whatsoever, at law as well as in equity, which the Company now has or may hereafter acquire in and to the aforesaid property and franchises and every part and parcel thereof.

It is hereby agreed by the Company that, subject to the provisions of subsection (I) of Section 87 of the Mortgage, all the property, rights, and franchises acquired by the Company (by purchase,

7

Exhibit 4

consolidation, merger, donation, construction, erection or in any other way) after the date hereof, except any herein or in the Mortgage, as heretofore supplemented, expressly excepted, shall be and are as fully granted and conveyed hereby and by the Mortgage and as fully embraced within the lien hereof and the lien of the Mortgage as if such property, rights and franchises were now owned by the Company and were specifically described herein or in the Mortgage and conveyed hereby or thereby.

Provided that the following are not and are not intended to be now or hereafter granted, bargained, sold, released, conveyed, assigned, transferred, mortgaged, hypothecated, affected, pledged, set over or confirmed hereunder and are hereby expressly excepted from the lien and operation of this Forty-fifth Supplemental Indenture and from the lien and operation of the Mortgage, namely: (1) cash, shares of stock, bonds, notes and other obligations and other securities not hereafter specifically pledged, paid, deposited, delivered or held under the Mortgage or covenanted so to be; (2) merchandise, equipment, apparatus, materials or supplies held for the purpose of sale or other disposition in the usual course of business; fuel, oil and similar materials and supplies consumable in the operation of any of the properties of the Company; all aircraft, rolling stock, trolley coaches, buses, motor coaches, automobiles and other vehicles and materials and supplies held for the purpose of repairing or replacing (in whole or part) any of the same; all timber, minerals, mineral rights and royalties; (3) bills, notes and accounts receivable, judgments, demands and choses in action, and all contracts, leases and operating agreements not specifically pledged under the Mortgage or covenanted so to be; the Company’s contractual rights or other interest in or with respect to tires not owned by the Company; (4) the last day of the term of any lease or leasehold which may hereafter become subject to the lien of the Mortgage; (5) electric energy, gas, steam, ice, and other materials or products generated, manufactured, produced or purchased by the Company for sale, distribution or use in the ordinary course of its business; (6) the Company’s franchise to be a corporation; and (7) any property heretofore released pursuant to any provisions of the Mortgage; provided, however, that the property and rights expressly excepted from the lien and operation of this Forty-fifth Supplemental Indenture and from the lien and operation of the Mortgage in the above subdivisions (2) and (3) shall (to the extent permitted by law) cease to be so excepted in the event and as of the date that either or both of the Trustees or a receiver or trustee shall enter upon and take possession of the Mortgaged and Pledged Property in the manner provided in Article XIII of the Mortgage by reason of the occurrence of a Default as defined in Section 65 thereof.

To have and to hold all such properties, real, personal and mixed, granted, bargained, sold, released, conveyed, assigned, transferred, mortgaged, pledged, set over or confirmed by the Company as aforesaid, or intended so to be, unto the Trustees and their successors and assigns forever.

In trust nevertheless, for the same purposes and upon the same terms, trusts and conditions and subject to and with the same provisos and covenants as are set forth in the Mortgage, as supplemented, this Forty-fifth Supplemental Indenture being supplemental thereto.

And it is hereby covenanted by the Company that all the terms, conditions, provisos, covenants and provisions contained in the Mortgage, as heretofore supplemented, shall affect and apply to the property hereinbefore described and conveyed and to the estate, rights, obligations and duties of the Company and Trustees and the beneficiaries of the trust with respect to said property, and to the Trustees and their successors in the trust in the same manner and with the same effect as if said property had been owned by the Company at the time of the execution of the Mortgage, and had been specifically and at length described in and conveyed to said Trustees by the Mortgage as a part of the property therein stated to be conveyed.

The Company further covenants and agrees to and with the Trustees and their successors in said trust under the Mortgage as follows:

8

Exhibit 4

ARTICLE I

Sixty-fifth Series of Bonds

Section 1. There shall be a series of bonds designated “5.72% Series due April 30, 2039” (herein sometimes referred to as the “Sixty-fifth Series”), each of which shall also bear the descriptive title “First Mortgage Bond”, and the form thereof, which shall be established by Resolution of the Board of Directors of the Company, shall contain suitable provisions with respect to the matters hereinafter in this Section specified. Bonds of the Sixty-fifth Series shall be dated as in Section 10 of the Mortgage provided, mature on April 30, 2039 (the “Sixty-fifth Series Stated Maturity”), be issued as fully registered bonds in denominations of One Thousand Dollars and, at the option of the Company, in any multiple or multiples of One Thousand Dollars (the exercise of such option to be evidenced by the execution and delivery thereof) and bear interest from April 23, 2024 (computed on the basis of a 360-day year of twelve thirty-day months) at the rate of 5.72% per annum, payable semi-annually on April 30 and October 30 of each year, commencing October 30, 2024, the principal of and interest on each said bond to be payable at the office or agency of the Company in the Borough of Manhattan, The City of New York, in such coin or currency of the United States of America as at the time of payment is legal tender for public and private debts.

Any payment of principal of or interest on any bond of the Sixty-fifth Series that is due on a date other than a Business Day shall be made on the next succeeding Business Day without including the additional days elapsed in the computation of the interest payable on such next succeeding Business Day; provided that if the maturity date of any such bond of the Sixty-fifth Series is a date other than a Business Day, the payment otherwise due on such maturity date shall be made on the next succeeding Business Day and shall include the additional days elapsed in the computation of interest payable on such next succeeding Business Day.

(I)    Optional Prepayment. At any time prior to January 30, 2039 (three months prior to the Sixty-fifth Series Stated Maturity) the Company may, at its option, upon notice as provided below, prepay at any time all, or from time to time any part of, the bonds of the Sixty-fifth Series at 100% of the principal amount so prepaid, and the Make-Whole Amount determined for the Settlement Date specified by the Company in such notice with respect to such principal amount. The Company will give each registered owner of bonds of the Sixty-fifth Series written notice (by first class mail or such other method as may be agreed upon by the Company and such registered owner) of each optional prepayment under this subsection (I) mailed or otherwise given not less than 30 days and not more than 60 days prior to the date fixed for such prepayment, to each such registered owner at his, her or its last address appearing on the registry books. Each such notice shall specify the Settlement Date (which shall be a Business Day), the aggregate principal amount of the bonds of the Sixty-fifth Series to be prepaid on such date, the principal amount of each bond held by such registered owner to be prepaid (determined in accordance with subsection (II) of this section), and the interest to be paid on the Settlement Date with respect to such principal amount being prepaid, and shall be accompanied by a certificate signed by a Senior Financial Officer as to the estimated Make-Whole Amount due in connection with such prepayment (calculated as if the date of such notice were the date of the prepayment), setting forth the details of such computation. Two Business Days prior to such Settlement Date, the Company shall send to each registered owner of bonds of the Sixty-fifth Series (by first class mail or by such other method as may be agreed upon by the Company and such registered owner) a certificate signed by a Senior Financial Officer specifying the calculation of such Make-Whole Amount as of the specified Settlement Date. As promptly as practicable after the giving of the notice and the sending of the certificates provided in this subsection, the Company shall provide a copy of each to the Corporate Trustee. The Trustees shall be under no duty to inquire into, may conclusively presume the correctness of, and shall be fully protected in relying upon the information set forth in any such notice or certificate.

9

Exhibit 4

At any time on or after January 30, 2039, the bonds of the Sixty-fifth Series will be redeemable at the option of the Company, in whole or in part, on not less than 30 nor more than 60 days’ notice prior to the Settlement Date, at a redemption price equal to 100% of the principal amount of the bonds of the Sixty-fifth Series to be redeemed, plus accrued and unpaid interest thereon to the Settlement Date.

The bonds of the Sixty-fifth Series are not otherwise subject to voluntary or optional prepayment.

    (II)    Allocation of Partial Prepayments. In the case of each partial prepayment of the bonds of the Sixty-fifth Series, the principal amount of the bonds of the Sixty-fifth Series to be prepaid shall be allocated by the Company among all of the bonds of the Sixty-fifth Series at the time outstanding in proportion, as nearly as practicable, to the respective unpaid principal amounts thereof not theretofore called for prepayment.

    (III)     Maturity; Surrender, Etc.     In the case of each notice of prepayment of bonds of the Sixty-fifth Series pursuant to this section, if cash sufficient to pay the principal amount to be prepaid on the Settlement Date (which shall be a Business Day), together with interest on such principal amount accrued to such date and the applicable Make-Whole Amount, if any, is not paid as agreed upon by the Company and each registered owner of the affected bonds, or, to the extent that there is no such agreement entered into with one or more such owners, deposited with the Corporate Trustee on or before the Settlement Date, then such notice of prepayment shall be of no effect. If such cash is so paid or deposited, such principal amount of the bonds of the Sixty-fifth Series shall be deemed paid for all purposes and interest on such principal amount shall cease to accrue. In case the Company pays any registered owner pursuant to an agreement with that registered owner, the Company shall notify the Corporate Trustee as promptly as practicable of such agreement and payment, and shall furnish the Corporate Trustee with a copy of such agreement; in case the Company deposits any cash with the Corporate Trustee, the Company shall provide therewith a list of the registered owners and the amount of such cash each registered owner is to receive. The Trustees shall be under no duty to inquire into, may conclusively presume the correctness of, and shall be fully protected in relying upon the information set forth in any such notice, list or agreement, and shall not be chargeable with knowledge of any of the contents of any such agreement. Any bond prepaid in full shall be surrendered to the Company or the Corporate Trustee for cancellation on or before the Settlement Date or, with respect to cash deposited with the Corporate Trustee, before payment of such cash by the Corporate Trustee; any bond prepaid in part shall be surrendered to the Company or the Corporate Trustee on or before the Settlement Date (unless otherwise agreed between the Company and the registered owner) or, with respect to cash deposited with the Corporate Trustee before payment of such cash by the Corporate Trustee, for a substitute bond in the principal amount remaining unpaid.

    (IV)    Make-Whole Amount.

The term “Make-Whole Amount” means, with respect to any bond of the Sixty-fifth Series, an amount equal to the excess, if any, of the Discounted Value of the Remaining Scheduled Payments with respect to the Called Principal of such bond of the Sixty-fifth Series over the amount of such Called Principal, provided that the Make-Whole Amount may in no event be less than zero. For the purposes of determining the Make-Whole Amount, the following terms have the following meanings:

“Business Day” means any day other than a Saturday, a Sunday or a day on which commercial banks in New York City are required or authorized to be closed.

“Called Principal” means, with respect to any bond of the Sixty-fifth Series, the principal of such bond that is to be prepaid pursuant to subsection (I) of this section.

10

Exhibit 4

“Discounted Value” means, with respect to the Called Principal of any bond of the Sixty-fifth Series, the amount obtained by discounting all Remaining Scheduled Payments with respect to such Called Principal from their respective scheduled due dates to the Settlement Date with respect to such Called Principal, in accordance with accepted financial practice and at a discount factor (applied on the same periodic basis as that on which interest on the bonds of the Sixty-fifth Series is payable) equal to the Reinvestment Yield with respect to such Called Principal.

“Reinvestment Yield” means, with respect to the Called Principal of any bond of the Sixty-fifth Series, the sum of (a) 0.50% plus (b) the yield to maturity implied by the “Ask Yield(s)” reported as of 10:00 a.m. (New York City time) on the second Business Day preceding the Settlement Date with respect to such Called Principal, on the display designated as “Page PX1” (or such other display as may replace Page PX1) on Bloomberg Financial Markets for the most recently issued actively traded on-the-run benchmark U.S. Treasury securities (“Reported”) having a maturity equal to the Remaining Average Life of such Called Principal as of such Settlement Date. If there are no such U.S. Treasury securities Reported having a maturity equal to such Remaining Average Life, then such implied yield to maturity will be determined by (i) converting U.S. Treasury bill quotations to bond equivalent yields in accordance with accepted financial practice and (ii) interpolating linearly between the “Ask Yields” Reported for the applicable most recently issued actively traded on-the-run benchmark U.S. Treasury securities with the maturities (1) closest to and greater than such Remaining Average Life and (2) closest to and less than such Remaining Average Life. The Reinvestment Yield shall be rounded to the number of decimal places as appears in the interest rate of the applicable bond of the Sixty-fifth Series.

If such yields are not Reported or the yields Reported as of such time are not ascertainable (including by way of interpolation), then “Reinvestment Yield” means, with respect to the Called Principal of any bond of the Sixty-fifth Series, the sum of (x) 0.50% plus (y) the yield to maturity implied by the U.S. Treasury constant maturity yields reported, for the latest day for which such yields have been so reported as of the second Business Day preceding the Settlement Date with respect to such Called Principal, in Federal Reserve Statistical Release H.15 (or any comparable successor publication) for the U.S. Treasury constant maturity having a term equal to the Remaining Average Life of such Called Principal as of such Settlement Date. If there is no such U.S. Treasury constant maturity having a term equal to such Remaining Average Life, such implied yield to maturity will be determined by interpolating linearly between (1) the U.S. Treasury constant maturity so reported with the term closest to and greater than such Remaining Average Life and (2) the U.S. Treasury constant maturity so reported with the term closest to and less than such Remaining Average Life. The Reinvestment Yield shall be rounded to the number of decimal places as appears in the interest rate of the applicable bond of the Sixty-fifth Series.

“Remaining Average Life” means, with respect to any Called Principal, the number of years obtained by dividing (i) such Called Principal into (ii) the sum of the products obtained by multiplying (a) the principal component of each Remaining Scheduled Payment with respect to such Called Principal by (b) the number of years, computed on the basis of a 360-day year comprised of twelve 30-day months and calculated to two decimal places, that will elapse between the Settlement Date with respect to such Called Principal and the scheduled due date of such Remaining Scheduled.

“Remaining Scheduled Payments” means, with respect to the Called Principal of any bond of the Sixty-fifth Series, all payments of such Called Principal and interest thereon that would be due after the Settlement Date with respect to such Called Principal if no payment of such Called Principal were made prior to its scheduled due, provided that if such Settlement Date is not a date on which interest payments are due to be made under the terms of the bonds of the Sixty-fifth Series, then the amount of the next succeeding scheduled interest payment will be reduced by the amount of interest accrued to such Settlement Date and required to be paid on such Settlement Date pursuant to subsection (I) of this section.

11

Exhibit 4

“Settlement Date” means, with respect to the Called Principal of any bond of the Sixty-fifth Series, the date on which such Called Principal is to be prepaid pursuant to subsection (I) of this section.

“Senior Financial Officer” means the chief financial officer, principal accounting officer, treasurer or comptroller of the Company.

(V)    At the option of the registered owner, any bonds of the Sixty-fifth Series, upon surrender thereof for cancellation at the office or agency of the Company in the Borough of Manhattan, The City of New York, together with a written instrument of transfer wherever required by the Company duly executed by the registered owner or by his duly authorized attorney, shall (subject to the provisions of Section 12 of the Mortgage) be exchangeable for a like aggregate unpaid principal amount of bonds of the same series of other authorized denominations.

Bonds of the Sixty-fifth Series shall be transferable (subject to the provisions of Section 12 of the Mortgage) at the office or agency of the Company in the Borough of Manhattan, The City of New York. The Company shall not be required to make transfers or exchanges of bonds of the Sixty-fifth Series for a period of ten (10) days next preceding any interest payment date for bonds of such series, or next preceding any designation of bonds of said series to be prepaid, and the Company shall not be required to make transfers or exchanges of any bonds of said series designated in whole or in part for prepayment.

Upon any exchange or transfer of bonds of the Sixty-fifth Series, the Company may make a charge therefor sufficient to reimburse it for any tax or taxes or other governmental charge, as provided in Section 12 of the Mortgage, but the Company hereby waives any right to make a charge in addition thereto for any exchange or transfer of bonds of the Sixty-fifth Series.

After the delivery of this Forty-fifth Supplemental Indenture and upon compliance with the applicable provisions of the Mortgage and receipt of consideration therefor by the Company, there shall be an initial issue of bonds of the Sixty-fifth Series for the aggregate principal amount of $100,000,000.

ARTICLE II

Consent to Amendments

Section 1.  Consent to Amendments  Each initial and future holder of bonds of the Sixty-fifth Series, by its acquisition of an interest in such bonds, irrevocably (a) consents to the amendments set forth in Article IV of the Thirty-first Supplemental Indenture, dated as of February 1, 2010, and Article III of this Forty-fifth Supplemental Indenture, without any other or further action by any holder of such bonds, and (b) designates the Corporate Trustee, and its successors, as its proxy with irrevocable instructions to vote and deliver written consents on behalf of such holder in favor of such amendments at any bondholder meeting, in lieu of any bondholder meeting, in any consent solicitation or otherwise.

ARTICLE III

Reservation of Right to Amend Sections 35(a), 99, 101 and 102 of the Mortgage

Section 1. The Company reserves the right, without any vote, consent or other action by the holders of bonds of the Sixty-fifth Series, or any subsequent series, to amend the Mortgage, as herein or heretofore supplemented as follows:

12

Exhibit 4

        (A) to amend Section 35(a) to delete the phrase “having its principal office and place of business in the Borough of Manhattan, The City of New York” and the word “such” at the location in said Section 35(a) at which such word first appears; and

        (B) to amend Sections 99, 101 and 102 to remove all requirements for the publishing of notices of the resignation, removal or appointment of any Trustee and to delete all references to the publication of such notices in the Mortgage, as herein or heretofore supplemented, including deletion of words “the first publication of notice of” in the last sentence of the first paragraph of Section 102.

ARTICLE IV

Miscellaneous Provisions

Section 1. Section 126 of the Mortgage, as heretofore amended, is hereby further amended by adding the words “and April 30, 2039” after the words “and April 27, 2033”.

Section 2. Subject to the amendments provided for in this Forty-fifth Supplemental Indenture, the terms defined in the Mortgage, as heretofore supplemented, shall, for all purposes of this Forty-fifth Supplemental Indenture, have the meanings specified in the Mortgage, as heretofore supplemented.

Section 3. The holders of bonds of the Sixty-fifth Series consent that the Company may, but shall not be obligated to, fix a record date for the purpose of determining the holders of bonds of the Sixty-fifth Series entitled to consent to any amendment, supplement or waiver. If a record date is fixed, those persons who were holders at such record date (or their duly designated proxies), and only those persons, shall be entitled to consent to such amendment, supplement or waiver or to revoke any consent previously given, whether or not such persons continue to be holders after such record date. No such consent shall be valid or effective for more than 90 days after such record date.

Section 4. The Trustees hereby accept the trusts herein declared, provided, created or supplemented and agree to perform the same upon the terms and conditions herein and in the Mortgage set forth and upon the following terms and conditions:

The Trustees shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Forty-fifth Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made by the Company solely. In general, each and every term and condition contained in Article XVII of the Mortgage shall apply to and form part of this Forty-fifth Supplemental Indenture with the same force and effect as if the same were herein set forth in full with such omissions, variations and insertions, if any, as may be appropriate to make the same conform to the provisions of this Forty-fifth Supplemental Indenture.

Section 5. Whenever in this Forty-fifth Supplemental Indenture any party hereto is named or referred to, this shall, subject to the provisions of Articles XVI and XVII of the Mortgage, as heretofore supplemented, be deemed to include the successors or assigns of such party, and all the covenants and agreements in this Forty-fifth Supplemental Indenture contained by or on behalf of the Company, or by or on behalf of the Trustees shall, subject as aforesaid, bind and inure to the benefit of the respective successors and assigns of such party whether so expressed or not.

13

Exhibit 4

Section 6. Nothing in this Forty-fifth Supplemental Indenture, expressed or implied, is intended, or shall be construed, to confer upon, or give to, any person, firm or corporation, other than the parties hereto and the holders of the bonds and coupons Outstanding under the Mortgage, any right, remedy, or claim under or by reason of this Forty-fifth Supplemental Indenture or any covenant, condition, stipulation, promise or agreement hereof, and all the covenants, conditions, stipulations, promises and agreements in this Forty-fifth Supplemental Indenture contained by and on behalf of the Company shall be for the sole and exclusive benefit of the parties hereto, and of the holders of the bonds and of the coupons Outstanding under the Mortgage.

Section 7. This Forty-fifth Supplemental Indenture shall be executed in several counterparts, each of which shall be an original and all of which shall constitute but one and the same instrument.

Section 8. The Company, the mortgagor named herein, by its execution hereof acknowledges receipt of a full, true and complete copy of this Forty-fifth Supplemental Indenture.

14

Exhibit 4

In witness whereof, ALLETE, Inc. has caused its corporate name to be hereunto affixed, and this instrument to be signed and sealed by its President, one of its Vice Presidents, or its Treasurer, and its corporate seal to be attested by its Secretary or one of its Assistant Secretaries for and in its behalf, all in the City of Duluth, Minnesota, and The Bank of New York Mellon has caused its corporate name to be hereunto affixed, and this instrument to be signed by one of its Vice Presidents or one of its Assistant Vice Presidents, and Sherma Thomas has hereunto set her hand, all in The City of New York, as of the day and year first above written.

ALLETE, Inc.

By

Patrick L. Cutshall

Vice President and Corporate Treasurer

Attest:

Margaret A. Thickens

Vice President, Chief Legal Officer

and Corporate Secretary

Trustees’ Signature Pages Follow

15

Exhibit 4

The Bank of New York Mellon,

as Trustee

By

Stacey B. Poindexter

Vice President

Forty-fifth Supplemental Indenture dated as of April 1, 2024

to Mortgage and Deed of Trust dated as of September 1, 1945

Corporate Trustee’s Signature Page

16

Exhibit 4

SHERMA THOMAS

Forty-fifth Supplemental Indenture dated as of April 1, 2024

to Mortgage and Deed of Trust dated as of September 1, 1945

Co-Trustee’s Signature Page

17

Exhibit 4

STATE OF MINNESOTA )

) SS

COUNTY OF ST. LOUIS )

    On this 11th day of April, 2024, the foregoing instrument was acknowledged before me by Patrick L. Cutshall, Vice President and Corporate Treasurer of ALLETE, Inc., a Minnesota corporation, on behalf of the Company.

NOTARIAL STAMP OR SEAL

            ________________________________________

                         Jodi Lumberg

STATE OF MINNESOTA )

) SS

COUNTY OF ST. LOUIS )

    On this 11th day of April, 2024, the foregoing instrument was acknowledged before me by Margaret A. Thickens, Vice President, Chief Legal Officer, and Corporate Secretary of ALLETE, Inc., a Minnesota corporation, on behalf of the Company.

NOTARIAL STAMP OR SEAL

             ________________________________________

                         Jodi Lumberg

18

Exhibit 4

State of New York        )

)  ss:

County of New York        )

On this 15th day of April, 2024, the foregoing instrument was acknowledged before me by Stacey B. Poindexter, a Vice President of The Bank of New York Mellon, the corporation named in the foregoing instrument.

Given under my hand and notarial seal this 15th day of April, 2024.

Rafal Bar

Notary Public, State of New York       

No. 01BA6293822

Qualified in Kings County

Commission Expires January 31st, 2026

19

Exhibit 4

State of New York        )

)  ss:

County of New York        )

On this 11th day of April, 2024, the foregoing instrument was acknowledged before me by Sherma Thomas, the person described in and who executed the foregoing instrument.

Given under my hand and notarial seal this 11th day of April, 2024.

Rafal Bar

Notary Public, State of New York       

No. 01BA6293822

Qualified in Kings County

Commission Expires January 31st, 2026

20

EX-31.A

Exhibit 31(a)

Rule 13a-14(a)/15d-14(a) Certification by the Chief Executive Officer

Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

I, Bethany M. Owen, of ALLETE, Inc. (ALLETE), certify that:

1.I have reviewed this quarterly report on Form 10-Q for the period ended March 31, 2024, of ALLETE;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a.Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b.Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c.Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d.Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a.All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b.Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

May 9, 2024	/s/ Bethany M. Owen
	Bethany M. Owen
	Chair, President and Chief Executive Officer

EX-31.B

Exhibit 31(b)

Rule 13a-14(a)/15d-14(a) Certification by the Chief Financial Officer

Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

I, Steven W. Morris, of ALLETE, Inc. (ALLETE), certify that:

1.I have reviewed this quarterly report on Form 10-Q for the period ended March 31, 2024, of ALLETE;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a.Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b.Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c.Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d.Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions): 

a.All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b.Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

May 9, 2024	/s/ Steven W. Morris
	Steven W. Morris
	Senior Vice President and Chief Financial Officer

EX-32

Exhibit 32

Section 1350 Certification of Periodic Report

By the Chief Executive Officer and Chief Financial Officer

Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002

Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C. Section 1350, each of the undersigned officers of ALLETE, Inc. (ALLETE), does hereby certify that:

1.The Quarterly Report on Form 10-Q of ALLETE for the period ended March 31, 2024, (Report) fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934 (15 U.S.C. 78m); and

2.The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of ALLETE.

May 9, 2024
	/s/ Bethany M. Owen
	Bethany M. Owen
	Chair, President and Chief Executive Officer

May 9, 2024
	/s/ Steven W. Morris
	Steven W. Morris
	Senior Vice President and Chief Financial Officer

This certification shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 or otherwise subject to liability pursuant to that section. Such certification shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Securities Exchange Act of 1934, except to the extent that ALLETE specifically incorporates it by reference.

A signed original of this written statement required by Section 906, or other document authenticating, acknowledging, or otherwise adopting the signature that appears in typed form within the electronic version of this written statement required by Section 906, has been provided to ALLETE and will be retained by ALLETE and furnished to the Securities and Exchange Commission or its staff upon request.

EX-95

Exhibit 95

Mine Safety Disclosure

Mine or Operating Name/MSHA Identification Number

Section 104 S&S Citations (#)

Section 104(b) Orders (#)

Section 104(d) Citations and Orders (#)

Section 110(b)(2) Violations (#)

Section 107(a) Orders (#)

Total Dollar Value of MSHA Assessments Proposed ($)

Total Number of Mining Related Fatalities (#)

Received Notice of Pattern of Violation Under Section 104(e) (yes/no)

Received Notice of Potential to Have Pattern Under Section 104(e) (yes/no)

Legal Actions Pending as of Last Day of Period (#)

Legal Actions Initiated During Period (#)

Legal Actions Resolved During Period (#)

Center Mine / 3200218

2

—

—

—

—

—

—

No

No

—

—

—

For the quarter ended March 31, 2024, BNI Energy, owner of Center Mine, received eight citations under Section 104(a) of the Mine Safety Act, two of which were Section 104 significant and substantial (S&S) citations. For the quarter ended March 31, 2024, BNI Energy paid no penalties for citations closed during the period. For the quarter ended March 31, 2024, there were no citations, orders, violations or notices under Sections 104(b), 104(d), 107(a), 104(e) or 110(b)(2) of the Mine Safety Act and there were no fatalities.

EX-99

		Exhibit 99
	For Release:	May 9, 2024
	Investor Contact:	Vince Meyer
		218-723-3952
NEWS		vmeyer@allete.com

ALLETE, Inc. reports first quarter 2024 earnings

DULUTH, Minn. - ALLETE, Inc. (NYSE: ALE) today reported first quarter 2024 earnings of 88 cents per share on net income of $50.7 million. Last year’s first quarter results were $1.02 per share on net income of $58.2 million. Net income in 2024 includes interim rate refund reserves of 7 cents per share due to Minnesota Power’s rate case settlement, a 6 cent per share negative impact due to warmer winter weather, and 2 cents per share of transaction expenses related to the recently announced merger.

“I am proud of our entire ALLETE team, working diligently on many fronts to execute our Sustainability in Action strategy. We are pleased that Minnesota Power worked collaboratively to reach a balanced resolution to settle the current rate case with all intervening parties, which is subject to approval by the Minnesota Public Utilities Commission,” said ALLETE Chair, President, and Chief Executive Officer Bethany Owen. “In addition, Minnesota Power’s requests for proposals for new solar and wind projects are progressing as planned, ALLETE Clean Energy has begun taking advantage of the Inflation Reduction Act with the sale of production tax credits in the second quarter, and New Energy Equity is executing on its strategy and robust pipeline of projects.”

ALLETE’s Regulated Operations segment, which includes Minnesota Power, Superior Water, Light and Power and the Company’s investment in the American Transmission Company, recorded first quarter 2024 net income of $44.2 million, compared to $40.6 million in the first quarter a year ago. Net income at Minnesota Power was higher primarily due to the implementation of interim rates, net of reserves. Interim rates went into effect on January 1, 2024, and as a result of the rate case settlement, Minnesota Power recorded a reserve of $3.9 million after-tax for the interim rate refund.

ALLETE Clean Energy recorded first quarter 2024 net income of $3.8 million compared to $8.5 million in 2023. Earnings in 2024 reflect impacts from a forced network outage near its Caddo wind energy facility as well as a transformer outage at its Diamond Springs wind energy facility. These decreases were partially offset by lower operating and maintenance expense.

Corporate and Other businesses, which include New Energy, BNI Energy, ALLETE Properties and our investments in renewable energy facilities, recorded net income of $2.7 million in the first quarter of 2024, compared to net income of $9.1 million in 2023. Net income in 2024 reflects lower earnings from Minnesota solar projects as investment tax credits were recognized in 2023, as well as higher income tax and interest expense as compared to 2023. Net income in 2024 also included transaction expenses of $1.2 million after-tax, or 2 cents per share, related to the merger entered into on May 5, 2024, with Canada Pension Plan Investment Board and Global Infrastructure Partners.

Page 1 of 4

ALLETE · 30 West Superior Street, Duluth, Minnesota 55802

“Results for the first quarter of 2024 reflect several items not in our original 2024 guidance, including warmer weather negatively impacting sales to residential and commercial customers and the implementation of interim rate reserves as a result of the rate case settlement," said ALLETE Senior Vice President and Chief Financial Officer Steve Morris. “Excluding these items, results for our Regulated Operations segment were well ahead of our internal expectations. New Energy's financial results were as expected in the first quarter of 2024. ALLETE Clean Energy’s results were lower than our expectations due to lower wind resources and availability, as well as an extended third-party network outage and a transformer outage at ALLETE Clean Energy’s wind energy facilities in Oklahoma.”

Cancellation of Q1 Earnings Conference Call

In light of the announced merger agreement with Canada Pension Plan Investment Board and Global Infrastructure Partners, ALLETE has cancelled its earnings conference call previously scheduled for May 9, 2024, at 10 a.m. Eastern time.

ALLETE is an energy company headquartered in Duluth, Minn. In addition to its electric utilities, Minnesota Power and Superior Water, Light and Power of Wisconsin, ALLETE owns ALLETE Clean Energy, based in Duluth, BNI Energy in Bismarck, N.D., New Energy Equity in Annapolis, MD, and has an eight percent equity interest in the American Transmission Co. More information about ALLETE is available at www.allete.com. ALE-CORP

The statements contained in this release and statements that ALLETE may make orally in connection with this release that are not historical facts, are forward-looking statements. Actual results may differ materially from those projected in the forward-looking statements. These forward-looking statements involve risks and uncertainties and investors are directed to the risks discussed in documents filed by ALLETE with the Securities and Exchange Commission.

ALLETE's press releases and other communications may include certain non-Generally Accepted Accounting Principles (GAAP) financial measures. A "non-GAAP financial measure" is defined as a numerical measure of a company's financial performance, financial position or cash flows that excludes (or includes) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP in the company's financial statements.

Non-GAAP financial measures utilized by the Company include presentations of earnings (loss) per share. ALLETE's management believes that these non-GAAP financial measures provide useful information to investors by removing the effect of variances in GAAP reported results of operations that are not indicative of changes in the fundamental earnings power of the Company's operations. Management believes that the presentation of the non-GAAP financial measures is appropriate and enables investors and analysts to more accurately compare the company's ongoing financial performance over the periods presented.

Page 2 of 4

ALLETE · 30 West Superior Street, Duluth, Minnesota 55802

ALLETE, Inc.

Consolidated Statement of Income

Millions Except Per Share Amounts - Unaudited

	Three Months Ended
	March 31,
	2024	2023
Operating Revenue
Contracts with Customers – Utility	$338.3	$312.6
Contracts with Customers – Non-utility	63.7	251.0
Other – Non-utility	1.3	1.3
Total Operating Revenue	403.3	564.9
Operating Expenses
Fuel, Purchased Power and Gas – Utility	133.5	118.6
Transmission Services – Utility	22.7	20.1
Cost of Sales – Non-utility	24.4	210.5
Operating and Maintenance	91.7	85.7
Depreciation and Amortization	65.0	62.3
Taxes Other than Income Taxes	18.7	19.4
Total Operating Expenses	356.0	516.6
Operating Income	47.3	48.3
Other Income (Expense)
Interest Expense	(20.4)	(19.3)
Equity Earnings	5.5	6.0
Other	8.6	4.1
Total Other Expense	(6.3)	(9.2)
Income Before Income Taxes	41.0	39.1
Income Tax Expense	4.0	1.5
Net Income	37.0	37.6
Net Loss Attributable to Non-Controlling Interest	(13.7)	(20.6)
Net Income Attributable to ALLETE	$50.7	$58.2
Average Shares of Common Stock
Basic	57.6	57.3
Diluted	57.7	57.3
Basic Earnings Per Share of Common Stock	$0.88	$1.02
Diluted Earnings Per Share of Common Stock	$0.88	$1.02
Dividends Per Share of Common Stock	$0.705	$0.68

Consolidated Balance Sheet

Millions - Unaudited

	Mar. 31,	Dec. 31,		Mar. 31,	Dec. 31,
	2024	2023		2024	2023
Assets			Liabilities and Equity
Cash and Cash Equivalents	$32.0	$71.9	Current Liabilities	$260.8	$377.6
Other Current Assets	401.2	396.2	Long-Term Debt	1,772.4	1,679.9
Property, Plant and Equipment – Net	5,009.1	5,013.4	Deferred Income Taxes	195.0	192.7
Regulatory Assets	409.0	425.4	Regulatory Liabilities	564.0	574.0
Equity Investments	333.1	331.2	Defined Benefit Pension and Other Postretirement Benefit Plans	135.4	160.8
Goodwill and Intangibles – Net	155.4	155.4	Other Non-Current Liabilities	268.0	264.3
Other Non-Current Assets	264.8	262.9	Redeemable Non-Controlling Interest	0.5	0.5
			Equity	3,408.5	3,406.6
Total Assets	$6,604.6	$6,656.4	Total Liabilities, Redeemable Non-Controlling Interest and Equity	$6,604.6	$6,656.4

Page 3 of 4

ALLETE · 30 West Superior Street, Duluth, Minnesota 55802

	Three Months Ended
ALLETE, Inc.	March 31,
Income (Loss)	2024	2023
Millions
Regulated Operations	$44.2	$40.6
ALLETE Clean Energy	3.8	8.5
Corporate and Other	2.7	9.1
Net Income Attributable to ALLETE	$50.7	$58.2
Diluted Earnings Per Share	$0.88	$1.02

Statistical Data
Corporate
Common Stock
High	$63.69	$66.64
Low	$55.86	$57.88
Close	$59.64	$64.37
Book Value	$48.95	$47.38

Kilowatt-hours Sold
Millions
Regulated Utility
Retail and Municipal
Residential	306	321
Commercial	338	347
Industrial	1,798	1,658
Municipal	125	128
Total Retail and Municipal	2,567	2,454
Other Power Suppliers	757	696
Total Regulated Utility Kilowatt-hours Sold	3,324	3,150

Regulated Utility Revenue
Millions
Regulated Utility Revenue
Retail and Municipal Electric Revenue
Residential	$46.7	$42.4
Commercial	47.4	44.0
Industrial	158.5	143.4
Municipal	9.0	8.9
Total Retail and Municipal Electric Revenue	261.6	238.7
Other Power Suppliers	40.0	35.9
Other (Includes Water and Gas Revenue)	36.7	38.0
Total Regulated Utility Revenue	$338.3	$312.6

This exhibit has been furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, except as shall be expressly set forth by specific reference in such filing.

Page 4 of 4

ALLETE · 30 West Superior Street, Duluth, Minnesota 55802

XML

Cover	3 Months Ended
	Mar. 31, 2024 shares
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	1-3548
Entity Registrant Name	ALLETE, Inc.
State of Incorporation	MN
Entity Tax Identification Number	41-0418150
Entity Address, Address Line One	30 West Superior Street
Entity Address, City or Town	Duluth
Entity Address, State or Province	MN
Entity Address, Postal Zip Code	55802-2093
City Area Code	218
Local Phone Number	279-5000
Title of 12(b) Security	Common Stock, without par value
Trading Symbol	ALE
Name of Exchange	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	57,666,069
Entity Central Index Key	0000066756
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

XML

Consolidated Balance Sheet Unaudited - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Current Assets
Cash and Cash Equivalents	$ 32.0	$ 71.9
Accounts Receivable (Less Allowance of $1.7 and $1.6)	142.2	137.2
Inventories – Net	182.7	175.4
Prepayments and Other	76.3	83.6
Total Current Assets	433.2	468.1
Property, Plant and Equipment – Net	5,009.1	5,013.4
Regulatory Assets	409.0	425.4
Equity Investments	333.1	331.2
Goodwill and Intangible Assets – Net	155.4	155.4
Other Non-Current Assets	264.8	262.9
Total Assets	6,604.6	6,656.4
Current Liabilities
Accounts Payable	84.2	102.2
Accrued Taxes	62.9	51.0
Accrued Interest	16.3	21.1
Long-Term Debt Due Within One Year	17.2	111.4
Other	80.2	91.9
Total Current Liabilities	260.8	377.6
Long-Term Debt	1,772.4	1,679.9
Deferred Income Taxes	195.0	192.7
Regulatory Liabilities	564.0	574.0
Defined Benefit Pension and Other Postretirement Benefit Plans	135.4	160.8
Other Non-Current Liabilities	268.0	264.3
Total Liabilities	3,195.6	3,249.3
Commitments, Guarantees and Contingencies (Note 6)
Redeemable Non-Controlling Interest	0.5	0.5
Equity
Common Stock Without Par Value, 80.0 Shares Authorized, 57.7 and 57.6 Shares Issued and Outstanding	1,807.4	1,803.7
Accumulated Other Comprehensive Loss	(20.9)	(20.5)
Retained Earnings	1,036.5	1,026.4
Total ALLETE Equity	2,823.0	2,809.6
Non-Controlling Interest in Subsidiaries	585.5	597.0
Total Equity	3,408.5	3,406.6
Total Liabilities, Redeemable Non-Controlling Interest and Equity	$ 6,604.6	$ 6,656.4

XML

Consolidated Balance Sheet Unaudited Parentheticals - USD ($) shares in Millions, $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Accounts Receivable [Abstract]
Accounts Receivable (Less Allowance of $1.7 and $1.6)	$ 1.7	$ 1.6
Common Stock [Abstract]
Common stock, shares authorized (in shares)	80.0	80.0
Common stock, shares outstanding (in shares)	57.7	57.6
Common stock, shares issued (in shares)	57.7	57.6

XML

Consolidated Statement of Income Unaudited - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating Revenue
Contracts with Customers – Utility	$ 338.3	$ 312.6
Contracts with Customers – Non-utility	63.7	251.0
Other – Non-utility	1.3	1.3
Total Operating Revenue	403.3	564.9
Operating Expenses
Fuel, Purchased Power and Gas – Utility	133.5	118.6
Transmission Services – Utility	22.7	20.1
Cost of Sales – Non-utility	24.4	210.5
Operating and Maintenance	91.7	85.7
Depreciation and Amortization	65.0	62.3
Taxes Other than Income Taxes	18.7	19.4
Total Operating Expenses	356.0	516.6
Operating Income	47.3	48.3
Other Income (Expense)
Interest Expense	(20.4)	(19.3)
Equity Earnings	5.5	6.0
Other	8.6	4.1
Total Other Expense	(6.3)	(9.2)
Income Before Income Taxes	41.0	39.1
Income Tax Expense	4.0	1.5
Net Income	37.0	37.6
Net Loss Attributable to Non-Controlling Interest	(13.7)	(20.6)
Net Income Attributable to ALLETE	$ 50.7	$ 58.2
Earnings Per Share [Abstract]
Basic (in shares)	57.6	57.3
Diluted (in shares)	57.7	57.3
Basic Earnings Per Share of Common Stock (in usd per share)	$ 0.88	$ 1.02
Diluted Earnings Per Share of Common Stock (in usd per share)	$ 0.88	$ 1.02

XML

Consolidated Statement of Comprehensive Income Unaudited - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Comprehensive Income [Abstract]
Net Income	$ 37.0	$ 37.6
Other Comprehensive Income (Loss)
Net of Income Tax Expense of $– and $0.1	0.0	0.1
Net of Income Tax Expense of $0.1 and $–	(0.4)	0.0
Total Other Comprehensive Income (Loss)	(0.4)	0.1
Total Comprehensive Income	36.6	37.7
Net Loss Attributable to Non-Controlling Interest	(13.7)	(20.6)
Total Comprehensive Income Attributable to ALLETE	$ 50.3	$ 58.3

XML

Consolidated Statement of Comprehensive Income Unaudited Parentheticals - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Unrealized gain on securities, income tax expense	$ 0.0	$ 0.1
Defined benefit pension and other postretirement benefit plans, income tax expense	$ 0.1	$ 0.0

XML

Consolidated Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating Activities
Net Income	$ 37.0	$ 37.6
Adjustments to Reconcile Net Income to Cash provided by (used in) Operating Activities:
AFUDC – Equity	(1.2)	(0.5)
Loss (Income) on Investments and Property, Plant and Equipment	(0.5)	0.4
Depreciation Expense	65.0	62.3
Amortization of PSAs	(1.3)	(1.3)
Amortization of Other Intangible Assets and Other Assets	1.6	1.9
Deferred Income Tax Benefit	(2.9)	(6.3)
Share-Based and ESOP Compensation Expense	1.7	0.8
Defined Benefit Pension and Other Postretirement Plan Benefit	(3.4)	(0.8)
Fuel Adjustment Clause	4.9	15.3
Bad Debt Expense	0.3	0.3
Provision for Interim Rate Refund	5.5	5.1
Changes in Operating Assets and Liabilities
Accounts Receivable	(5.5)	17.3
Inventories	(7.3)	109.0
Prepayments and Other	6.7	11.0
Accounts Payable	(10.4)	(10.7)
Other Current Liabilities	(19.8)	(142.2)
Cash Contributions to Defined Benefit Pension Plans	(25.0)	(6.5)
Changes in Regulatory and Other Non-Current Assets	9.1	(0.7)
Changes in Regulatory and Other Non-Current Liabilities	5.6	0.4
Cash provided by Operating Activities	60.1	92.4
Investing Activities
Proceeds from Sale of Available-for-sale Securities	1.4	0.0
Payments for Purchase of Available-for-sale Securities	(1.5)	0.0
Payments for Equity Method Investments	(1.6)	(0.8)
Additions to Property, Plant and Equipment	(60.6)	(70.0)
Other Investing Activities	1.5	(3.9)
Cash used in Investing Activities	(60.8)	(74.7)
Financing Activities
Proceeds from Issuance of Common Stock	2.0	3.3
Proceeds from Issuance of Short-Term and Long-Term Debt	156.0	238.5
Repayments of Short-Term and Long-Term Debt	(158.0)	(227.8)
Proceeds from Non-Controlling Interest in Subsidiaries – Net	2.7	6.7
Distributions to Non-Controlling Interest	(0.5)	(0.3)
Dividends on Common Stock	(40.6)	(38.8)
Other Financing Activities	0.0	0.1
Cash used in Financing Activities	(38.4)	(18.3)
Change in Cash, Cash Equivalents and Restricted Cash	(39.1)	(0.6)
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	79.4	40.2
Cash, Cash Equivalents and Restricted Cash at End of Period	$ 40.3	$ 39.6

XML

Consolidated Statement of Equity - USD ($) $ in Millions	Total	Common Stock	Accumulated Other Comprehensive Loss	Retained Earnings	Non-Controlling Interest in Subsidiaries
Balance, Beginning of Period at Dec. 31, 2022		$ 1,781.5	$ (24.4)	$ 934.8	$ 656.4
Consolidated Statement of Equity [Roll Forward]
Common Stock Issued		4.1
Unrealized Gain on Debt Securities	$ 0.1		0.1
Defined Benefit Pension and Other Postretirement Plans	0.0		0.0
Net Income Attributable to ALLETE	58.2			58.2
Common Stock Dividends				(38.8)
Proceeds from Non-Controlling Interest in Subsidiaries – Net					6.7
Net Loss Attributable to Non-Controlling Interest	20.6				(20.6)
Distributions to Non-Controlling Interest					(0.3)
Balance, End of Period at Mar. 31, 2023	3,357.7	1,785.6	(24.3)	954.2	642.2
Balance, Beginning of Period at Dec. 31, 2022	0.0
Redeemable Non-Controlling Interest
Proceeds from Non-Controlling Interest in Subsidiaries	0.0
Net Loss Attributable to Non-Controlling Interest	0.0
Total Redeemable Non-Controlling Interest at Mar. 31, 2023	$ 0.0
Redeemable Non-Controlling Interest
Dividends Per Share of Common Stock (in usd per share	$ 0.6775
Balance, Beginning of Period at Dec. 31, 2023	$ 3,406.6	1,803.7	(20.5)	1,026.4	597.0
Consolidated Statement of Equity [Roll Forward]
Common Stock Issued		3.7
Unrealized Gain on Debt Securities	0.0		0.0
Defined Benefit Pension and Other Postretirement Plans	(0.4)		(0.4)
Net Income Attributable to ALLETE	50.7			50.7
Common Stock Dividends				(40.6)
Proceeds from Non-Controlling Interest in Subsidiaries – Net					0.0
Net Loss Attributable to Non-Controlling Interest	13.7				(11.0)
Distributions to Non-Controlling Interest					(0.5)
Balance, End of Period at Mar. 31, 2024	3,408.5	$ 1,807.4	$ (20.9)	$ 1,036.5	$ 585.5
Balance, Beginning of Period at Dec. 31, 2023	0.5
Redeemable Non-Controlling Interest
Proceeds from Non-Controlling Interest in Subsidiaries	2.7
Net Loss Attributable to Non-Controlling Interest	(2.7)
Total Redeemable Non-Controlling Interest at Mar. 31, 2024	$ 0.5
Redeemable Non-Controlling Interest
Dividends Per Share of Common Stock (in usd per share	$ 0.705

XML

Operations and Significant Accounting Policies

3 Months Ended

Mar. 31, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Operations and Significant Accounting Policies

OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES

Subsequent Events. The Company performed an evaluation of subsequent events for potential recognition and disclosure through the date of the financial statements issuance.

On May 5, 2024, ALLETE entered into the Merger Agreement. (See Note 11. Subsequent Event – Agreement and Plan of Merger.)

Cash, Cash Equivalents and Restricted Cash. We consider all investments purchased with original maturities of three months or less to be cash equivalents. As of March 31, 2024, restricted cash amounts included in Prepayments and Other on the Consolidated Balance Sheet include collateral deposits required under an ALLETE Clean Energy loan. The restricted cash amounts included in Other Non-Current Assets represent collateral deposits required under an ALLETE Clean Energy loan agreement as well as PSAs. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheet that aggregate to the amounts presented in the Consolidated Statement of Cash Flows.

Cash, Cash Equivalents and Restricted Cash	March 31, 2024	December 31, 2023	March 31, 2023	December 31, 2022
Millions
Cash and Cash Equivalents	$32.0	$71.9	$29.9	$36.4
Restricted Cash included in Prepayments and Other	5.9	5.1	7.4	1.5
Restricted Cash included in Other Non-Current Assets	2.4	2.4	2.3	2.3
Cash, Cash Equivalents and Restricted Cash on the Consolidated Statement of Cash Flows	$40.3	$79.4	$39.6	$40.2

Inventories – Net. Inventories are stated at the lower of cost or net realizable value. Inventories in our Regulated Operations segment are carried at an average cost or first-in, first-out basis. Inventories in our ALLETE Clean Energy segment and Corporate and Other businesses are carried at an average cost, first-in, first-out or specific identification basis.

Inventories – Net	March 31, 2024	December 31, 2023
Millions
Fuel (a)	$30.2	$27.2
Materials and Supplies	119.0	115.7
Renewable Energy Facilities Under Development (b)	33.5	32.5
Total Inventories – Net	$182.7	$175.4

(a)    Fuel consists primarily of coal inventory at Minnesota Power.

(b)    Renewable Energy Facilities Under Development as of March 31, 2024, consists primarily of project costs related to renewable energy development projects at New Energy.

Goodwill. The aggregate carrying amount of goodwill was $154.9 million as of March 31, 2024 ($154.9 million as of December 31, 2023). There have been no changes to goodwill by reportable segment for the quarter and three months ended March 31, 2024.

NOTE 1. OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES (Continued)

Other Non-Current Assets	March 31, 2024	December 31, 2023
Millions
Other Postretirement Benefit Plans	$104.6	$106.3
Contract Assets (a)	17.9	18.5
Operating Lease Right-of-use Assets	11.3	10.7
ALLETE Properties	10.7	10.8
Restricted Cash	2.4	2.4
Finance Lease Right-of-use Assets	2.0	2.1
Other	115.9	112.1
Total Other Non-Current Assets	$264.8	$262.9

(a)    Contract Assets consist of payments made to customers as an incentive to execute or extend service agreements. The payments are being amortized over the term of the respective agreements as a reduction to revenue.     

Other Current Liabilities	March 31, 2024	December 31, 2023
Millions
PSAs	$6.0	$6.0
Customer Deposits	5.7	7.4
Provision for Interim Rate Refund	5.5	—
Operating Lease Liabilities	3.1	3.0
Finance Lease Liabilities	0.4	0.4
Other	59.5	75.1
Total Other Current Liabilities	$80.2	$91.9

Other Non-Current Liabilities	March 31, 2024	December 31, 2023
Millions
Asset Retirement Obligation (a)	$206.1	$202.9
PSAs	19.5	20.9
Operating Lease Liabilities	8.3	7.7
Finance Lease Liabilities	1.5	1.6
Other	32.6	31.2
Total Other Non-Current Liabilities	$268.0	$264.3

(a)The asset retirement obligation is primarily related to our Regulated Operations and is funded through customer rates over the life of the related assets. Additionally, BNI Energy funds its obligation through its cost-plus coal supply agreements for which BNI Energy has recorded a receivable of $37.2 million in Other Non-Current Assets on the Consolidated Balance Sheet as of March 31, 2024 ($37.2 million as of December 31, 2023).

NOTE 1. OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES (Continued)

	Three Months Ended
	March 31,
Other Income	2024	2023
Millions
Pension and Other Postretirement Benefit Plan Non-Service Credits (a)	$4.3	$2.0
Interest and Investment Income	1.9	1.1
AFUDC - Equity	1.2	0.5
Other	1.2	0.5
Total Other Income	$8.6	$4.1

(a)These are components of net periodic pension and other postretirement benefit cost other than service cost. (See Note 9. Pension and Other Postretirement Benefit Plans.)

	Three Months Ended
	March 31,
Supplemental Statement of Cash Flows Information	2024	2023
Millions
Cash Paid for Interest – Net of Amounts Capitalized	$25.7	$24.6
Noncash Investing and Financing Activities
Decrease in Accounts Payable for Capital Additions to Property, Plant and Equipment	$(5.9)	$(7.1)
Capitalized Asset Retirement Costs	$2.2	$2.4
AFUDC–Equity	$1.2	$0.5

New Accounting Pronouncements and Disclosure Rules.

SEC Climate-related Disclosures Rule. On March 6, 2024, the SEC issued the final rules regarding the enhancement and standardization of climate-related disclosures for investors (Rule). The Rule requires registrants to provide certain climate-related information in their annual reports and registration statements. These requirements include disclosing climate-related risks that materially affect or are reasonably likely to materially affect a registrant’s business strategy, results of operations, or financial condition as well as certain disclosures related to greenhouse-gas emissions, and the effects of severe weather events and other natural conditions. The disclosure requirements will begin phasing in for annual periods beginning in 2025. The Company is evaluating the final rule to determine its impact on the Company’s disclosures. The Rule is currently being challenged before the U.S. Court of Appeals, and the SEC issued a voluntary stay of the Rule on April 4, 2024, pending judicial review.

There are no other new accounting pronouncements or rules that we anticipate having a material effect on the presentation of ALLETE’s consolidated financial statements.

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Regulatory Matters

3 Months Ended

Mar. 31, 2024

Regulated Operations [Abstract]

Regulatory Matters

REGULATORY MATTERS

Regulatory matters are summarized in Note 4. Regulatory Matters to the Consolidated Financial Statements in our 2023 Form 10-K, with additional disclosure provided in the following paragraphs.

Electric Rates. Entities within our Regulated Operations segment file for periodic rate revisions with the MPUC, PSCW or FERC. As authorized by the MPUC, Minnesota Power also recognizes revenue under cost recovery riders for transmission, renewable, and environmental investments and expenditures. Revenue from cost recovery riders was $8.3 million for the three months ended March 31, 2024 ($16.4 million for the three months ended March 31, 2023).

NOTE 2. REGULATORY MATTERS (Continued)

2024 Minnesota General Rate Case. On November 1, 2023, Minnesota Power filed a retail rate increase request with the MPUC seeking an average increase of approximately 12.00 percent for retail customers, net of rider revenue incorporated into base rates. The rate filing seeks a return on equity of 10.30 percent and a 53.00 percent equity ratio. On an annualized basis, the requested final rate increase would generate approximately $89 million in additional revenue. In separate orders dated December 19, 2023, the MPUC accepted the filing as complete and approved an annual interim rate increase of approximately $64 million, net of rider revenue, beginning January 1, 2024, subject to refund.

On May 3, 2024, Minnesota Power entered into a settlement agreement with the Minnesota Department of Commerce, Minnesota Office of the Attorney General, Residential Utilities Division, and Large Power Intervenors to settle the retail rate increase request. The settlement agreement is subject to approval by the MPUC. As part of the settlement agreement, the parties have agreed on all issues, including an overall rate increase of $33.97 million, net of rider revenue and amounts transferring to the fuel adjustment clause, a return on equity of 9.78 percent, all non-financial items and cost allocation. As a result of the settlement, Minnesota Power recorded a reserve for an interim rate refund of $5.5 million pre-tax as of March 31, 2024, which is subject to MPUC approval of the settlement agreement and Minnesota Power’s refund calculation.

2022 Minnesota General Rate Case. Minnesota Power is appealing with the Minnesota Court of Appeals (Court) specific aspects of the MPUC’s February 2023 and May 2023 rate case orders for the ratemaking treatment of Taconite Harbor and Minnesota Power’s prepaid pension asset. Oral arguments on the appeal are expected to be heard by the Court in the second quarter of 2024 with a decision expected in the third quarter of 2024. We are unable to predict the outcome of this proceeding.

2024 Wisconsin General Rate Case. On March 29, 2024, SWL&P filed a rate increase request for its electric, gas and water utilities with the PSCW. The filing seeks an overall return on equity of 10.00 percent and a 55.00 percent equity ratio. On an annualized basis, the requested change would increase rates by approximately 5.90 percent for retail customers and generate an estimated $7.3 million of additional revenue. The change to SWL&P customers’ rates will be determined by the PSCW later this year. Any rate adjustments are anticipated to become effective in January 2025.

Transmission Cost Recovery Rider. Minnesota Power has an approved cost recovery rider in place to charge retail customers on a current basis for certain transmission investments and expenditures, including a return on the capital invested. Current customer billing rates are based on an MPUC order dated December 19, 2023, which provisionally approved Minnesota Power’s latest transmission factor filing submitted on October 24, 2023. Updated billing rates were included on customer bills starting in the first quarter of 2024, and the MPUC approved Minnesota Power’s transmission factor filing with no changes in an order dated March 5, 2024.

Renewable Cost Recovery Rider. Minnesota Power has an approved cost recovery rider in place to charge retail customers on a current basis for the costs of certain renewable investments and expenditures, including a return on the capital invested. Current customer billing rates for the renewable cost recovery rider were approved by the MPUC in an order dated October 3, 2023. On March 27, 2024, Minnesota Power submitted its latest renewable factor filing. If the filing is approved, Minnesota Power would be authorized to include updated billing rates on customer bills beginning October 1, 2024.

Solar Cost Recovery Rider. Minnesota Power has an approved cost recovery rider in place to charge retail customers on a current basis for solar costs related to investments and expenditures for meeting the state of Minnesota’s solar energy standard. Current customer billing rates were approved by the MPUC in an order dated December 26, 2023. Updated billing rates were included on customer bills starting in the first quarter of 2024.

Fuel Adjustment Clause. Minnesota Power incurred lower fuel and purchased power costs in 2023 than those factored in its fuel adjustment forecast filed in May 2022 for 2023, which resulted in the recognition of an approximately $13 million regulatory liability as of March 31, 2024, and December 31, 2023. Minnesota Power requested to refund the regulatory liability beginning in the third quarter of 2024 as part of its annual true-up filing submitted to the MPUC on March 1, 2024.

NOTE 2. REGULATORY MATTERS (Continued)

Energy Conservation and Optimization (ECO) Plan. On April 1, 2024, Minnesota Power submitted its 2023 ECO annual filing (formerly the Conservation Improvement Plan) detailing Minnesota Power’s ECO plan results and requesting a financial incentive of $2.2 million, which will be recognized upon approval by the MPUC. In 2023, a financial incentive of $2.2 million was recognized in the third quarter upon approval by the MPUC of the 2022 ECO annual filing. The financial incentives are recognized in the period in which the MPUC approves the filing.

Regulatory Assets and Liabilities. Our regulated utility operations are subject to accounting standards for the effects of certain types of regulation. Regulatory assets represent incurred costs that have been deferred as they are probable for recovery in customer rates. Regulatory liabilities represent obligations to make refunds to customers and amounts collected in rates for which the related costs have not yet been incurred. The Company assesses quarterly whether regulatory assets and liabilities meet the criteria for probability of future recovery or deferral. The recovery, refund or credit to rates for these regulatory assets and liabilities will occur over the periods either specified by the applicable regulatory authority or over the corresponding period related to the asset or liability.

Regulatory Assets and Liabilities	March 31, 2024	December 31, 2023
Millions
Current Regulatory Assets (a)
Fuel Adjustment Clause	$8.1	$8.7
Other	0.6	0.6
Total Current Regulatory Assets	$8.7	$9.3
Non-Current Regulatory Assets
Defined Benefit Pension and Other Postretirement Plans	$217.3	$218.6
Income Taxes	85.1	88.1
Asset Retirement Obligations	38.3	37.7
Cost Recovery Riders	27.6	33.8
Taconite Harbor	18.3	20.9
Manufactured Gas Plant	13.1	13.2
PPACA Income Tax Deferral	3.9	3.9
Fuel Adjustment Clause	2.1	5.0
Other	3.3	4.2
Total Non-Current Regulatory Assets	$409.0	$425.4
Current Regulatory Liabilities (b)
Fuel Adjustment Clause	$9.0	—
Provision for Interim Rate Refund	5.5	—
Transmission Formula Rates Refund	1.0	$1.5
Other	1.6	2.4
Total Current Regulatory Liabilities	$17.1	$3.9
Non-Current Regulatory Liabilities
Income Taxes	$302.3	$310.0
Wholesale and Retail Contra AFUDC	77.3	78.0
Plant Removal Obligations	69.3	67.0
Defined Benefit Pension and Other Postretirement Benefit Plans	45.5	48.6
Non-Jurisdictional Land Sales	35.1	30.2
Investment Tax Credits	13.5	13.6
Fuel Adjustment Clause	8.2	15.5
Boswell Units 1 and 2 Net Plant and Equipment	6.7	6.7
Other	6.1	4.4
Total Non-Current Regulatory Liabilities	$564.0	$574.0

(a)Current regulatory assets are presented within Prepayments and Other on the Consolidated Balance Sheet.

(b)Current regulatory liabilities are presented within Other Current Liabilities on the Consolidated Balance Sheet.

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Equity Investments

3 Months Ended

Mar. 31, 2024

Equity Method Investments and Joint Ventures [Abstract]

Equity Investments

EQUITY INVESTMENTS

Investment in ATC. Our wholly-owned subsidiary, ALLETE Transmission Holdings, owns approximately 8 percent of ATC, a Wisconsin-based utility that owns and maintains electric transmission assets in portions of Wisconsin, Michigan, Minnesota and Illinois. We account for our investment in ATC under the equity method of accounting.

ALLETE’s Investment in ATC
Millions
Equity Investment Balance as of December 31, 2023	$179.7
Cash Investments	1.6
Equity in ATC Earnings	5.7
Distributed ATC Earnings	(4.6)
Amortization of the Remeasurement of Deferred Income Taxes	0.3
Equity Investment Balance as of March 31, 2024	$182.7

ATC’s authorized return on equity was 10.02 percent, or 10.52 percent including an incentive adder for participation in a regional transmission organization, based on a 2020 FERC order which is subject to various outstanding legal challenges related to the return on equity calculation and refund period ordered by the FERC. In August 2022, the U.S. Court of Appeals for the District of Columbia Circuit vacated and remanded the 2020 FERC order back to FERC. We cannot predict the return on equity the FERC will ultimately authorize in the remanded proceeding.

In addition, the FERC issued a Notice of Proposed Rulemaking in 2021 proposing to limit the 0.50 percent incentive adder for participation in a regional transmission organization to only the first three years of membership in such an organization. If this proposal is adopted, our equity in earnings from ATC would be reduced by approximately $1 million pre-tax annually.

Investment in Nobles 2. Our subsidiary, ALLETE South Wind, owns 49 percent of Nobles 2, the entity that owns and operates a 250 MW wind energy facility in southwestern Minnesota pursuant to a 20-year PPA with Minnesota Power. We account for our investment in Nobles 2 under the equity method of accounting.

ALLETE’s Investment in Nobles 2
Millions
Equity Investment Balance as of December 31, 2023	$151.5
Equity in Nobles 2 Earnings (a)	(0.2)
Distributed Nobles 2 Earnings	(0.9)
Equity Investment Balance as of March 31, 2024	$150.4

(a)The Company also recorded earnings from net loss attributable to non-controlling interest of $3.0 million related to its investment in Nobles 2.

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Fair Value

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Fair Value

FAIR VALUE

Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We utilize market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs can be readily observable, market corroborated or generally unobservable. We primarily apply the market approach for recurring fair value measurements and endeavor to utilize the best available information. Accordingly, we utilize valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. These inputs, which are used to measure fair value, are prioritized through the fair value hierarchy. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). Descriptions of the three levels of the fair value hierarchy are discussed in Note 7. Fair Value to the Consolidated Financial Statements in our 2023 Form 10-K.

NOTE 4. FAIR VALUE (Continued)

The following tables set forth, by level within the fair value hierarchy, our assets and liabilities that were accounted for at fair value on a recurring basis as of March 31, 2024, and December 31, 2023. Each asset and liability is classified based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, which may affect the valuation of these assets and liabilities and their placement within the fair value hierarchy levels. The estimated fair value of Cash and Cash Equivalents on the Consolidated Balance Sheet approximates the carrying amount and therefore is excluded from the recurring fair value measures in the following tables.

	Fair Value as of March 31, 2024
Recurring Fair Value Measures	Level 1	Level 2	Level 3	Total
Millions
Assets
Investments (a)
Available-for-sale – Equity Securities	$8.6	—	—	$8.6
Available-for-sale – Corporate and Governmental Debt Securities (b)	—	$6.5	—	6.5
Cash Equivalents	6.0	—	—	6.0
Total Fair Value of Assets	$14.6	$6.5	—	$21.1
Liabilities
Deferred Compensation (c)	—	$18.1	—	$18.1
Total Fair Value of Liabilities	—	$18.1	—	$18.1
	Fair Value as of December 31, 2023
Recurring Fair Value Measures	Level 1	Level 2	Level 3	Total
Millions
Assets
Investments (a)
Available-for-sale – Equity Securities	$8.7	—	—	$8.7
Available-for-sale – Corporate and Governmental Debt Securities	—	$6.0	—	6.0
Cash Equivalents	5.8	—	—	5.8
Total Fair Value of Assets	$14.5	$6.0	—	$20.5
Liabilities
Deferred Compensation (c)	—	$16.5	—	$16.5
Total Fair Value of Liabilities	—	$16.5	—	$16.5

(a)Included in Other Non-Current Assets on the Consolidated Balance Sheet.

(b)As of March 31, 2024, the aggregate amount of available-for-sale corporate and governmental debt securities maturing in one year or less was $1.7 million, in one year to less than three years was $2.7 million, in three years to less than five years was $1.6 million and in five or more years was $0.5 million.

(c)Included in Other Non-Current Liabilities on the Consolidated Balance Sheet.

Fair Value of Financial Instruments. With the exception of the item listed in the following table, the estimated fair value of all financial instruments approximates the carrying amount. The fair value of the item listed in the following table was based on quoted market prices for the same or similar instruments (Level 2).

Financial Instruments	Carrying Amount	Fair Value
Millions
Short-Term and Long-Term Debt (a)
March 31, 2024	$1,797.3	$1,646.8
December 31, 2023	$1,799.4	$1,670.6

(a)Excludes unamortized debt issuance costs.

NOTE 4. FAIR VALUE (Continued)

Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis. Non-financial assets such as equity method investments, land inventory, and property, plant and equipment are measured at fair value when there is an indicator of impairment and recorded at fair value only when an impairment is recognized. For the three months ended March 31, 2024, and the year ended December 31, 2023, there were no indicators of impairment for these non-financial assets.

We continue to monitor changes in the broader energy markets along with wind resource expectations that could indicate impairment at ALLETE Clean Energy wind energy facilities upon contract expirations or for facilities without long-term contracts for their entire output. A continued decline or volatility in energy prices or lower wind resource expectations could result in a future impairment.

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Short-Term and Long-Term Debt

3 Months Ended

Mar. 31, 2024

Debt Disclosure [Abstract]

Short-Term and Long-Term Debt

SHORT-TERM AND LONG-TERM DEBT

The following tables present the Company’s short-term and long-term debt as of March 31, 2024, and December 31, 2023:

March 31, 2024	Principal	Unamortized Debt Issuance Costs	Total
Millions
Short-Term Debt	$17.2	—	$17.2
Long-Term Debt	1,780.1	$(7.7)	1,772.4
Total Debt	$1,797.3	$(7.7)	$1,789.6

December 31, 2023	Principal	Unamortized Debt Issuance Costs	Total
Millions
Short-Term Debt	$111.5	$(0.1)	$111.4
Long-Term Debt	1,687.9	(8.0)	1,679.9
Total Debt	$1,799.4	$(8.1)	$1,791.3

We had $19.4 million outstanding in standby letters of credit and $94.0 million outstanding draws under our lines of credit as of March 31, 2024 ($19.4 million in standby letters of credit and $34.1 million outstanding draws as of December 31, 2023). We also have standby letters of credit outstanding under other letter of credit facilities. (See Note 6. Commitments, Guarantees and Contingencies.)

On April 23, 2024, ALLETE issued $100 million of its First Mortgage Bonds (Bonds) to certain institutional buyers in the private placement market. The Bonds, which bear interest at 5.72 percent, will mature in April 2039 and pay interest semi-annually in April and October of each year, commencing on October 30, 2024. ALLETE has the option to prepay all or a portion of the Bonds at its discretion, subject to a make-whole provision. The Bonds are subject to additional terms and conditions which are customary for these types of transactions. Proceeds from the sale of the Bonds were used to refinance existing indebtedness and for general corporate purposes. The Bonds were sold in reliance on an exemption from registration under Section 4(a)(2) of the Securities Act of 1933, as amended, to institutional accredited investors.

Financial Covenants. Our long-term debt arrangements contain customary covenants. In addition, our lines of credit and letters of credit supporting certain long-term debt arrangements contain financial covenants. Our compliance with financial covenants is not dependent on debt ratings. The most restrictive financial covenant requires ALLETE to maintain a ratio of indebtedness to total capitalization (as the amounts are calculated in accordance with the respective long-term debt arrangements) of less than or equal to 0.65 to 1.00, measured quarterly. As of March 31, 2024, our ratio was approximately 0.36 to 1.00. Failure to meet this covenant would give rise to an event of default if not cured after notice from the lender, in which event ALLETE may need to pursue alternative sources of funding. Some of ALLETE’s debt arrangements contain “cross-default” provisions that would result in an event of default if there is a failure under other financing arrangements to meet payment terms or to observe other covenants that would result in an acceleration of payments due. ALLETE has no significant restrictions on its ability to pay dividends from retained earnings or net income. As of March 31, 2024, ALLETE was in compliance with its financial covenants.

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Commitments, Guarantees and Contingencies

3 Months Ended

Mar. 31, 2024

Commitments and Contingencies Disclosure [Abstract]

Commitments, Guarantees and Contingencies

COMMITMENTS, GUARANTEES AND CONTINGENCIES

Power Purchase and Sale Agreements. Our long-term PPAs have been evaluated under the accounting guidance for variable interest entities. We have determined that either we have no variable interest in the PPAs or, where we do have variable interests, we are not the primary beneficiary; therefore, consolidation is not required. These conclusions are based on the fact that we do not have both control over activities that are most significant to the entity and an obligation to absorb losses or receive benefits from the entity’s performance. Our financial exposure relating to these PPAs is limited to our capacity and energy payments.

Our PPAs are summarized in Note 9. Commitments, Guarantees and Contingencies to the Consolidated Financial Statements in our 2023 Form 10-K, with additional disclosure provided in the following paragraphs.

Square Butte PPA. As of March 31, 2024, Square Butte had total debt outstanding of $162.6 million. Fuel expenses are recoverable through Minnesota Power’s fuel adjustment clause and include the cost of coal purchased from BNI Energy under a long-term contract. Minnesota Power’s cost of power purchased from Square Butte during the three months ended March 31, 2024, was $22.9 million ($22.1 million for the same period in 2023). This reflects Minnesota Power’s pro rata share of total Square Butte costs based on the 50 percent output entitlement. Included in this amount was Minnesota Power’s pro rata share of interest expense of $1.3 million ($1.3 million for the same period in 2023). Minnesota Power’s payments to Square Butte are approved as a purchased power expense for ratemaking purposes by both the MPUC and the FERC.

Minnkota Power PSA. Minnesota Power has a PSA with Minnkota Power, which commenced in 2014. Under the PSA, Minnesota Power is selling a portion of its entitlement from Square Butte to Minnkota Power, resulting in Minnkota Power’s net entitlement increasing and Minnesota Power’s net entitlement decreasing until Minnesota Power’s share is eliminated at the end of 2025. Of Minnesota Power’s 50 percent output entitlement, Minnesota Power sold to Minnkota Power approximately 41 percent in 2024 and 37 percent in 2023.

Coal, Rail and Shipping Contracts. Minnesota Power has coal supply agreements providing for the purchase of a significant portion of its coal requirements through December 2025. Minnesota Power also has coal transportation agreements in place for the delivery of a significant portion of its coal requirements through December 2024. The costs of fuel and related transportation costs for Minnesota Power’s generation are recoverable from Minnesota Power’s utility customers through the fuel adjustment clause.

Environmental Matters.

Our businesses are subject to regulation of environmental matters by various federal, state, and local authorities. A number of regulatory changes to the Clean Air Act, the Clean Water Act and various waste management requirements have been promulgated by both the EPA and state authorities over the past several years. Minnesota Power’s facilities are subject to additional requirements under many of these regulations. Minnesota Power is reshaping its generation portfolio, over time, to reduce its reliance on coal, has installed cost-effective emission control technology, and advocates for sound science and policy during rulemaking implementation.

We consider our businesses to be in substantial compliance with currently applicable environmental regulations and believe all necessary permits have been obtained. We anticipate that with many state and federal environmental regulations and requirements finalized, or to be finalized in the near future, potential expenditures for future environmental matters may be material and require significant capital investments. Minnesota Power has evaluated various environmental compliance scenarios using possible outcomes of environmental regulations to project power supply trends and impacts on customers.

We review environmental matters on a quarterly basis. Accruals for environmental matters are recorded when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated based on current law and existing technologies. Accruals are adjusted as assessment and remediation efforts progress, or as additional technical or legal information becomes available. Accruals for environmental liabilities are included in the Consolidated Balance Sheet at undiscounted amounts and exclude claims for recoveries from insurance or other third parties. Costs related to environmental contamination treatment and cleanup are expensed unless recoverable in rates from customers.

Air. The electric utility industry is regulated both at the federal and state level to address air emissions. Minnesota Power’s thermal generating facilities mainly burn low-sulfur western sub-bituminous coal. All of Minnesota Power’s coal-fired generating facilities are equipped with pollution control equipment such as scrubbers, baghouses and low NOX technologies. Under currently applicable environmental regulations, these facilities are substantially compliant with emission requirements.

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES (Continued)

Environmental Matters (Continued)

Cross-State Air Pollution Rule (CSAPR). The CSAPR requires certain states in the eastern half of the U.S., including Minnesota, to reduce power plant emissions that contribute to ozone or fine particulate pollution in other states. The CSAPR does not require installation of controls but does require facilities have sufficient allowances to cover their emissions on an annual basis. These allowances are allocated to facilities from each state’s annual budget and can be bought and sold. Based on our review of the NOX and SO2 allowances issued and pending issuance as well as consideration of current rules, we currently expect generation levels and emission rates will result in continued compliance with the CSAPR. Minnesota Power will continue to monitor ongoing CSAPR rulemakings and compliance implementation, including the EPA’s Good Neighbor Rule which modifies certain aspects of the CSAPR’s program scope and extent (see EPA Good Neighbor Plan for 2015 Ozone NAAQS).

National Ambient Air Quality Standards (NAAQS). The EPA is required to review the NAAQS every five years. If the EPA determines that a state’s air quality is not in compliance with the NAAQS, the state is required to adopt plans describing how it will reduce emissions to attain the NAAQS. Minnesota Power actively monitors NAAQS developments, and the EPA is currently reviewing the primary or secondary NAAQS for NOx, SO2, and ozone. On February 7, 2024, the EPA announced a final rule lowering the annual primary standard for fine particulate matter while retaining other existing primary and secondary standards such as those for coarse particulate matter. The Company is reviewing the new standard to determine potential impacts. Anticipated timelines and compliance costs related to this new standard and other potential NAAQS revisions cannot yet be estimated; however, costs could be material. Minnesota Power would seek recovery of additional costs through a rate proceeding.

EPA Good Neighbor Plan for 2015 Ozone NAAQS. On June 5, 2023, after disapproving state implementation plans, the EPA published a final Federal Implementation Plan (FIP) rule in the Federal Register, the Good Neighbor Plan, to address regional ozone transport for the 2015 Ozone NAAQS by reducing NOx emissions during the period of May 1 through September 30 (ozone season). In its justification for the final rule, the EPA asserted that 23 states, including Minnesota, were modeled as significant contributors to downwind states’ challenges in attaining or maintaining ozone NAAQS compliance within their state borders. The Good Neighbor Plan is designed to resolve this interstate transport issue by implementing a variety of NOx reduction strategies, including federal implementation plan requirements, NOx emission limitations, and ozone season allowance program requirements. The final rule imposed restrictions on fossil-fuel fired power plants in 22 states and on certain industrial sources in 20 states, with implementation occurring through changes to the existing CSAPR program for power plants.

Since the EPA partially disapproved the Good Neighbor State Implementation Plans (SIPs) for the states of Minnesota and Wisconsin, among others, Minnesota is subject to the final Good Neighbor Plan. However, Minnesota Power and a coalition of other Minnesota utilities and industry (the parties) co-filed challenges to the EPA’s final Minnesota SIP disapproval, submitting a petition for reconsideration and stay to the EPA, and a petition for judicial review to the U.S. Court of Appeals for the Eighth Circuit (Eighth Circuit Court). The parties are challenging and requesting reconsideration of certain technical components of the EPA’s review and subsequent partial disapproval of the state of Minnesota’s SIP. On July 5, 2023, the Eighth Circuit Court granted a stay of the SIP disapproval preventing the Good Neighbor Plan from taking effect in Minnesota. On March 28, 2024, the EPA issued a partial denial of several administrative reconsideration and stay petitions, including from the Minnesota coalition.

On September 29, 2023, the EPA issued an updated final interim rule addressing the stays in Minnesota and five other states, formally delaying the effective date of the final FIP for states with active stays in place. The state of Minnesota was therefore not subject to compliance obligations for the 2023 ozone season. Future compliance obligations will depend on resolution of the stay. Additionally, challenges have been filed against the final FIP rule by the Minnesota coalition parties and other entities, although the Minnesota coalition FIP challenge is currently in abeyance pending resolution of the SIP disapproval case. On February 21, 2024, the U.S. Supreme Court heard arguments from several states and industry groups requesting a national stay of the FIP rule. Anticipated compliance costs related to final Good Neighbor Plan compliance cannot yet be estimated due to uncertainties about SIP approval resolution, implementation timing, FIP rule outcome, and allowance costs and facility emissions during the ozone season. However, the costs could be material, including costs of additional NOx controls, emission allowance program participation, or operational changes, if any are required. Minnesota Power would seek recovery of additional costs through a rate proceeding.

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES (Continued)

Environmental Matters (Continued)

EPA National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial and Institutional Boilers and Process Heaters (Industrial Boiler MACT) Rule. A final rule issued by the EPA for Industrial Boiler MACT became effective in 2013 with compliance required at major existing sources in 2016, which applied to Minnesota Power’s Hibbard Renewable Energy Center and Rapids Energy Center. Compliance consisted largely of adjustments to fuels and operating practices and compliance costs were not material. After this initial rulemaking, litigation from 2016 through 2018 resulted in court orders directing that the EPA reconsider certain aspects of the regulation. A final rule incorporating these revisions became effective in December 2022, with a compliance deadline of October 6, 2025. Compliance costs are not expected to be material.

EPA Mercury and Air Toxics Standards (MATS) Rule. On April 25, 2024, the EPA published a final rule to revise the existing 2012 MATS Rule, which regulates air emissions of hazardous air pollutants from coal- and oil-fired electric generating units (EGUs). The final rule eliminates certain MATS compliance flexibility, lowers the particulate emission standard for all coal-fired EGUs, and reduces the mercury emission standard for lignite-fired EGUs. The rule will become effective 60 days after publication in the Federal Register, with compliance beginning in 2027. The MATS regulation applies at Minnesota Power’s Boswell facility, which is currently well-controlled for these emissions and already complying with some of the new requirements. The Company is analyzing the new rule but anticipates that its impacts to Boswell may be minimal. However, compliance costs cannot yet be estimated, and recovery of any additional costs would be sought through a rate proceeding.

Climate Change. The scientific community generally accepts that emissions of GHGs are linked to global climate change which creates physical and financial risks. Physical risks could include but are not limited to: increased or decreased precipitation and water levels in lakes and rivers; increased or other changes in temperatures; increased risk of wildfires; and changes in the intensity and frequency of extreme weather events. These all have the potential to affect the Company’s business and operations. We are addressing climate change by taking the following steps that also ensure reliable and environmentally compliant generation resources to meet our customers’ requirements:

•Expanding renewable power supply for both our operations and the operations of others;

•Providing energy conservation initiatives for our customers and engaging in other demand side management efforts;

•Improving efficiency of our generating facilities;

•Supporting research of technologies to reduce carbon emissions from generating facilities and carbon sequestration efforts;

•Evaluating and developing less carbon intensive future generating assets such as efficient and flexible natural gas‑fired generating facilities;

•Managing vegetation on right-of-way corridors to reduce potential wildfire or storm damage risks; and

•Practicing sound forestry management in our service territories to create landscapes more resilient to disruption from climate-related changes, including planting and managing long-lived conifer species.

EPA Regulation of GHG Emissions. On April 25, 2024, the EPA issued several final greenhouse gas regulations to establish emissions standards and guidelines for fossil fuel-fired electric generating units (EGUs) under Section 111 of the Clean Air Act (CAA). The final rules revise new source performance standards (NSPS) for new, modified and reconstructed EGUs (Section 111(b) of the CAA) and creates new emission guidelines for existing EGUs (Section 111(d) of the CAA). The action also officially repeals the predecessor regulation “Affordable Clean Energy Rule”, first issued in 2019 and later vacated in 2021. Compliance will be required beginning January 1, 2030 for existing sources, and upon commencing operation of new units. The 111(d) rule also requires states to submit plans to provide for the establishment, implementation and enforcement of standards of performance for existing sources. States must submit their plans to the EPA within 24 months after publication of the final emissions guidelines.

The final 111 rules apply to several Company assets, including existing EGUs at the Boswell and Laskin facilities as well as the proposed combined cycle natural gas-fired generating facility, NTEC. The Company is reviewing the new rule, but anticipates compliance may require operational or planning adjustments. The state implementation plan process for Section 111(d) existing units will also be a factor in determining specific requirements and timing. We are unable to predict compliance costs at this time; however, the costs could be material. Minnesota Power would seek recovery of additional costs through a rate proceeding.

Water. The Clean Water Act requires NPDES permits be obtained from the EPA or delegated state agencies for any wastewater discharged into navigable waters. We have obtained all necessary NPDES permits, including NPDES storm water permits for applicable facilities, to conduct our operations.

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES (Continued)

Environmental Matters (Continued)

Steam Electric Power Generating Effluent Limitations Guidelines. In 2015, the EPA issued revised federal effluent limitation guidelines (ELG) for steam electric power generating stations under the Clean Water Act. It set effluent limits and prescribed Best Available Control Technology (BACT) for several wastewater streams, including flue gas desulphurization (FGD) water, bottom ash transport water and coal combustion landfill leachate. In October 2020, the EPA published a final ELG Rule allowing re-use of bottom ash transport water in FGD scrubber systems with limited discharges related to maintaining system water balance. The rule set technology standards and numerical pollutant limits for discharges of bottom ash transport water and FGD wastewater. Compliance deadlines depend on subcategory, with compliance generally required as soon as possible, beginning after October 13, 2021, but no later than December 31, 2025, or December 31, 2028, in some specific cases.

On April 25, 2024, the EPA released a pre-publication version of a final ELG rule to update the 2020 ELGs. In the final rule, the EPA is revising ELGs for existing sources, including establishing zero discharge limitations for bottom ash transport water, FGD wastewater, and combustion residual leachate, and allowing states to set discharge limits for legacy wastewater in surface impoundments based on best professional judgment. The rule proposes to maintain exemptions for units permanently ceasing coal combustion by 2028, and adds a new subcategory for units that have already complied with either the 2015 or 2020 ELG rules and which will retire by 2032. The final ELG rule also establishes mercury and arsenic limitations for functionally equivalent discharges of leachate via groundwater to surface water. Compliance deadlines are determined by the applicable state permitting authority. Compliance deadlines could be required as soon as 60 days after the final rule is published in the Federal Register, but no later than December 31, 2029.

Bottom ash transport and FGD wastewater ELGs are not expected to have a significant impact on Minnesota Power operations. Zero leachate discharge requirements have the potential to impact dewatering associated with the closed Taconite Harbor dry ash landfill and Laskin’s closed Cell E impoundment. New limitations for arsenic and mercury related to functionally equivalent (groundwater to surface water) discharges are not currently anticipated to impact Minnesota Power facilities.

We estimate no additional material compliance costs for ELG bottom ash water and FGD requirements. Compliance costs we might incur related to other ELG waste streams (e.g., leachate) or other potential future water discharge regulations at Minnesota Power facilities cannot be estimated; however, the costs could be material, including costs associated with wastewater treatment and re-use. Minnesota Power would seek recovery of additional costs through a rate proceeding.

Permitted Water Discharges – Sulfate. In 2017, the MPCA released a draft water quality standard in an attempt to update Minnesota’s existing 10 mg/L sulfate limit for waters used for the production of wild rice with the proposed rulemaking heard before an administrative law judge (ALJ). In 2018, the ALJ rejected significant portions of the proposed rulemaking and the MPCA subsequently withdrew the rulemaking. The existing 10 mg/L limit remains in place, but the MPCA is currently prohibited under state law from listing wild rice waters as impaired or requiring sulfate reduction technology.

The federal Clean Water Act requires the MPCA to update the state's impaired water list every two years. Beginning in 2021 through the latest draft approved by the EPA in April 2024, this list now includes Minnesota lakes and streams identified as wild rice waters that are listed for sulfate impairment. The list could subsequently be used to set sulfate limits in discharge permits for power generation facilities and municipal and industrial customers, including paper and pulp facilities, and mining operations. At this time, we are unable to determine the specific impacts these developments may have on Minnesota Power operations or its customers, if any. Minnesota Power would seek recovery of additional costs through a rate proceeding.

Solid and Hazardous Waste. The Resource Conservation and Recovery Act of 1976 regulates the management and disposal of solid and hazardous wastes. We are required to notify the EPA of hazardous waste activity and, consequently, routinely submit reports to the EPA.

Coal Ash Management Facilities. Minnesota Power produces the majority of its coal ash at Boswell, with small amounts of ash generated at Hibbard Renewable Energy Center. Ash storage and disposal methods include storing ash in clay-lined onsite impoundments (ash ponds), disposing of dry ash in a lined dry ash landfill, applying ash to land as an approved beneficial use, and trucking ash to state permitted landfills.

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES (Continued)

Environmental Matters (Continued)

Coal Combustion Residuals from Electric Utilities (CCR). In 2015, the EPA published a final rule (2015 Rule) regulating CCR as nonhazardous waste under Subtitle D of the Resource Conservation and Recovery Act (RCRA) in the Federal Register. The rule included additional requirements for new landfill and impoundment construction as well as closure activities related to certain existing impoundments. Costs of compliance for Boswell and Laskin are expected to be incurred primarily over the next 12 years and be between approximately $65 million and $120 million. Compliance costs for CCR at Taconite Harbor are not expected to be material. Minnesota Power would seek recovery of additional costs through a rate proceeding.

Minnesota Power continues to work on minimizing compliance costs through evaluation of beneficial re-use and recycling of CCR. In 2018, a U.S. District Court for the District of Columbia decision vacated specific provisions of the CCR rule, which resulted in a change to the status of several existing clay-lined impoundments at Boswell being considered unlined. In September 2020, the EPA finalized the CCR Part A Rule, which required all unlined impoundments to cease disposal and initiate closure. Upon completion of dry ash conversion activities, Boswell ceased disposal in both impoundments in September 2022. Both impoundments are now inactive and have initiated closure.

On April 25, 2024, the EPA finalized the CCR Legacy Impoundment Rule. The final rule expands the scope of units regulated under the CCR rule to include legacy ponds (inactive surface impoundments at inactive facilities) and creates a new category of units called CCR management units, which includes inactive and closed impoundments and landfills as well as other non-containerized accumulations of CCR. The rule requires all regulated generating facilities to evaluate and identify past deposits of CCR materials on their sites and close or re-close existing CCR units to meet current closure standards, as well as install groundwater monitoring systems, conduct groundwater monitoring, and implement groundwater corrective actions as necessary. Additionally, the EPA finalized portions of the proposed CCR Part B Rule, which allows CCR Units to certify closure while conducting groundwater remediation activities. This rule is currently under review; however impacts to previously closed CCR Units at Boswell and Laskin are anticipated. Compliance costs for Minnesota Power facilities cannot be estimated at this time; however, the costs could be material. Minnesota Power would seek recovery of additional costs through a rate proceeding.

Additionally, the EPA released a proposed CCR Part B rulemaking in February 2020 addressing options for beneficial reuse of CCR materials, alternative liner demonstrations and other CCR regulatory revisions. Portions of the Part B rule addressing alternative liner equivalency standards were finalized in November 2020. Finalization of the remaining beneficial reuse requirements are expected in late 2024. The final CCR federal permit rule is expected in the first half of 2026. The final federal permit rule will finalize procedures for implementing a CCR federal permit program.

Other Environmental Matters.

Manufactured Gas Plant Site. We are reviewing and addressing environmental conditions at a former manufactured gas plant site located in Superior, Wisconsin, and formerly operated by SWL&P. SWL&P has been working with the Wisconsin Department of Natural Resources (WDNR) in determining the extent and location of contamination at the site and surrounding properties. As of March 31, 2024, SWL&P has recorded a liability of approximately $1 million for remediation costs at this site. SWL&P has recorded the recovery of the remediation costs associated with the site as a regulatory asset as we expect recovery of these costs to be allowed by the PSCW.

Other Matters.

Letters of Credit, Surety Bonds and Other Indemnifications.

We have multiple credit facility agreements in place that provide the ability to issue standby letters of credit to satisfy contractual security requirements across our businesses. As of March 31, 2024, we had $150.1 million of outstanding letters of credit issued, including those issued under our revolving credit facility. We do not believe it is likely that any of these outstanding letters of credit will be drawn upon.

In April 2024, under the tax credit transferability provision of the Inflation Reduction Act, we entered into an agreement with a third party to sell a portion of our production tax credits. ALLETE has indemnified the third party for the value of production tax credits sold to date of approximately $14 million.

Regulated Operations. As of March 31, 2024, we had $25.4 million outstanding in standby letters of credit at our Regulated Operations which are pledged as security to MISO, the NDPSC and state agencies.

NOTE 6. COMMITMENTS, GUARANTEES AND CONTINGENCIES (Continued)

Other Matters (Continued)

ALLETE Clean Energy. ALLETE Clean Energy is party to PSAs that expire in various years between 2024 and 2039. As of March 31, 2024, ALLETE Clean Energy has $80.6 million outstanding in standby letters of credit, the majority of which are pledged as security under these PSAs.

Corporate and Other.

BNI Energy. As of March 31, 2024, BNI Energy had surety bonds outstanding of $82.4 million related to the reclamation liability for closing costs associated with its mine and mine facilities. Although its coal supply agreements obligate the customers to provide for the closing costs, additional assurance is required by federal and state regulations. BNI Energy’s total reclamation liability is currently estimated at $82.1 million. BNI Energy does not believe it is likely that any of these outstanding surety bonds will be drawn upon.

Investment in Nobles 2. The Nobles 2 wind energy facility requires standby letters of credit as security for certain contractual obligations. As of March 31, 2024, ALLETE South Wind has $10.1 million outstanding in standby letters of credit, related to its portion of the security requirements relative to its ownership in Nobles 2.

South Shore Energy. As of March 31, 2024, South Shore Energy had $29.7 million outstanding in standby letters of credit pledged as security in connection with the development of NTEC.

Legal Proceedings.

We are involved in litigation arising in the normal course of business. Also in the normal course of business, we are involved in tax, regulatory and other governmental audits, inspections, investigations and other proceedings that involve state and federal taxes, safety, and compliance with regulations, rate base and cost of service issues, among other things. We do not expect the outcome of these matters to have a material effect on our financial position, results of operations or cash flows.

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Earnings Per Share and Common Stock

3 Months Ended

Mar. 31, 2024

Earnings Per Share [Abstract]

Earnings Per Share and Common Stock

EARNINGS PER SHARE AND COMMON STOCK

We compute basic earnings per share using the weighted average number of shares of common stock outstanding during each period. The difference between basic and diluted earnings per share, if any, arises from non-vested restricted stock units and performance share awards granted under our Executive Long-Term Incentive Compensation Plan.

Three Months Ended March 31,		2024			2023
Reconciliation of Basic and Diluted		Dilutive			Dilutive
Earnings Per Share	Basic	Securities	Diluted	Basic	Securities	Diluted
Millions Except Per Share Amounts
Net Income Attributable to ALLETE	$50.7		$50.7	$58.2		$58.2
Average Common Shares	57.6	0.1	57.7	57.3	—	57.3
Earnings Per Share	$0.88		$0.88	$1.02		$1.02

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Income Tax Expense

3 Months Ended

Mar. 31, 2024

Income Tax Disclosure [Abstract]

Income Tax Expense

INCOME TAX EXPENSE

	Three Months Ended
	March 31,
	2024	2023
Millions
Current Income Tax Expense
Federal (a)	$3.5	$5.6
State	3.4	2.2
Total Current Income Tax Expense	$6.9	$7.8
Deferred Income Tax Expense (Benefit)
Federal (b)	$(5.0)	$(8.3)
State	2.4	2.1
Investment Tax Credit Amortization	(0.3)	(0.1)
Total Deferred Income Tax Benefit	$(2.9)	$(6.3)
Total Income Tax Expense	$4.0	$1.5

(a)For the three months ended March 31, 2024 and 2023, the federal current tax expense was partially offset by production tax credits.

(b)For the three months ended March 31, 2024 and 2023, the federal income tax benefit is primarily due to production tax credits.

The Company's tax provision for interim periods is determined using an estimate of its annual effective tax rate, adjusted for discrete items arising in that quarter. In each quarter, the Company updates its estimate of the annual effective tax rate and if the estimated annual effective tax rate changes, the Company would make a cumulative adjustment in that quarter.

	Three Months Ended
Reconciliation of Taxes from Federal Statutory	March 31,
Rate to Total Income Tax Expense	2024		2023
Millions
Income Before Income Taxes	$41.0		$39.1
Statutory Federal Income Tax Rate	21	%	21	%
Income Taxes Computed at Statutory Federal Rate	$8.6		$8.2
Increase (Decrease) in Income Tax Due to:
State Income Taxes – Net of Federal Income Tax Benefit	4.6		3.4
Production Tax Credits (a)	(11.6)		(10.4)
Investment Tax Credits (a)	(0.3)		(2.2)
Regulatory Differences – Excess Deferred Tax	(3.5)		(2.8)
Non-Controlling Interest in Subsidiaries	2.8		3.8
AFUDC – Equity	(0.6)		(0.3)
Other	4.0		1.8
Total Income Tax Expense	$4.0		$1.5

(a)For the three months ended March 31, 2024 and 2023, the credits are presented net of any estimated discount on the sale of certain credits.

For the three months ended March 31, 2024, the effective tax rate was 9.7 percent (3.8 percent for the three months ended March 31, 2023). The effective tax rates for 2024 and 2023 were primarily impacted by production tax credits.

Uncertain Tax Positions. As of March 31, 2024, we had gross unrecognized tax benefits of $1.1 million ($1.1 million as of December 31, 2023). Of the total gross unrecognized tax benefits, $0.6 million represents the amount of unrecognized tax benefits included on the Consolidated Balance Sheet that, if recognized, would favorably impact the effective income tax rate. The unrecognized tax benefit amounts have been presented as an increase to the net deferred tax liability on the Consolidated Balance Sheet.

ALLETE and its subsidiaries file a consolidated federal income tax return as well as combined and separate state income tax returns in various jurisdictions. ALLETE is currently under examination by the state of Minnesota for the tax years 2020 through 2022. ALLETE has no open federal audits and is no longer subject to federal examination for years before 2021 or state examination for years before 2020. Additionally, the statute of limitations related to the federal tax credit carryforwards will remain open until those credits are utilized in subsequent returns.

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Pension and Other Postretirement Benefit Plans

3 Months Ended

Mar. 31, 2024

Retirement Benefits [Abstract]

Pension and Other Postretirement Benefit Plans

PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS

Components of Net Periodic Benefit Cost (Credit)	Pension		Other Postretirement
Three Months Ended March 31,	2024	2023	2024	2023
Millions
Service Cost	$1.6	$1.6	$0.4	$0.6
Non-Service Cost Components (a)
Interest Cost	9.7	10.1	1.0	1.5
Expected Return on Plan Assets	(11.2)	(10.9)	(2.8)	(2.8)
Amortization of Prior Service Credits	—	—	(2.9)	(1.8)
Amortization of Net Loss	1.6	1.4	(0.8)	(0.5)
Net Periodic Benefit Cost (Credit)	$1.7	$2.2	$(5.1)	$(3.0)

(a)These components of net periodic benefit cost (credit) are included in the line item “Other” under Other Income (Expense) on the Consolidated Statement of Income.

Employer Contributions. For the three months ended March 31, 2024, we contributed $25.0 million in cash to the defined benefit pension plans ($6.5 million for the three months ended March 31, 2023); we do not expect to make additional contributions to our defined benefit pension plans in 2024. For the three months ended March 31, 2024 and 2023, we made no contributions to our other postretirement benefit plans; we do not expect to make any contributions to our other postretirement benefit plans in 2024.

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Business Segments

3 Months Ended

Mar. 31, 2024

Segment Reporting [Abstract]

Business Segments

BUSINESS SEGMENTS

We present two reportable segments: Regulated Operations and ALLETE Clean Energy. We measure performance of our operations through budgeting and monitoring of contributions to consolidated net income by each business segment.

Regulated Operations includes three operating segments which consist of our regulated utilities, Minnesota Power and SWL&P, as well as our investment in ATC. ALLETE Clean Energy is our business focused on developing, acquiring and operating clean and renewable energy projects. We also present Corporate and Other which includes New Energy, a renewable energy development company, BNI Energy, our coal mining operations in North Dakota, ALLETE Properties, our legacy Florida real estate investment, along with our investment in Nobles 2, South Shore Energy, our non-rate regulated, Wisconsin subsidiary developing NTEC, other business development and corporate expenditures, unallocated interest expense, a small amount of non-rate base generation, land holdings in Minnesota, and earnings on cash and investments.

NOTE 10. BUSINESS SEGMENTS (Continued)

	Three Months Ended
	March 31,
	2024	2023
Millions
Operating Revenue
Regulated Operations
Residential	$51.5	$49.4
Commercial	49.7	47.7
Municipal	9.0	8.9
Industrial	159.5	144.9
Other Power Suppliers	40.0	35.9
Other	28.6	25.8
Total Regulated Operations	338.3	312.6
ALLETE Clean Energy
Long-term PSA	17.8	18.4
Sale of Wind Energy Facilities	—	181.8
Other	1.3	1.3
Total ALLETE Clean Energy	19.1	201.5
Corporate and Other
Long-term Contract	25.4	25.5
Sale of Renewable Development Projects	13.9	19.8
Other	6.6	5.5
Total Corporate and Other	45.9	50.8
Total Operating Revenue	$403.3	$564.9
Net Income Attributable to ALLETE
Regulated Operations	$44.2	$40.6
ALLETE Clean Energy	3.8	8.5
Corporate and Other	2.7	9.1
Total Net Income Attributable to ALLETE	$50.7	$58.2

	March 31, 2024	December 31, 2023
Millions
Assets
Regulated Operations	$4,345.1	$4,335.0
ALLETE Clean Energy	1,580.0	1,594.1
Corporate and Other	679.5	727.3
Total Assets	$6,604.6	$6,656.4

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Subsequent Event - Agreement and Plan of Merger

3 Months Ended

Mar. 31, 2024

Subsequent Events [Abstract]

Subsequent Event - Agreement and Plan of Merger

SUBSEQUENT EVENT – AGREEMENT AND PLAN OF MERGER

On May 5, 2024, ALLETE entered into the Merger Agreement. Pursuant to the Merger Agreement, on the terms and subject to the conditions set forth therein, Alloy Merger Sub will merge with and into ALLETE, with ALLETE continuing as the surviving corporation in the Merger and becoming a subsidiary of Alloy Parent.

Subject to the terms and conditions set forth in the Merger Agreement, which has been unanimously approved by the board of directors of ALLETE, at the effective time of the Merger (Effective Time), each share of common stock, without par value, of ALLETE (ALLETE common stock) issued and outstanding immediately prior to the Effective Time (other than shares of ALLETE common stock held by any holder who properly exercises dissenters’ rights under Minnesota law in respect of such shares and any shares of ALLETE common stock held by an affiliate of Alloy Parent) shall be converted into the right to receive $67.00 in cash, without interest (Merger Consideration). The aggregate equity value of the ALLETE common stock acquired by Parent will be approximately $3.9 billion as calculated as of May 5, 2024.

In addition, at the Effective Time, each restricted stock unit with respect to ALLETE common stock subject to time-based vesting that is outstanding immediately prior to the Effective Time (RSU) will be cancelled and converted into a contingent right to receive an amount in cash, without interest, equal to the Merger Consideration, payable (i) in the case of such right converted from unvested RSUs, upon the same vesting conditions as applied to the corresponding RSU or (ii) in the case of such right converted from vested RSUs, as soon as reasonably practicable following the closing date of the Merger (the Closing Date). Each performance share award with respect to ALLETE common stock that is outstanding and unvested immediately prior to the Effective Time will be cancelled and converted into a right to receive, without interest, the Merger Consideration multiplied by the number of shares of ALLETE common stock subject to the award, determined based on attainment of the greater of target and actual performance as of the last business day immediately preceding the Closing Date. A pro rata portion (based on the elapsed portion of the performance period at that time) of the converted performance share awards will be paid out as soon as reasonably practicable following the Closing Date, with the remainder of the award being subject to time-vesting for the remainder of the applicable performance period. Further, purchase rights accumulated during the offering period in effect under the Company’s Employee Stock Purchase Plan (ESPP) immediately prior to closing will be automatically exercised into shares of ALLETE common stock no later than five business days prior to the Closing Date, and the ESPP will be terminated as of immediately prior to the Closing Date.

Consummation of the Merger is subject to various closing conditions, including: (1) approval of the shareholders of the Company; (2) receipt of all required regulatory approvals without the imposition of a Burdensome Condition (as defined in the Merger Agreement); (3) absence of any law or order prohibiting the consummation of the Merger; (4) subject to materiality qualifiers, the accuracy of each party’s representations and warranties; (5) each party’s compliance in all material respects with its obligations and covenants under the Merger Agreement; and (6) the absence of a material adverse effect with respect to the Company. The Merger Agreement contains certain termination rights for ALLETE and Alloy Parent, which were described in a Current Report of Form 8-K filed by ALLETE on May 6, 2024. In the Merger Agreement, among other things, ALLETE has agreed, subject to certain exceptions, to, and to cause each of its subsidiaries to conduct its business in the ordinary course, consistent with past practice, from the date of the Merger Agreement until the Effective Time, and not to take certain actions prior to the closing of the Merger without the prior written consent of Alloy Parent (which consent shall not be unreasonably withheld, conditioned or delayed, except where ALLETE seeks Alloy Parent’s consent to enter into a material new line of business or cease operations of an existing material line of business). The Merger Agreement also provides that the Company may request that Alloy Parent purchase up to a total of $300 million of preferred stock of the Company in the second half of 2025, subject to certain parameters. If Alloy Parent declines to purchase the preferred stock, the Company will have the right to issue Company common stock up to certain limits.

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Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income Attributable to ALLETE	$ 50.7	$ 58.2

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Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

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Operations and Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Subsequent Events

Subsequent Events. The Company performed an evaluation of subsequent events for potential recognition and disclosure through the date of the financial statements issuance.

Cash, Cash Equivalents and Restricted Cash

Cash, Cash Equivalents and Restricted Cash. We consider all investments purchased with original maturities of three months or less to be cash equivalents. As of March 31, 2024, restricted cash amounts included in Prepayments and Other on the Consolidated Balance Sheet include collateral deposits required under an ALLETE Clean Energy loan. The restricted cash amounts included in Other Non-Current Assets represent collateral deposits required under an ALLETE Clean Energy loan agreement as well as PSAs.

Inventories – Net

Inventories – Net. Inventories are stated at the lower of cost or net realizable value. Inventories in our Regulated Operations segment are carried at an average cost or first-in, first-out basis. Inventories in our ALLETE Clean Energy segment and Corporate and Other businesses are carried at an average cost, first-in, first-out or specific identification basis.

Regulatory Assets and Liabilities

Regulatory Assets and Liabilities. Our regulated utility operations are subject to accounting standards for the effects of certain types of regulation. Regulatory assets represent incurred costs that have been deferred as they are probable for recovery in customer rates. Regulatory liabilities represent obligations to make refunds to customers and amounts collected in rates for which the related costs have not yet been incurred. The Company assesses quarterly whether regulatory assets and liabilities meet the criteria for probability of future recovery or deferral. The recovery, refund or credit to rates for these regulatory assets and liabilities will occur over the periods either specified by the applicable regulatory authority or over the corresponding period related to the asset or liability.

Investment in ATC

Investment in ATC. Our wholly-owned subsidiary, ALLETE Transmission Holdings, owns approximately 8 percent of ATC, a Wisconsin-based utility that owns and maintains electric transmission assets in portions of Wisconsin, Michigan, Minnesota and Illinois.

Fair Value

FAIR VALUEFair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We utilize market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs can be readily observable, market corroborated or generally unobservable. We primarily apply the market approach for recurring fair value measurements and endeavor to utilize the best available information. Accordingly, we utilize valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. These inputs, which are used to measure fair value, are prioritized through the fair value hierarchy. Each asset and liability is classified based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, which may affect the valuation of these assets and liabilities and their placement within the fair value hierarchy levels.Non-financial assets such as equity method investments, land inventory, and property, plant and equipment are measured at fair value when there is an indicator of impairment and recorded at fair value only when an impairment is recognized.

Power Purchase and Sale Agreements

Power Purchase and Sale Agreements. Our long-term PPAs have been evaluated under the accounting guidance for variable interest entities. We have determined that either we have no variable interest in the PPAs or, where we do have variable interests, we are not the primary beneficiary; therefore, consolidation is not required. These conclusions are based on the fact that we do not have both control over activities that are most significant to the entity and an obligation to absorb losses or receive benefits from the entity’s performance. Our financial exposure relating to these PPAs is limited to our capacity and energy payments.

Environmental Matters

We review environmental matters on a quarterly basis. Accruals for environmental matters are recorded when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated based on current law and existing technologies. Accruals are adjusted as assessment and remediation efforts progress, or as additional technical or legal information becomes available. Accruals for environmental liabilities are included in the Consolidated Balance Sheet at undiscounted amounts and exclude claims for recoveries from insurance or other third parties. Costs related to environmental contamination treatment and cleanup are expensed unless recoverable in rates from customers.

Earnings Per Share and Common Stock

EARNINGS PER SHARE AND COMMON STOCKWe compute basic earnings per share using the weighted average number of shares of common stock outstanding during each period. The difference between basic and diluted earnings per share, if any, arises from non-vested restricted stock units and performance share awards granted under our Executive Long-Term Incentive Compensation Plan.

Income Tax Expense

The Company's tax provision for interim periods is determined using an estimate of its annual effective tax rate, adjusted for discrete items arising in that quarter. In each quarter, the Company updates its estimate of the annual effective tax rate and if the estimated annual effective tax rate changes, the Company would make a cumulative adjustment in that quarter.

Uncertain Tax Positions

The unrecognized tax benefit amounts have been presented as an increase to the net deferred tax liability on the Consolidated Balance Sheet.

Business Segments

BUSINESS SEGMENTSWe present two reportable segments: Regulated Operations and ALLETE Clean Energy. We measure performance of our operations through budgeting and monitoring of contributions to consolidated net income by each business segment.

New Accounting Pronouncements and Disclosure Rules.

New Accounting Pronouncements and Disclosure Rules.

SEC Climate-related Disclosures Rule. On March 6, 2024, the SEC issued the final rules regarding the enhancement and standardization of climate-related disclosures for investors (Rule). The Rule requires registrants to provide certain climate-related information in their annual reports and registration statements. These requirements include disclosing climate-related risks that materially affect or are reasonably likely to materially affect a registrant’s business strategy, results of operations, or financial condition as well as certain disclosures related to greenhouse-gas emissions, and the effects of severe weather events and other natural conditions. The disclosure requirements will begin phasing in for annual periods beginning in 2025. The Company is evaluating the final rule to determine its impact on the Company’s disclosures. The Rule is currently being challenged before the U.S. Court of Appeals, and the SEC issued a voluntary stay of the Rule on April 4, 2024, pending judicial review.

There are no other new accounting pronouncements or rules that we anticipate having a material effect on the presentation of ALLETE’s consolidated financial statements.

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Operations and Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Cash, Cash Equivalents and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheet that aggregate to the amounts presented in the Consolidated Statement of Cash Flows.

Cash, Cash Equivalents and Restricted Cash	March 31, 2024	December 31, 2023	March 31, 2023	December 31, 2022
Millions
Cash and Cash Equivalents	$32.0	$71.9	$29.9	$36.4
Restricted Cash included in Prepayments and Other	5.9	5.1	7.4	1.5
Restricted Cash included in Other Non-Current Assets	2.4	2.4	2.3	2.3
Cash, Cash Equivalents and Restricted Cash on the Consolidated Statement of Cash Flows	$40.3	$79.4	$39.6	$40.2

Inventories – Net

Inventories in our ALLETE Clean Energy segment and Corporate and Other businesses are carried at an average cost, first-in, first-out or specific identification basis.

Inventories – Net	March 31, 2024	December 31, 2023
Millions
Fuel (a)	$30.2	$27.2
Materials and Supplies	119.0	115.7
Renewable Energy Facilities Under Development (b)	33.5	32.5
Total Inventories – Net	$182.7	$175.4

(a)    Fuel consists primarily of coal inventory at Minnesota Power.

(b)    Renewable Energy Facilities Under Development as of March 31, 2024, consists primarily of project costs related to renewable energy development projects at New Energy.

Other Non-Current Assets

Other Non-Current Assets	March 31, 2024	December 31, 2023
Millions
Other Postretirement Benefit Plans	$104.6	$106.3
Contract Assets (a)	17.9	18.5
Operating Lease Right-of-use Assets	11.3	10.7
ALLETE Properties	10.7	10.8
Restricted Cash	2.4	2.4
Finance Lease Right-of-use Assets	2.0	2.1
Other	115.9	112.1
Total Other Non-Current Assets	$264.8	$262.9

(a)    Contract Assets consist of payments made to customers as an incentive to execute or extend service agreements. The payments are being amortized over the term of the respective agreements as a reduction to revenue.

Other Current Liabilities

Other Current Liabilities	March 31, 2024	December 31, 2023
Millions
PSAs	$6.0	$6.0
Customer Deposits	5.7	7.4
Provision for Interim Rate Refund	5.5	—
Operating Lease Liabilities	3.1	3.0
Finance Lease Liabilities	0.4	0.4
Other	59.5	75.1
Total Other Current Liabilities	$80.2	$91.9

Other Non-Current Liabilities

Other Non-Current Liabilities	March 31, 2024	December 31, 2023
Millions
Asset Retirement Obligation (a)	$206.1	$202.9
PSAs	19.5	20.9
Operating Lease Liabilities	8.3	7.7
Finance Lease Liabilities	1.5	1.6
Other	32.6	31.2
Total Other Non-Current Liabilities	$268.0	$264.3

(a)The asset retirement obligation is primarily related to our Regulated Operations and is funded through customer rates over the life of the related assets. Additionally, BNI Energy funds its obligation through its cost-plus coal supply agreements for which BNI Energy has recorded a receivable of $37.2 million in Other Non-Current Assets on the Consolidated Balance Sheet as of March 31, 2024 ($37.2 million as of December 31, 2023).

Other Income

	Three Months Ended
	March 31,
Other Income	2024	2023
Millions
Pension and Other Postretirement Benefit Plan Non-Service Credits (a)	$4.3	$2.0
Interest and Investment Income	1.9	1.1
AFUDC - Equity	1.2	0.5
Other	1.2	0.5
Total Other Income	$8.6	$4.1

(a)These are components of net periodic pension and other postretirement benefit cost other than service cost. (See Note 9. Pension and Other Postretirement Benefit Plans.)

Supplemental Statement of Cash Flows Information

	Three Months Ended
	March 31,
Supplemental Statement of Cash Flows Information	2024	2023
Millions
Cash Paid for Interest – Net of Amounts Capitalized	$25.7	$24.6
Noncash Investing and Financing Activities
Decrease in Accounts Payable for Capital Additions to Property, Plant and Equipment	$(5.9)	$(7.1)
Capitalized Asset Retirement Costs	$2.2	$2.4
AFUDC–Equity	$1.2	$0.5

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Regulatory Matters (Tables)

3 Months Ended

Mar. 31, 2024

Regulated Operations [Abstract]

Regulatory Assets and Liabilities

The recovery, refund or credit to rates for these regulatory assets and liabilities will occur over the periods either specified by the applicable regulatory authority or over the corresponding period related to the asset or liability.

Regulatory Assets and Liabilities	March 31, 2024	December 31, 2023
Millions
Current Regulatory Assets (a)
Fuel Adjustment Clause	$8.1	$8.7
Other	0.6	0.6
Total Current Regulatory Assets	$8.7	$9.3
Non-Current Regulatory Assets
Defined Benefit Pension and Other Postretirement Plans	$217.3	$218.6
Income Taxes	85.1	88.1
Asset Retirement Obligations	38.3	37.7
Cost Recovery Riders	27.6	33.8
Taconite Harbor	18.3	20.9
Manufactured Gas Plant	13.1	13.2
PPACA Income Tax Deferral	3.9	3.9
Fuel Adjustment Clause	2.1	5.0
Other	3.3	4.2
Total Non-Current Regulatory Assets	$409.0	$425.4
Current Regulatory Liabilities (b)
Fuel Adjustment Clause	$9.0	—
Provision for Interim Rate Refund	5.5	—
Transmission Formula Rates Refund	1.0	$1.5
Other	1.6	2.4
Total Current Regulatory Liabilities	$17.1	$3.9
Non-Current Regulatory Liabilities
Income Taxes	$302.3	$310.0
Wholesale and Retail Contra AFUDC	77.3	78.0
Plant Removal Obligations	69.3	67.0
Defined Benefit Pension and Other Postretirement Benefit Plans	45.5	48.6
Non-Jurisdictional Land Sales	35.1	30.2
Investment Tax Credits	13.5	13.6
Fuel Adjustment Clause	8.2	15.5
Boswell Units 1 and 2 Net Plant and Equipment	6.7	6.7
Other	6.1	4.4
Total Non-Current Regulatory Liabilities	$564.0	$574.0

(a)Current regulatory assets are presented within Prepayments and Other on the Consolidated Balance Sheet.

(b)Current regulatory liabilities are presented within Other Current Liabilities on the Consolidated Balance Sheet.

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Equity Investments (Tables)

3 Months Ended

Mar. 31, 2024

Equity Method Investments and Joint Ventures [Abstract]

Equity Method Investments

We account for our investment in ATC under the equity method of accounting.

ALLETE’s Investment in ATC
Millions
Equity Investment Balance as of December 31, 2023	$179.7
Cash Investments	1.6
Equity in ATC Earnings	5.7
Distributed ATC Earnings	(4.6)
Amortization of the Remeasurement of Deferred Income Taxes	0.3
Equity Investment Balance as of March 31, 2024	$182.7

We account for our investment in Nobles 2 under the equity method of accounting.

ALLETE’s Investment in Nobles 2
Millions
Equity Investment Balance as of December 31, 2023	$151.5
Equity in Nobles 2 Earnings (a)	(0.2)
Distributed Nobles 2 Earnings	(0.9)
Equity Investment Balance as of March 31, 2024	$150.4

(a)The Company also recorded earnings from net loss attributable to non-controlling interest of $3.0 million related to its investment in Nobles 2.

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Fair Value (Tables)

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Recurring Fair Value Measures

The estimated fair value of Cash and Cash Equivalents on the Consolidated Balance Sheet approximates the carrying amount and therefore is excluded from the recurring fair value measures in the following tables.

	Fair Value as of March 31, 2024
Recurring Fair Value Measures	Level 1	Level 2	Level 3	Total
Millions
Assets
Investments (a)
Available-for-sale – Equity Securities	$8.6	—	—	$8.6
Available-for-sale – Corporate and Governmental Debt Securities (b)	—	$6.5	—	6.5
Cash Equivalents	6.0	—	—	6.0
Total Fair Value of Assets	$14.6	$6.5	—	$21.1
Liabilities
Deferred Compensation (c)	—	$18.1	—	$18.1
Total Fair Value of Liabilities	—	$18.1	—	$18.1
	Fair Value as of December 31, 2023
Recurring Fair Value Measures	Level 1	Level 2	Level 3	Total
Millions
Assets
Investments (a)
Available-for-sale – Equity Securities	$8.7	—	—	$8.7
Available-for-sale – Corporate and Governmental Debt Securities	—	$6.0	—	6.0
Cash Equivalents	5.8	—	—	5.8
Total Fair Value of Assets	$14.5	$6.0	—	$20.5
Liabilities
Deferred Compensation (c)	—	$16.5	—	$16.5
Total Fair Value of Liabilities	—	$16.5	—	$16.5

(a)Included in Other Non-Current Assets on the Consolidated Balance Sheet.

(b)As of March 31, 2024, the aggregate amount of available-for-sale corporate and governmental debt securities maturing in one year or less was $1.7 million, in one year to less than three years was $2.7 million, in three years to less than five years was $1.6 million and in five or more years was $0.5 million.

(c)Included in Other Non-Current Liabilities on the Consolidated Balance Sheet.

Fair Value of Financial Instruments

The fair value of the item listed in the following table was based on quoted market prices for the same or similar instruments (Level 2).

Financial Instruments	Carrying Amount	Fair Value
Millions
Short-Term and Long-Term Debt (a)
March 31, 2024	$1,797.3	$1,646.8
December 31, 2023	$1,799.4	$1,670.6

(a)Excludes unamortized debt issuance costs.

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Short-Term and Long-Term Debt (Tables)

3 Months Ended

Mar. 31, 2024

Debt Disclosure [Abstract]

Schedule of Short-Term and Long-Term Debt

The following tables present the Company’s short-term and long-term debt as of March 31, 2024, and December 31, 2023:

March 31, 2024	Principal	Unamortized Debt Issuance Costs	Total
Millions
Short-Term Debt	$17.2	—	$17.2
Long-Term Debt	1,780.1	$(7.7)	1,772.4
Total Debt	$1,797.3	$(7.7)	$1,789.6

December 31, 2023	Principal	Unamortized Debt Issuance Costs	Total
Millions
Short-Term Debt	$111.5	$(0.1)	$111.4
Long-Term Debt	1,687.9	(8.0)	1,679.9
Total Debt	$1,799.4	$(8.1)	$1,791.3

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Earnings Per Share and Common Stock (Tables)

3 Months Ended

Mar. 31, 2024

Earnings Per Share [Abstract]

Reconciliation of Basic and Diluted Earnings Per Share

The difference between basic and diluted earnings per share, if any, arises from non-vested restricted stock units and performance share awards granted under our Executive Long-Term Incentive Compensation Plan.

Three Months Ended March 31,		2024			2023
Reconciliation of Basic and Diluted		Dilutive			Dilutive
Earnings Per Share	Basic	Securities	Diluted	Basic	Securities	Diluted
Millions Except Per Share Amounts
Net Income Attributable to ALLETE	$50.7		$50.7	$58.2		$58.2
Average Common Shares	57.6	0.1	57.7	57.3	—	57.3
Earnings Per Share	$0.88		$0.88	$1.02		$1.02

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Income Tax Expense (Tables)

3 Months Ended

Mar. 31, 2024

Income Tax Disclosure [Abstract]

Income Tax Expense

	Three Months Ended
	March 31,
	2024	2023
Millions
Current Income Tax Expense
Federal (a)	$3.5	$5.6
State	3.4	2.2
Total Current Income Tax Expense	$6.9	$7.8
Deferred Income Tax Expense (Benefit)
Federal (b)	$(5.0)	$(8.3)
State	2.4	2.1
Investment Tax Credit Amortization	(0.3)	(0.1)
Total Deferred Income Tax Benefit	$(2.9)	$(6.3)
Total Income Tax Expense	$4.0	$1.5

(a)For the three months ended March 31, 2024 and 2023, the federal current tax expense was partially offset by production tax credits.

(b)For the three months ended March 31, 2024 and 2023, the federal income tax benefit is primarily due to production tax credits.

Reconciliation of Taxes from Federal Statutory Rate to Total Income Tax Expense

In each quarter, the Company updates its estimate of the annual effective tax rate and if the estimated annual effective tax rate changes, the Company would make a cumulative adjustment in that quarter.

	Three Months Ended
Reconciliation of Taxes from Federal Statutory	March 31,
Rate to Total Income Tax Expense	2024		2023
Millions
Income Before Income Taxes	$41.0		$39.1
Statutory Federal Income Tax Rate	21	%	21	%
Income Taxes Computed at Statutory Federal Rate	$8.6		$8.2
Increase (Decrease) in Income Tax Due to:
State Income Taxes – Net of Federal Income Tax Benefit	4.6		3.4
Production Tax Credits (a)	(11.6)		(10.4)
Investment Tax Credits (a)	(0.3)		(2.2)
Regulatory Differences – Excess Deferred Tax	(3.5)		(2.8)
Non-Controlling Interest in Subsidiaries	2.8		3.8
AFUDC – Equity	(0.6)		(0.3)
Other	4.0		1.8
Total Income Tax Expense	$4.0		$1.5

(a)For the three months ended March 31, 2024 and 2023, the credits are presented net of any estimated discount on the sale of certain credits.

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Pension and Other Postretirement Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2024

Retirement Benefits [Abstract]

Components of Net Periodic Benefit Cost (Credit)

Components of Net Periodic Benefit Cost (Credit)	Pension		Other Postretirement
Three Months Ended March 31,	2024	2023	2024	2023
Millions
Service Cost	$1.6	$1.6	$0.4	$0.6
Non-Service Cost Components (a)
Interest Cost	9.7	10.1	1.0	1.5
Expected Return on Plan Assets	(11.2)	(10.9)	(2.8)	(2.8)
Amortization of Prior Service Credits	—	—	(2.9)	(1.8)
Amortization of Net Loss	1.6	1.4	(0.8)	(0.5)
Net Periodic Benefit Cost (Credit)	$1.7	$2.2	$(5.1)	$(3.0)

(a)These components of net periodic benefit cost (credit) are included in the line item “Other” under Other Income (Expense) on the Consolidated Statement of Income.

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Business Segments (Tables)

3 Months Ended

Mar. 31, 2024

Segment Reporting [Abstract]

Business Segments

We also present Corporate and Other which includes New Energy, a renewable energy development company, BNI Energy, our coal mining operations in North Dakota, ALLETE Properties, our legacy Florida real estate investment, along with our investment in Nobles 2, South Shore Energy, our non-rate regulated, Wisconsin subsidiary developing NTEC, other business development and corporate expenditures, unallocated interest expense, a small amount of non-rate base generation, land holdings in Minnesota, and earnings on cash and investments.

NOTE 10. BUSINESS SEGMENTS (Continued)

	Three Months Ended
	March 31,
	2024	2023
Millions
Operating Revenue
Regulated Operations
Residential	$51.5	$49.4
Commercial	49.7	47.7
Municipal	9.0	8.9
Industrial	159.5	144.9
Other Power Suppliers	40.0	35.9
Other	28.6	25.8
Total Regulated Operations	338.3	312.6
ALLETE Clean Energy
Long-term PSA	17.8	18.4
Sale of Wind Energy Facilities	—	181.8
Other	1.3	1.3
Total ALLETE Clean Energy	19.1	201.5
Corporate and Other
Long-term Contract	25.4	25.5
Sale of Renewable Development Projects	13.9	19.8
Other	6.6	5.5
Total Corporate and Other	45.9	50.8
Total Operating Revenue	$403.3	$564.9
Net Income Attributable to ALLETE
Regulated Operations	$44.2	$40.6
ALLETE Clean Energy	3.8	8.5
Corporate and Other	2.7	9.1
Total Net Income Attributable to ALLETE	$50.7	$58.2

	March 31, 2024	December 31, 2023
Millions
Assets
Regulated Operations	$4,345.1	$4,335.0
ALLETE Clean Energy	1,580.0	1,594.1
Corporate and Other	679.5	727.3
Total Assets	$6,604.6	$6,656.4

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Operations and Significant Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Cash, Cash Equivalents and Restricted Cash [Abstract]
Cash and Cash Equivalents	$ 32.0	$ 71.9	$ 29.9	$ 36.4
Restricted Cash included in Prepayments and Other	5.9	5.1	7.4	1.5
Restricted Cash included in Other Non-Current Assets	2.4	2.4	2.3	2.3
Cash, Cash Equivalents and Restricted Cash on the Consolidated Statement of Cash Flows	$ 40.3	$ 79.4	$ 39.6	$ 40.2

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Operations and Significant Accounting Policies - Inventories (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Fuel	$ 30.2	$ 27.2
Materials and Supplies	119.0	115.7
Renewable Energy Facilities Under Development	33.5	32.5
Inventories – Net	$ 182.7	$ 175.4

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Operations and Significant Accounting Policies - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Non-Controlling Interest Details [Line Items]
Goodwill	$ 154.9		$ 154.9
Net Loss Attributable to Non-Controlling Interest	$ (13.7)	$ (20.6)

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Operations and Significant Accounting Policies - Other Non-Current Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Other Postretirement Benefit Plans	$ 104.6	$ 106.3
Contract Assets	17.9	18.5
Operating Lease Right-of-use Assets	11.3	10.7
ALLETE Properties	10.7	10.8
Restricted Cash	2.4	2.4	$ 2.3	$ 2.3
Finance Lease Right-of-use Assets	2.0	2.1
Other	115.9	112.1
Total Other Non-Current Assets	$ 264.8	$ 262.9

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Operations and Significant Accounting Policies - Other Current Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
PSAs	$ 6.0	$ 6.0
Customer Deposits	5.7	7.4
Provision for Interim Rate Refund	5.5	0.0
Operating Lease Liabilities	3.1	3.0
Finance Lease Liabilities	0.4	0.4
Other	59.5	75.1
Total Other Current Liabilities	$ 80.2	$ 91.9

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Operations and Significant Accounting Policies - Other Non-Current Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Business Segments [Line Items]
Asset Retirement Obligation	$ 206.1	$ 202.9
PSAs	19.5	20.9
Operating Lease Liabilities	8.3	7.7
Finance Lease Liabilities	1.5	1.6
Other	32.6	31.2
Other Non-Current Liabilities	268.0	264.3
BNI Energy
Business Segments [Line Items]
Other Receivables	$ 37.2	$ 37.2

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Operations and Significant Accounting Policies - Other Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Other Income
Total Other Income	$ 8.6	$ 4.1
Pension and Other Postretirement Benefit Plan Non-Service Credits
Other Income
Total Other Income	4.3	2.0
Interest and Investment Income
Other Income
Total Other Income	1.9	1.1
AFUDC - Equity
Other Income
Total Other Income	1.2	0.5
Other
Other Income
Total Other Income	$ 1.2	$ 0.5

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Operations and Significant Accounting Policies - Supplemental Statement of Cash Flows Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash Paid for Interest – Net of Amounts Capitalized	$ 25.7	$ 24.6
Noncash Investing and Financing Activities
Decrease in Accounts Payable for Capital Additions to Property, Plant and Equipment	(5.9)	(7.1)
Capitalized Asset Retirement Costs	2.2	2.4
AFUDC–Equity	$ 1.2	$ 0.5

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Regulatory Matters - Electric Rates (Details) - USD ($) $ in Thousands						3 Months Ended
	May 03, 2024	Apr. 01, 2024	Mar. 29, 2024	Dec. 19, 2023	Nov. 01, 2023	Mar. 31, 2024	Sep. 30, 2023	Mar. 31, 2023	Dec. 31, 2023
Regulatory Matters [Line Items]
Regulatory Assets						$ 409,000			$ 425,400
Regulatory Liabilities						564,000			$ 574,000
ECO Annual Filing Member | MPUC | Minnesota Power
Regulatory Matters [Line Items]
Revenue from cost recovery riders and other regulatory programs							$ 2,200
ECO Annual Filing Member | MPUC | Minnesota Power | Subsequent Event
Regulatory Matters [Line Items]
Revenue from cost recovery riders and other regulatory programs		$ 2,200
Electric Rates | Fuel Adjustment Clause 2023 | MPUC | Minnesota Power
Regulatory Matters [Line Items]
Regulatory Assets						13,000
Retail Customers | Electric Rates | Current Cost Recovery Rider | MPUC | Minnesota Power
Regulatory Matters [Line Items]
Revenue from cost recovery riders and other regulatory programs						8,300		$ 16,400
Retail Customers | Electric Rates | 2024 Minnesota General Rate Case | MPUC | Minnesota Power
Regulatory Matters [Line Items]
Requested rate increase percent					12.00%
Approved rate increase				$ 64,000
Requested return on equity					10.30%
Requested equity capital structure					53.00%
Annual additional revenue generated from requested final rate increase					$ 89,000
Regulatory liabilities						$ 5,500
Retail Customers | Electric Rates | 2024 Minnesota General Rate Case | MPUC | Minnesota Power | Subsequent Event
Regulatory Matters [Line Items]
Requested return on equity	9.78%
Annual additional revenue generated from requested final rate increase	$ 33,970
Retail Customers | Electric Rates | 2024 Wisconsin General Rate Case | PSCW | SWL&P
Regulatory Matters [Line Items]
Requested rate increase percent			5.90%
Requested return on equity			10.00%
Requested equity capital structure			55.00%
Annual additional revenue generated from requested final rate increase			$ 7,300

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Regulatory Matters - Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Regulatory Assets and Liabilities [Line Items]
Total Current Regulatory Assets	$ 8.7	$ 9.3
Total Non-Current Regulatory Assets	409.0	425.4
Total Current Regulatory Liabilities	17.1	3.9
Total Non-Current Regulatory Liabilities	564.0	574.0
Fuel Adjustment Clause
Regulatory Assets and Liabilities [Line Items]
Total Current Regulatory Liabilities	9.0	0.0
Total Non-Current Regulatory Liabilities	8.2	15.5
Provision for Interim Rate Refund
Regulatory Assets and Liabilities [Line Items]
Total Current Regulatory Liabilities	5.5	0.0
Transmission Formula Rates Refund
Regulatory Assets and Liabilities [Line Items]
Total Current Regulatory Liabilities	1.0	1.5
Other
Regulatory Assets and Liabilities [Line Items]
Total Current Regulatory Liabilities	1.6	2.4
Total Non-Current Regulatory Liabilities	6.1	4.4
Income Taxes
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Liabilities	302.3	310.0
Wholesale and Retail Contra AFUDC
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Liabilities	77.3	78.0
Plant Removal Obligations
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Liabilities	69.3	67.0
Defined Benefit Pension and Other Postretirement Benefit Plans
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Liabilities	45.5	48.6
Non-Jurisdictional Land Sales
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Liabilities	35.1	30.2
Investment Tax Credits
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Liabilities	13.5	13.6
Boswell Units 1 and 2 Net Plant and Equipment
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Liabilities	6.7	6.7
Fuel Adjustment Clause
Regulatory Assets and Liabilities [Line Items]
Total Current Regulatory Assets	8.1	8.7
Total Non-Current Regulatory Assets	2.1	5.0
Other
Regulatory Assets and Liabilities [Line Items]
Total Current Regulatory Assets	0.6	0.6
Total Non-Current Regulatory Assets	3.3	4.2
Defined Benefit Pension and Other Postretirement Benefit Plans
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Assets	217.3	218.6
Income Taxes
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Assets	85.1	88.1
Asset Retirement Obligations
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Assets	38.3	37.7
Cost Recovery Riders
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Assets	27.6	33.8
Taconite Harbor
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Assets	18.3	20.9
Manufactured Gas Plant
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Assets	13.1	13.2
PPACA Income Tax Deferral
Regulatory Assets and Liabilities [Line Items]
Total Non-Current Regulatory Assets	$ 3.9	$ 3.9

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Equity Investments - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) MW
Wind Turbine Generators | Tenaska | Tenaska PPA | Minnesota Power
Investments In ATC [Roll Forward]
Generating capacity counterparty owned (MegaWatt) | MW	250
Long-term contract for purchase of electric power	20 years
ATC
Investments In ATC [Roll Forward]
Ownership percentage	8.00%
Authorized return on equity	10.02%
Authorized return on equity, including incentive adder	10.52%
Basis point incentive adder	0.50%
Approximate annual reduction in pretax income for FERC proposal to limit incentive adder, Allete's proportionate share | $	$ 1
Nobles 2
Investments In ATC [Roll Forward]
Ownership percentage	49.00%

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Equity Investments - Investment in ATC (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Investments In ATC [Roll Forward]
Equity Investment Balance as of December 31, 2023	$ 331.2
Cash Investments	1.6	$ 0.8
Equity Earnings	5.5	6.0
Equity Investment Balance as of March 31, 2024	333.1
Net Loss Attributable to Non-Controlling Interest	(13.7)	$ (20.6)
ATC
Investments In ATC [Roll Forward]
Equity Investment Balance as of December 31, 2023	179.7
Cash Investments	1.6
Equity Earnings	5.7
Distributed earnings	(4.6)
Amortization of the Remeasurement of Deferred Income Taxes	0.3
Equity Investment Balance as of March 31, 2024	182.7
Nobles 2
Investments In ATC [Roll Forward]
Equity Investment Balance as of December 31, 2023	151.5
Equity Earnings	(0.2)
Distributed earnings	(0.9)
Equity Investment Balance as of March 31, 2024	150.4
Net Loss Attributable to Non-Controlling Interest	$ 3.0

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Fair Value - Recurring Fair Value Measures (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Liabilities
Aggregate amount of available-for-sale corporate and governmental debt securities maturing in one year	$ 1.7
Aggregate amount of available-for-sale corporate and governmental debt securities maturing after one year through three years	2.7
Aggregate amount of available-for-sale corporate and governmental debt securities maturing after one year through three years after three years through five years	1.6
Aggregate amount of available-for-sale corporate and governmental debt securities maturing after one year through three years after three years through five years after five years	0.5
Recurring Fair Value Measures
Investments [Abstract]
Available-for-sale – Equity Securities	8.6	$ 8.7
Available-for-sale – Corporate and Governmental Debt Securities	6.5	6.0
Cash Equivalents	6.0	5.8
Total Fair Value of Assets	21.1	20.5
Liabilities
Deferred compensation	18.1	16.5
Total Fair Value of Liabilities	18.1	16.5
Recurring Fair Value Measures | Level 1
Investments [Abstract]
Available-for-sale – Equity Securities	8.6	8.7
Available-for-sale – Corporate and Governmental Debt Securities	0.0	0.0
Cash Equivalents	6.0	5.8
Total Fair Value of Assets	14.6	14.5
Liabilities
Deferred compensation	0.0	0.0
Total Fair Value of Liabilities	0.0	0.0
Recurring Fair Value Measures | Level 2
Investments [Abstract]
Available-for-sale – Equity Securities	0.0	0.0
Available-for-sale – Corporate and Governmental Debt Securities	6.5	6.0
Cash Equivalents	0.0	0.0
Total Fair Value of Assets	6.5	6.0
Liabilities
Deferred compensation	18.1	16.5
Total Fair Value of Liabilities	18.1	16.5
Recurring Fair Value Measures | Level 3
Investments [Abstract]
Available-for-sale – Equity Securities	0.0	0.0
Available-for-sale – Corporate and Governmental Debt Securities	0.0	0.0
Cash Equivalents	0.0	0.0
Total Fair Value of Assets	0.0	0.0
Liabilities
Deferred compensation	0.0	0.0
Total Fair Value of Liabilities	$ 0.0	$ 0.0

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Fair Value - Fair Value of Financial Instruments and Assets Measured on a Nonrecurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair Value of Financial Instruments [Line Items]
Short-term and long-term debt - carrying amount	$ 1,797.3	$ 1,799.4
Level 2
Fair Value of Financial Instruments [Line Items]
Short-term and long-term debt - fair value	$ 1,646.8	$ 1,670.6

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Short-Term and Long-Term Debt - Schedule of Short-Term and Long-Term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Principal
Short-Term Debt	$ 17.2	$ 111.5
Long-Term Debt	1,780.1	1,687.9
Total Debt	1,797.3	1,799.4
Unamortized Debt Issuance Costs
Short-Term Debt	0.0	(0.1)
Long-Term Debt	(7.7)	(8.0)
Total Debt	(7.7)	(8.1)
Total
Short-Term Debt	17.2	111.4
Long-Term Debt	1,772.4	1,679.9
Total Debt	$ 1,789.6	$ 1,791.3

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Short-Term and Long-Term Debt - Narrative (Details) $ in Millions	Apr. 23, 2024 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Actual ratio of indebtedness to total capitalization		0.36
ALLETE Bonds 4.98% Due April 2033 | Subsequent Event
Debt Instrument [Line Items]
Proceeds from issuance of first mortgage bond	$ 100.0
Interest rate	5.72%
Credit Agreement | Line of Credit
Debt Instrument [Line Items]
Letters of credit outstanding		$ 19.4	$ 19.4
Line of credit draw outstanding		$ 94.0	$ 34.1
Minimum
Debt Instrument [Line Items]
Required ratio of indebtedness to total capitalization		0.65
Maximum
Debt Instrument [Line Items]
Required ratio of indebtedness to total capitalization		1.00

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Commitments, Guarantees and Contingencies - Power Purchase Agreements (Details) - Square Butte PPA - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Square Butte
Power Purchase Agreements [Line Items]
PPA counterparty total debt outstanding	$ 162.6
Square Butte | Minnesota Power
Power Purchase Agreements [Line Items]
Cost of power purchased	22.9	$ 22.1
Pro rata share of PPA counterparty interest expense	$ 1.3	$ 1.3
Square Butte | Minnesota Power | Square Butte Coal-Fired Unit
Power Purchase Agreements [Line Items]
Expected output entitlement	50.00%
Minnkota Power | Minnesota Power | Square Butte Coal-Fired Unit | Minnkota Power PSA
Power Purchase Agreements [Line Items]
Expected output entitlement	41.00%		37.00%

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Commitments, Guarantees and Contingencies - Environmental Matters (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Coal Combustion Residuals | Minnesota Power
Environmental Matters [Line Items]
Expected period for costs of compliance	12 years
Coal Combustion Residuals | Minimum | Minnesota Power
Environmental Matters [Line Items]
Estimated costs of compliance	$ 65
Coal Combustion Residuals | Maximum | Minnesota Power
Environmental Matters [Line Items]
Estimated costs of compliance	120
Manufactured Gas Plant | SWL&P | Superior, WI
Environmental Matters [Line Items]
Redemption cost liability	$ 1

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Commitments, Guarantees and Contingencies - Other Matters (Details) - USD ($) $ in Millions	Apr. 30, 2024	Mar. 31, 2024
Subsequent Event
Guarantor Obligations [Line Items]
Production tax credits sold	$ 14.0
ALLETE, Inc. | Standby Letters of Credit
Guarantor Obligations [Line Items]
Letters of credit outstanding		$ 150.1
Regulated Operations | Standby Letters of Credit
Guarantor Obligations [Line Items]
Letters of credit outstanding		25.4
ALLETE Clean Energy | Standby Letters of Credit
Guarantor Obligations [Line Items]
Letters of credit outstanding		80.6
BNI Energy Reclamation Liability
Guarantor Obligations [Line Items]
Estimated obligation		82.1
BNI Energy Reclamation Liability | Surety Bonds
Guarantor Obligations [Line Items]
Collateral		82.4
ALLETE South Wind | Standby Letters of Credit
Guarantor Obligations [Line Items]
Letters of credit outstanding		10.1
South Shore Energy | Standby Letters of Credit
Guarantor Obligations [Line Items]
Letters of credit outstanding		$ 29.7

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Earnings Per Share and Common Stock (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Basic
Net Income Attributable to ALLETE	$ 50.7	$ 58.2
Average common shares (in shares)	57.6	57.3
Earnings Per Share (in usd per share)	$ 0.88	$ 1.02
Diluted
Net Income Attributable to ALLETE	$ 50.7	$ 58.2
Average common shares adjustment (in shares)	0.1	0.0
Average common shares (in shares)	57.7	57.3
Earnings Per Share (in usd per share)	$ 0.88	$ 1.02

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Income Tax Expense - Schedule of Income Tax Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Current Income Tax Expense
Federal	$ 3.5	$ 5.6
State	3.4	2.2
Total Current Income Tax Expense	6.9	7.8
Deferred Income Tax Expense (Benefit)
Federal	(5.0)	(8.3)
State	2.4	2.1
Investment Tax Credit Amortization	(0.3)	(0.1)
Total Deferred Income Tax Benefit	(2.9)	(6.3)
Total Income Tax Expense	$ 4.0	$ 1.5

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Income Tax Expense - Reconciliation of Taxes from Federal Statutory Rate to Total Income Tax Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reconciliation of Taxes from Federal Statutory Rate to Total Income Tax Expense [Abstract]
Income Before Income Taxes	$ 41.0	$ 39.1
Income Taxes Computed at Statutory Federal Rate	8.6	8.2
Increase (Decrease) in Income Tax Due to:
State Income Taxes – Net of Federal Income Tax Benefit	4.6	3.4
Production tax credits	(11.6)	(10.4)
Investment tax credits	(0.3)	(2.2)
Regulatory Differences – Excess Deferred Tax	(3.5)	(2.8)
Non-Controlling Interest in Subsidiaries	2.8	3.8
AFUDC – Equity	(0.6)	(0.3)
Other	4.0	1.8
Total Income Tax Expense	$ 4.0	$ 1.5

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Income Tax Expense - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Effective tax rate	9.70%	3.80%
Gross unrecognized tax benefits	$ 1.1		$ 1.1
Gross unrecognized tax benefits that would favorably impact effective income tax rate	$ 0.6

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Pension and Other Postretirement Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pension
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service Cost	$ 1.6	$ 1.6
Interest Cost	9.7	10.1
Expected Return on Plan Assets	(11.2)	(10.9)
Amortization of Prior Service Credits	0.0	0.0
Amortization of Net Loss	1.6	1.4
Net Periodic Benefit Cost (Credit)	1.7	2.2
Other Postretirement
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service Cost	0.4	0.6
Interest Cost	1.0	1.5
Expected Return on Plan Assets	(2.8)	(2.8)
Amortization of Prior Service Credits	(2.9)	(1.8)
Amortization of Net Loss	(0.8)	(0.5)
Net Periodic Benefit Cost (Credit)	$ (5.1)	$ (3.0)

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Pension and Other Postretirement Benefit Plans - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pension
Pension and Other Postretirement Benefit Plans [Line Items]
Employer contributions	$ 25.0	$ 6.5
Expected future employer contributions	0.0
Other Postretirement
Pension and Other Postretirement Benefit Plans [Line Items]
Employer contributions	0.0	$ 0.0
Expected future employer contributions	$ 0.0

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Business Segments - Narrative (Details)	3 Months Ended
	Mar. 31, 2024 segment
Business Segments [Line Items]
Number of reportable segments	2
Regulated Operations
Business Segments [Line Items]
Number of operating segments	3

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Business Segments - (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Business Segments [Line Items]
Total Operating Revenue	$ 403.3	$ 564.9
Net Income Attributable to ALLETE	50.7	58.2
Assets	6,604.6		$ 6,656.4
Corporate and Other
Business Segments [Line Items]
Total Operating Revenue	403.3	564.9
Regulated Operations
Business Segments [Line Items]
Net Income Attributable to ALLETE	44.2	40.6
Assets	4,345.1		4,335.0
Regulated Operations | Operating Segments
Business Segments [Line Items]
Total Operating Revenue	338.3	312.6
Regulated Operations | Residential | Operating Segments
Business Segments [Line Items]
Operating Revenue	51.5	49.4
Regulated Operations | Commercial | Operating Segments
Business Segments [Line Items]
Operating Revenue	49.7	47.7
Regulated Operations | Municipal | Operating Segments
Business Segments [Line Items]
Operating Revenue	9.0	8.9
Regulated Operations | Industrial | Operating Segments
Business Segments [Line Items]
Operating Revenue	159.5	144.9
Regulated Operations | Other Power Suppliers | Operating Segments
Business Segments [Line Items]
Operating Revenue	40.0	35.9
Regulated Operations | Other | Operating Segments
Business Segments [Line Items]
Operating Revenue	28.6	25.8
ALLETE Clean Energy
Business Segments [Line Items]
Net Income Attributable to ALLETE	3.8	8.5
Assets	1,580.0		1,594.1
ALLETE Clean Energy | Operating Segments
Business Segments [Line Items]
Total Operating Revenue	19.1	201.5
ALLETE Clean Energy | Long-term PSA | Operating Segments
Business Segments [Line Items]
Operating Revenue	17.8	18.4
ALLETE Clean Energy | Sale of Wind Energy Facilities | Operating Segments
Business Segments [Line Items]
Operating Revenue	0.0	181.8
ALLETE Clean Energy | Other | Operating Segments
Business Segments [Line Items]
Operating revenue, other than customer revenue	1.3	1.3
Corporate and Other
Business Segments [Line Items]
Net Income Attributable to ALLETE	2.7	9.1
Assets	679.5		$ 727.3
Corporate and Other | Corporate and Other
Business Segments [Line Items]
Total Operating Revenue	45.9	50.8
Corporate and Other | Long-term Contract | Corporate and Other
Business Segments [Line Items]
Operating Revenue	25.4	25.5
Corporate and Other | Sale of Renewable Development Projects | Corporate and Other
Business Segments [Line Items]
Operating Revenue	13.9	19.8
Corporate and Other | Other | Corporate and Other
Business Segments [Line Items]
Operating Revenue	$ 6.6	$ 5.5

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Subsequent Event - Agreement and Plan of Merger - Narrative (Details) - Alloy Parent and Alloy Merger Sub - Forecast $ / shares in Units, $ in Millions	8 Months Ended
	Dec. 31, 2024 USD ($) $ / shares
Subsequent Event
Subsequent Event [Line Items]
Conversion price, cash (in usd per share) | $ / shares	$ 67.00
Equity value of ALLETE common stock acquired	$ 3,900
Alloy Parent
Subsequent Event [Line Items]
Required amount to purchase of preferred stock	$ 300