Regulatory Matters

6 Months Ended

Jun. 30, 2023

Public Utilities, General Disclosures [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Assets retired early - In May 2023, IPL retired the coal-fired Lansing Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. The related regulatory asset balance as of June 30, 2023 was $226 million, which is currently included in IPL’s rate base and IPL is earning a return of and a return on the remaining balance. Continued recovery of the remaining net book value of Lansing is expected to be addressed in future IPL rate reviews.

Derivatives - Refer to Note 11 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the six months ended June 30, 2023, which resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

WPL’s West Riverside liquidated damages - Pursuant to PSCW authorization, WPL’s amortization of liquidated damages related to West Riverside construction procurement contracts was used to offset increases in WPL’s retail electric 2022/2023 Test Period revenue requirement, which resulted in decreases in regulatory liabilities on Alliant Energy’s and WPL’s balance sheets and decreases in depreciation and amortization expenses in Alliant Energy’s and WPL’s income statements for the three and six months ended June 30, 2023.

IPL [Member]

Public Utilities, General Disclosures [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Assets retired early - In May 2023, IPL retired the coal-fired Lansing Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. The related regulatory asset balance as of June 30, 2023 was $226 million, which is currently included in IPL’s rate base and IPL is earning a return of and a return on the remaining balance. Continued recovery of the remaining net book value of Lansing is expected to be addressed in future IPL rate reviews.

Derivatives - Refer to Note 11 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the six months ended June 30, 2023, which resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

WPL’s West Riverside liquidated damages - Pursuant to PSCW authorization, WPL’s amortization of liquidated damages related to West Riverside construction procurement contracts was used to offset increases in WPL’s retail electric 2022/2023 Test Period revenue requirement, which resulted in decreases in regulatory liabilities on Alliant Energy’s and WPL’s balance sheets and decreases in depreciation and amortization expenses in Alliant Energy’s and WPL’s income statements for the three and six months ended June 30, 2023.

WPL [Member]

Public Utilities, General Disclosures [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Assets retired early - In May 2023, IPL retired the coal-fired Lansing Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. The related regulatory asset balance as of June 30, 2023 was $226 million, which is currently included in IPL’s rate base and IPL is earning a return of and a return on the remaining balance. Continued recovery of the remaining net book value of Lansing is expected to be addressed in future IPL rate reviews.

Derivatives - Refer to Note 11 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the six months ended June 30, 2023, which resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

WPL’s West Riverside liquidated damages - Pursuant to PSCW authorization, WPL’s amortization of liquidated damages related to West Riverside construction procurement contracts was used to offset increases in WPL’s retail electric 2022/2023 Test Period revenue requirement, which resulted in decreases in regulatory liabilities on Alliant Energy’s and WPL’s balance sheets and decreases in depreciation and amortization expenses in Alliant Energy’s and WPL’s income statements for the three and six months ended June 30, 2023.