
Regulatory Clause	Balance Sheet Line Item	March 31, 2024		December 31, 2023
		(in millions)
Alabama Power
Rate CNP Compliance	Other regulatory assets, current	$	8	$	8
	Other regulatory assets, deferred	19		25
Rate CNP PPA	Other regulatory assets, current	18		18
	Other regulatory assets, deferred	82		85
Rate ECR	Regulatory assets – under recovered retail fuel clause revenues	173		246



Georgia Power
Fuel Cost Recovery	Receivables – under recovered retail fuel clause revenues	$	679	$	694
	Deferred under recovered retail fuel clause revenues	1,044		1,211

Mississippi Power
Fuel Cost Recovery(*)	Receivables – customer accounts, net	$	20	$	—
	Deferred under recovered retail fuel clause revenues	—		50
	Over recovered retail fuel clause revenues	—		27

Ad Valorem Tax	Other regulatory assets, deferred	13		12


Southern Company Gas

Natural Gas Cost Recovery	Natural gas cost over recovery	$	150	$	214

(*)Mississippi Power also has wholesale MRA and Market Based (MB) fuel cost recovery factors. At March 31, 2024 and December 31, 2023, wholesale MRA fuel costs were over recovered $10 million and $5 million, respectively, and were included in other current liabilities on Mississippi Power's balance sheets. The wholesale MB fuel cost recovery was immaterial for both periods presented.

Alabama Power currently expects to retire Plant Greene County Units 1 and 2 (300 MWs based on 60% ownership) by the end of 2028. Alabama Power and Mississippi Power continue to evaluate operating conditions and business needs relevant to the anticipated retirement of Plant Greene County Units 1 and 2. Additionally, the unit retirements require the completion by Alabama Power of transmission and system reliability improvements, as well as agreement by Alabama Power.

On April 16, 2024, the Georgia PSC approved Georgia Power's updated IRP (2023 IRP Update) as modified by a stipulated agreement among Georgia Power, the staff of the Georgia PSC, and certain intervenors. In the 2023 IRP Update decision, the Georgia PSC approved the following requests:

•Authority to develop, own, and operate up to 1,400 MWs from three simple cycle combustion turbines at Plant Yates with the recoverable costs not to exceed the certified amount, which is projected to be approved by the Georgia PSC in the second half of 2024. In doing so, the Georgia PSC recognized the potential for circumstances beyond Georgia Power's control that could cause the project costs to exceed the certified amount, in which case Georgia Power would provide documentation to the Georgia PSC to explain and justify potential recovery of the additional costs.

•Authority to develop, own, and operate up to 500 MWs of battery energy storage facilities, including storage systems collocated with existing Georgia Power-owned solar facilities, as well as the issuance of a request for proposals for an additional 500 MWs of battery energy storage facilities.

On January 12, 2024, Georgia Power entered into an Agreement for Engineering, Procurement, and Construction with Mitsubishi Power Americas, Inc. and Black & Veatch Construction, Inc. to construct three 442-MW simple cycle combustion turbine units at Plant Yates (Plant Yates Units 8, 9, and 10), which are projected to be placed in service in the fourth quarter 2026, the second quarter 2027, and the third quarter 2027, respectively. The ultimate outcome of this matter cannot be determined at this time.

On March 7, 2024, the FERC approved the sale of transmission line assets under the integrated transmission system agreement, with a net book value of $230 million which is classified as held for sale at March 31, 2024 and included in other current assets on Southern Company's and Georgia Power's balance sheets. Subsequent to March 31, 2024, the sale, with a purchase price of $341 million, was completed resulting in a pre-tax gain of approximately $110 million ($81 million after tax) to be recorded in the second quarter 2024.

In 2009, the Georgia PSC certified construction of Plant Vogtle Units 3 and 4, in which Georgia Power holds a 45.7% ownership interest. In 2012, the NRC issued the related combined construction and operating licenses, which allowed full construction of the two AP1000 nuclear units (with electric generating capacity of approximately 1,100 MWs each) and related facilities to begin.

Georgia Power placed Unit 3 in service on July 31, 2023. On February 14, 2024, Unit 4 achieved self-sustaining nuclear fission, commonly referred to as initial criticality, and, on March 1, 2024, the generator successfully synchronized to the power grid and generated electricity for the first time. Georgia Power placed Unit 4 in service on April 29, 2024.

See Note 2 to the financial statements under "Georgia Power – Nuclear Construction" in Item 8 of the Form 10-K for additional information on Plant Vogtle Units 3 and 4 construction and cost recovery. See Note 8 to the financial statements under "Long-term Debt – DOE Loan Guarantee Borrowings" in Item 8 of the Form 10-K for information on the Amended and Restated Loan Guarantee Agreement, including applicable covenants, events of default, and mandatory prepayment events.

Georgia Power's net capital costs incurred through March 31, 2024 in connection with Plant Vogtle Units 3 and 4, and its approximate proportionate share of additional capital costs to be incurred after March 31, 2024, including completion of testing and start-up for Unit 4 through April 2024 and demobilizing the site after Unit 4's in-service date, is as follows:

(a)Includes approximately $610 million of costs that are not shared with the other Vogtle Owners, including $33 million of construction monitoring costs, and approximately $567 million of incremental costs under the cost-sharing provisions of the Vogtle Joint Ownership Agreements (as defined below). Excludes financing costs expected to be capitalized through AFUDC of approximately $440 million, of which $435 million had been accrued through March 31, 2024.

In September 2022, Georgia Power and MEAG Power reached an agreement to resolve a dispute regarding the cost-sharing and tender provisions of the joint ownership agreements for Plant Vogtle Units 3 and 4, as amended (Vogtle Joint Ownership Agreements). Under the terms of the agreement, among other items, (i) MEAG Power will not exercise its tender option and will retain its full ownership interest in Plant Vogtle Units 3 and 4; (ii) Georgia Power will reimburse a portion of MEAG Power's costs of construction for Plant Vogtle Units 3 and 4 as such costs are incurred and with no further adjustment for force majeure costs, which payments will total approximately $92 million based on the current project capital cost forecast; and (iii) Georgia Power will reimburse 20% of MEAG Power's costs of construction with respect to any amounts over the current project capital cost forecast, with no further adjustment for force majeure costs.

In October 2023, Georgia Power reached agreements with both OPC and Dalton to resolve its respective dispute with each of OPC and Dalton regarding the cost-sharing and tender provisions of the Vogtle Joint Ownership Agreements. Under the terms of the agreements with OPC and Dalton, among other items, (i) each of OPC and Dalton retracted its exercise of the tender option and will retain its full ownership interest in Plant Vogtle Units 3 and 4, (ii) Georgia Power made payments immediately after execution of the agreements of $308 million and $17 million to OPC and Dalton, respectively, representing payment for a portion of each of OPC's and Dalton's costs of construction for Plant Vogtle Units 3 and 4 previously incurred, (iii) Georgia Power will pay a portion of each of OPC's and Dalton's further costs of construction for Plant Vogtle Units 3 and 4 as such costs are incurred and with no further adjustment for force majeure costs, which payments will be in an aggregate amount of approximately $105 million and $6 million for OPC and Dalton, respectively, based on the current project capital cost forecast, and (iv) Georgia Power will pay 66% of each of OPC's and Dalton's costs of construction with respect to any amounts above the current project capital cost forecast, with no further adjustment for force majeure costs.

Georgia Power increased annual retail base rates by $318 million effective August 1, 2023 based on the in-service date of July 31, 2023 for Unit 3. Financing costs (debt and equity) on the remaining portion of the total Unit 3 and the common facilities construction costs continued to be recovered through the NCCR tariff or deferred. Georgia

Power deferred as a regulatory asset the debt component of financing costs ($22 million at March 31, 2024) as well as the remaining depreciation expense ($28 million at March 31, 2024) until Unit 4 costs were placed in retail base rates as described below. The equity component of financing costs ($38 million at March 31, 2024) represents an unrecognized ratemaking amount that is not reflected on Georgia Power's balance sheets. This amount will be recognized in Georgia Power's income statements in the periods it is billable to customers.

After considering construction and capital costs already in retail base rates of $2.1 billion and $362 million of associated retail rate base items for Unit 3 and common facilities, Georgia Power included in retail rate base the remaining $5.462 billion of construction and capital costs as well as $647 million of associated retail rate base items effective with the April 29, 2024 in-service date for Unit 4, pursuant to the approved Prudency Stipulation. Annual retail base revenues increased approximately $730 million and the average retail base rates were adjusted by approximately 5% (net of the elimination of the NCCR tariff described below) effective May 1, 2024.

Reductions to the ROE used to calculate the NCCR tariff (pursuant to prior Georgia PSC orders) negatively impacted earnings by approximately $310 million in 2023 and $60 million in the first quarter 2024 and are projected to have additional negative earnings impact of approximately $20 million in the second quarter 2024. Further, as included in the approved Prudency Stipulation, since commercial operation for Unit 4 was not achieved by March 31, 2024, Georgia Power's ROE used to determine the NCCR tariff and calculate AFUDC was reduced to zero effective April 1, 2024, which is projected to result in an estimated negative impact to earnings of approximately $10 million (for one month) in the second quarter 2024 based on the April 29, 2024 in-service date. Effective May 1, 2024, following commercial operation of Unit 4, Georgia Power's NCCR tariff was eliminated and related financing costs are included in Georgia Power's general retail revenue requirements and collected through retail base rates.

On April 26, 2024, Mississippi Power filed its 2024 IRP with the Mississippi PSC. The filing includes a schedule to retire Plant Watson Unit 4 (268 MWs) and Plant Greene County Units 1 and 2 (206 MWs based on 40% ownership) and to retire early Plant Daniel Units 1 and 2 (502 MWs based on 50% ownership), all by the end of 2028, which is consistent with the completion of Mississippi Power's affiliate PPA with Georgia Power. The Plant Greene County unit retirements require the completion by Alabama Power of transmission and system reliability improvements, as well as agreement by Alabama Power.

The remaining net book value of Plant Daniel Units 1 and 2 was approximately $485 million at March 31, 2024 and Mississippi Power is continuing to depreciate these units using the current approved rates. Mississippi Power expects to reclassify the net book value remaining at retirement to a regulatory asset to be amortized over a period to

On March 29, 2024, Mississippi Power filed a request with the FERC for an $8 million increase in annual wholesale base revenues under the MRA tariff and requested an effective date of May 29, 2024. On April 19, 2024, Cooperative Energy challenged the new rates in a filing with the FERC. The ultimate outcome of this matter cannot be determined at this time.