Alliant Energy 10-Q 2024-03-31

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q

☒ 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

Name of Registrant, State of Incorporation, Address of Principal Executive Offices, Telephone Number, Commission File Number, IRS Employer Identification Number

ALLIANT ENERGY CORPORATION

(a Wisconsin Corporation)

4902 N. Biltmore Lane

Madison, Wisconsin 53718

Telephone (608) 458-3311

Commission File Number - 1-9894

IRS Employer Identification Number - 39-1380265

INTERSTATE POWER & LIGHT COMPANY

(an Iowa corporation)

Alliant Energy Tower

Cedar Rapids, Iowa 52401

Telephone (319) 786-4411

Commission File Number - 1-4117

IRS Employer Identification Number - 42-0331370

WISCONSIN POWER & LIGHT COMPANY

(a Wisconsin corporation)

4902 N. Biltmore Lane

Madison, Wisconsin 53718

Telephone (608) 458-3311

Commission File Number - 0-337

IRS Employer Identification Number - 39-0714890

This combined Form 10-Q is separately filed by Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company. Information contained in the Form 10-Q relating to Interstate Power and Light Company and Wisconsin Power and Light Company is filed by each such registrant on its own behalf. Each of Interstate Power and Light Company and Wisconsin Power and Light Company makes no representation as to information relating to registrants other than itself.

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

Alliant Energy Corporation, Common Stock, $0.01 Par Value, Trading Symbol LNT, Nasdaq Global Select Market

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.

Alliant Energy Corporation - Yes ☒ No ☐

Interstate Power and Light Company - Yes ☒ No ☐

Wisconsin Power and Light Company - 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 (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Alliant Energy Corporation - Yes ☒ No ☐

Interstate Power and Light Company - Yes ☒ No ☐

Wisconsin Power and Light Company - 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.

Alliant Energy Corporation - Large Accelerated Filer ☒ Accelerated Filer ☐ Non-accelerated Filer ☐ Smaller Reporting Company ☐ Emerging Growth Company ☐

Interstate Power and Light Company - Large Accelerated Filer ☐ Accelerated Filer ☐ Non-accelerated Filer ☒ Smaller Reporting Company ☐ Emerging Growth Company ☐

Wisconsin Power and Light Company - 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.

Alliant Energy Corporation ☐

Interstate Power and Light Company ☐

Wisconsin Power and Light Company ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

Alliant Energy Corporation - Yes ☐ No ☒

Interstate Power and Light Company - Yes ☐ No ☒

Wisconsin Power and Light Company - Yes ☐ No ☒

Number of shares outstanding of each class of common stock as of March 31, 2024:

Alliant Energy Corporation, Common Stock, $0.01 par value, 256,379,032 shares outstanding

Interstate Power and Light Company, Common Stock, $2.50 par value, 13,370,788 shares outstanding (all outstanding shares are owned beneficially and of record by Alliant Energy Corporation)

Wisconsin Power and Light Company, Common Stock, $5 par value, 13,236,601 shares outstanding (all outstanding shares are owned beneficially and of record by Alliant Energy Corporation)

Table of Contents

TABLE OF CONTENTS

			Page
Definitions			1
Forward-looking Statements			1
Part I. Financial Information			3
Item 1. Condensed Consolidated Financial Statements (Unaudited)			3
Alliant Energy Corporation			3
Interstate Power and Light Company			6
Wisconsin Power and Light Company			9
Combined Notes to Condensed Consolidated Financial Statements			12
1. Summary of Significant Accounting Policies			12
2. Regulatory Matters			12
3. Property, Plant and Equipment			13
4. Receivables			13
5. Investments			13
6. Common Equity			13
7. Debt			15
8. Revenues			15
9. Income Taxes			16
10. Benefit Plans			16
11. Derivative Instruments			17
12. Fair Value Measurements			18
13. Commitments and Contingencies			20
14. Segments of Business			22
15. Related Parties			22
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations			23
Item 3. Quantitative and Qualitative Disclosures About Market Risk			29
Item 4. Controls and Procedures			29
Part II. Other Information			29
Item 1. Legal Proceedings			29
Item 1A. Risk Factors			29
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds			29
Item 5. Other Information			30
Item 6. Exhibits			30
Signatures			30

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DEFINITIONS

The following abbreviations or acronyms used in this report are defined below:

Abbreviation or Acronym			Definition			Abbreviation or Acronym			Definition
2023 Form 10-K			Combined Annual Report on Form 10-K filed by Alliant Energy, IPL and WPL for the year ended Dec. 31, 2023			IUB			Iowa Utilities Board
AEF			Alliant Energy Finance, LLC			MDA			Management’s Discussion and Analysis of Financial Condition and Results of Operations
AFUDC			Allowance for funds used during construction			MISO			Midcontinent Independent System Operator, Inc.
Alliant Energy			Alliant Energy Corporation			MW			Megawatt
ATC			American Transmission Company LLC			MWh			Megawatt-hour
ATC Holdings			Interest in American Transmission Company LLC and ATC Holdco LLC			N/A			Not applicable
Corporate Services			Alliant Energy Corporate Services, Inc.			Note(s)			Combined Notes to Condensed Consolidated Financial Statements
Dth			Dekatherm			OPEB			Other postretirement benefits
EGU			Electric generating unit			PPA			Purchased power agreement
EPA			U.S. Environmental Protection Agency			PSCW			Public Service Commission of Wisconsin
EPS			Earnings per weighted average common share			SEC			Securities and Exchange Commission
Financial Statements			Condensed Consolidated Financial Statements			U.S.			United States of America
FTR			Financial transmission right			West Riverside			West Riverside Energy Center and Solar Facility
GAAP			U.S. generally accepted accounting principles			Whiting Petroleum			Whiting Petroleum Corporation
IPL			Interstate Power and Light Company			WPL			Wisconsin Power and Light Company

FORWARD-LOOKING STATEMENTS

Statements contained in this report that are not of historical fact are forward-looking statements intended to qualify for the safe harbors from liability established by the Private Securities Litigation Reform Act of 1995. These forward-looking statements can be identified as such because the statements include words such as “may,” “believe,” “expect,” “anticipate,” “plan,” “project,” “will,” “projections,” “estimate,” or other words of similar import. Similarly, statements that describe future financial performance or plans or strategies are forward-looking statements. Such forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those expressed in, or implied by, such statements. Some, but not all, of the risks and uncertainties of Alliant Energy, IPL and WPL that could materially affect actual results include:

• the direct or indirect effects resulting from cybersecurity incidents or attacks on Alliant Energy, IPL, WPL, or their suppliers, contractors and partners, or responses to such incidents;

• the impact of customer- and third party-owned generation, including alternative electric suppliers, in IPL’s and WPL’s service territories on system reliability, operating expenses and customers’ demand for electricity;

• economic conditions and the impact of business or facility closures in IPL’s and WPL’s service territories;

• the impact of energy efficiency, franchise retention and customer disconnects on sales volumes and operating income;

• the impact that price changes may have on IPL’s and WPL’s customers’ demand for electric, gas and steam services and their ability to pay their bills;

• changes in the price of delivered natural gas, transmission, purchased electricity and delivered coal, particularly during elevated market prices, and any resulting changes to counterparty credit risk, due to shifts in supply and demand caused by market conditions, regulations and MISO’s seasonal resource adequacy process;

• IPL’s and WPL’s ability to obtain adequate and timely rate relief to allow for, among other things, the recovery of and/or the return on costs, including fuel costs, operating costs, transmission costs, capacity costs, deferred expenditures, deferred tax assets, tax expense, interest expense, capital expenditures, and remaining costs related to EGUs that may be permanently closed and certain other retired assets, decreases in sales volumes, earning their authorized rates of return, payments to their parent of expected levels of dividends, and the impact of rate design on current and potential customers’ demand for energy in their service territories;

• weather effects on utility sales volumes and operations;

• the ability to obtain deferral treatment for the recovery of and a return on prudently incurred costs in between rate reviews;

• the ability to obtain regulatory approval for construction projects with acceptable conditions;

• the ability to complete construction of renewable generation and storage projects by planned in-service dates and within the cost targets set by regulators due to cost increases of and access to materials, equipment and commodities, which could result from tariffs, duties or other assessments, such as any additional tariffs resulting from U.S. Department of Commerce investigations into and any decisions made regarding the sourcing of solar project materials and equipment from certain countries, labor issues or supply shortages, the ability to successfully resolve warranty issues or contract disputes, the ability to achieve the expected level of tax benefits based on tax guidelines, project costs and the level of electricity output generated by qualifying generating facilities, and the ability to efficiently utilize the renewable generation and storage project tax benefits for the benefit of customers;

• WPL’s ability to obtain rate relief to allow for the return on costs of solar generation projects that exceed initial cost estimates;

• the impacts of changes in the tax code, including tax rates, minimum tax rates, adjustments made to deferred tax assets and liabilities, and changes impacting the availability of and ability to transfer renewable tax credits;

• the ability to utilize tax credits generated to date, and those that may be generated in the future, before they expire, as well as the ability to transfer tax credits that may be generated in the future at adequate pricing;

• disruptions to ongoing operations and the supply of materials, services, equipment and commodities needed to construct solar generation, battery storage and electric and gas distribution projects, which may result from geopolitical issues, supplier manufacturing constraints, regulatory requirements, labor issues or transportation issues, and thus affect the ability to meet capacity requirements and result in increased capacity expense;

• inflation and higher interest rates;

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• the future development of technologies related to electrification, and the ability to reliably store and manage electricity;

• federal and state regulatory or governmental actions, including the impact of legislation, and regulatory agency orders and changes in public policy;

• employee workforce factors, including the ability to hire and retain employees with specialized skills, impacts from employee retirements, changes in key executives, ability to create desired corporate culture, collective bargaining agreements and negotiations, work stoppages or restructurings;

• disruptions in the supply and delivery of natural gas, purchased electricity and coal;

• changes to the creditworthiness of, or performance of obligations by, counterparties with which Alliant Energy, IPL and WPL have contractual arrangements, including participants in the energy markets and fuel suppliers and transporters;

• the impact of penalties or third-party claims related to, or in connection with, a failure to maintain the security of personally identifiable information, including associated costs to notify affected persons and to mitigate their information security concerns;

• impacts that terrorist attacks may have on Alliant Energy’s, IPL’s and WPL’s operations and recovery of costs associated with restoration activities, or on the operations of Alliant Energy’s investments;

• any material post-closing payments related to any past asset divestitures, including the transfer of renewable tax credits and the sale of Whiting Petroleum, which could result from, among other things, indemnification agreements, warranties, guarantees or litigation;

• continued access to the capital markets on competitive terms and rates, and the actions of credit rating agencies;

• changes to MISO’s resource adequacy process establishing capacity planning reserve margin and capacity accreditation requirements that may impact how and when new and existing generating facilities, including IPL’s and WPL’s additional solar generation, may be accredited with energy capacity, and may require IPL and WPL to adjust their current resource plans, to add resources to meet the requirements of MISO’s process, or procure capacity in the market whereby such costs might not be recovered in rates;

• issues associated with environmental remediation and environmental compliance, including compliance with all environmental and emissions permits and future changes in environmental laws and regulations, including the Coal Combustion Residuals Rule, Cross-State Air Pollution Rule and federal, state or local regulations for greenhouse gases emissions reductions from new and existing fossil-fueled EGUs under the Clean Air Act, and litigation associated with environmental requirements;

• increased pressure from customers, investors and other stakeholders to more rapidly reduce greenhouse gases emissions;

• the ability to defend against environmental claims brought by state and federal agencies, such as the EPA and state natural resources agencies, or third parties, such as the Sierra Club, and the impact on operating expenses of defending and resolving such claims;

• the direct or indirect effects resulting from breakdown or failure of equipment in the operation of electric and gas distribution systems, such as mechanical problems and explosions or fires, and compliance with electric and gas transmission and distribution safety regulations, including regulations promulgated by the Pipeline and Hazardous Materials Safety Administration;

• issues related to the availability and operations of EGUs, including start-up risks, breakdown or failure of equipment, availability of warranty coverage and successful resolution of warranty issues or contract disputes for equipment breakdowns or failures, performance below expected or contracted levels of output or efficiency, operator error, employee safety, transmission constraints, compliance with mandatory reliability standards and risks related to recovery of resulting incremental operating, fuel-related and capital costs through rates;

• impacts that excessive heat, excessive cold, storms, wildfires, or natural disasters may have on Alliant Energy’s, IPL’s and WPL’s operations and construction activities, and recovery of costs associated with restoration activities, or on the operations of Alliant Energy’s investments;

• Alliant Energy’s ability to sustain its dividend payout ratio goal;

• changes to costs of providing benefits and related funding requirements of pension and OPEB plans due to the market value of the assets that fund the plans, economic conditions, financial market performance, interest rates, timing and form of benefits payments, life expectancies and demographics;

• material changes in employee-related benefit and compensation costs, including settlement losses related to pension plans;

• risks associated with operation and ownership of non-utility holdings;

• changes in technology that alter the channels through which customers buy or utilize Alliant Energy’s, IPL’s or WPL’s products and services;

• impacts on equity income from unconsolidated investments from changes in valuations of the assets held, as well as potential changes to ATC’s authorized return on equity;

• impacts of IPL’s future tax benefits from Iowa rate-making practices, including deductions for repairs expenditures, allocation of mixed service costs and state depreciation, and recoverability of the associated regulatory assets from customers, when the differences reverse in future periods;

• current or future litigation, regulatory investigations, proceedings or inquiries;

• reputational damage from negative publicity, protests, fines, penalties and other negative consequences resulting in regulatory and/or legal actions;

• the direct or indirect effects resulting from pandemics;

• the effect of accounting standards issued periodically by standard-setting bodies;

• the ability to successfully complete tax audits and changes in tax accounting methods with no material impact on earnings and cash flows; and

• other factors listed in MDA and Risk Factors in Item 1A in the 2023 Form 10-K.

Alliant Energy, IPL and WPL each assume no obligation, and disclaim any duty, to update the forward-looking statements in this report, except as required by law.

Available Information. Alliant Energy routinely posts important information on its website and considers the Investors section of its website, www.alliantenergy.com/investors, a channel of distribution for material information. Information contained on Alliant Energy’s website is not incorporated herein by reference.

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PART I. FINANCIAL INFORMATION

ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

			For the Three Months
			Ended March 31,
			2024						2023
			(in millions, except per share amounts)
Revenues:
Electric utility			$791						$768
Gas utility			205						276
Other utility			13						11
Non-utility			22						22
Total revenues			1,031						1,077
Operating expenses:
Electric production fuel and purchased power			163						157
Electric transmission service			152						146
Cost of gas sold			114						181
Other operation and maintenance			160						174
Depreciation and amortization			189						166
Taxes other than income taxes			31						31
Total operating expenses			809						855
Operating income			222						222
Other (income) and deductions:
Interest expense			107						94
Equity income from unconsolidated investments, net			(15)						(17)
Allowance for funds used during construction			(19)						(19)
Other			1						3
Total other (income) and deductions			74						61
Income before income taxes			148						161
Income tax benefit			(10)						(2)
Net income attributable to Alliant Energy common shareowners			$158						$163
Weighted average number of common shares outstanding:
Basic			256.2						251.2
Diluted			256.5						251.4
Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted)			$0.62						$0.65

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

			March 31, 2024						December 31, 2023
			(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents			$32						$62
Accounts receivable, less allowance for expected credit losses			426						475
Production fuel, at weighted average cost			60						62
Gas stored underground, at weighted average cost			52						79
Materials and supplies, at weighted average cost			208						202
Regulatory assets			218						232
Other			112						160
Total current assets			1,108						1,272
Property, plant and equipment, net			17,354						17,157
Investments:
ATC Holdings			392						386
Other			219						216
Total investments			611						602
Other assets:
Regulatory assets			2,002						2,029
Deferred charges and other			173						177
Total other assets			2,175						2,206
Total assets			$21,248						$21,237

LIABILITIES AND EQUITY
Current liabilities:
Current maturities of long-term debt			$809						$809
Commercial paper			334						475
Accounts payable			438						611
Regulatory liabilities			100						107
Other			303

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This MDA includes information relating to Alliant Energy, and IPL and WPL (collectively, the Utilities), as well as ATC Holdings, AEF and Corporate Services. Where appropriate, information relating to a specific entity has been segregated and labeled as such. The following discussion and analysis should be read in conjunction with the Financial Statements and the Notes included in this report, as well as the financial statements, notes and MDA included in the 2023 Form 10-K. Unless otherwise noted, all “per share” references in MDA refer to earnings per diluted share.

2024 HIGHLIGHTS

Key highlights since the filing of the 2023 Form 10-K include the following:

Customer Investments:

• In March 2024, IPL completed construction of the Duane Arnold solar facility (50 MW in Linn County, Iowa).

• In March 2024 and April 2024, FERC and the PSCW, respectively, approved the sales of WPL’s partial ownership interests in West Riverside to WEC Energy Group, Inc. (100 MW) and Madison Gas and Electric Company (25 MW). These sales are currently expected to occur in June 2024.

• In April 2024, WPL received orders from the PSCW authorizing WPL to construct improvements at the natural gas-fired Neenah Energy Facility and Sheboygan Falls Energy Facility, which would increase the capacity and efficiency of the EGUs.

• In April 2024, IPL and WPL entered into agreements to transfer a portion of the renewable tax credits generated in 2024 and 2025 from certain wind, solar and battery storage facilities to other corporate taxpayers in exchange for cash.

Rate Matters:

• Refer to Note 3 for discussion of WPL’s March 2024 filing for judicial review of PSCW orders related to the recovery and deferral of the return on incremental solar generation construction costs in 2024 and 2025.

Environmental Matters:

• In April 2024, the EPA issued the final Section 111(d) rule for certain fossil-fueled EGUs and repealed the Affordable Clean Energy rule. The final Section 111(d) rule requires states to implement plans to reduce carbon dioxide emissions through various Best System of Emission Reduction measures at affected sources, including retirement, enforceable limits on operational capacity, co-firing with low-GHG fuels, or carbon capture and storage technology. State plans are subject to EPA approval, and must be submitted within 24 months of the final rule’s effective date, which has not yet been determined. The final rule’s compliance requirements will be phased in beginning in 2030 and covers fossil-fueled EGUs that utilize steam boilers to generate electricity, including IPL’s coal-fired Ottumwa Generating Station, George Neal Generating Station, Prairie Creek Generating Station Unit 3 and Louisa Generating Station, and IPL’s natural gas-fired Burlington Generating Station and Prairie Creek Generating Station Unit 4. The final rule does not apply to EGUs that are retired by January 2032 and is not currently expected to impact WPL’s coal-fired Columbia Energy Center or Edgewater Generating Station given current plans to retire these EGUs prior to this deadline. In addition, the final rule does not impact existing natural gas-fired combustion turbines, including IPL’s Marshalltown Generating Station and Emery Generating Station, and WPL’s Riverside Energy Center and West Riverside Energy Center; however, these EGUs could be subject to future Section 111(d) rules to reduce carbon dioxide emissions from existing combustion turbines. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters, including resolution of ongoing litigation that has been suspended while the EPA revised its regulations.

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• In April 2024, the EPA issued final revised standards under Section 111(b), which establishes carbon dioxide emissions limits from certain new and reconstructed fossil-fueled EGU combustion turbines that commenced operation after May 23, 2023 with a capacity greater than 25 MW. The final revised standards do not apply to IPL’s Marshalltown Generating Station or WPL’s West Riverside Energy Center, which commenced operation prior to the applicability date of the final revised standards. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these revised standards, including resolution of ongoing litigation that has been suspended while the EPA revised its regulations.

• In April 2024, the EPA issued a final rule that revises discharge limits for specific categories of wastewater from existing coal-fired EGUs. The new limitations will be implemented in each facility’s wastewater discharge permits issued by state agencies and become effective as soon as possible but no later than December 31, 2029. Alliant Energy, IPL and WPL are currently evaluating the final rule and are unable to predict with certainty future compliance impacts.

• In April 2024, the EPA issued revisions to the Coal Combustion Residuals Rule, which significantly expand the scope of regulation to include coal ash ponds at sites that no longer produce electricity and inactive landfills, including some IPL and WPL facilities. Alliant Energy, IPL and WPL are currently evaluating the revised Coal Combustion Residuals Rule and are unable to predict with certainty the future outcome or impact of these updates.

Legislative Matters:

• In May 2024, the Major Economic Growth Attraction program was enacted in Iowa, which offers various tax incentives for up to two qualified businesses for certain large-scale projects with capital investments greater than $1 billion constructed on certified sites greater than 250 acres in Iowa. The most significant provision of this program for Alliant Energy encourages economic development in IPL’s service territory. Alliant Energy has various development-ready sites throughout Iowa, including the 1,300-acre Big Cedar Industrial Center Mega-site in Cedar Rapids, Iowa, and the 465-acre Prairie View Industrial Center Super Park in Ames, Iowa.

• In May 2024, legislation was enacted in Iowa related to the advance rate-making principles for certain investments in Iowa. The most signification provisions of this legislation for Alliant Energy would allow IPL to include electric storage and nuclear-fired generation projects in the advance rate-making principles request process prior to making these investments in Iowa, and require IPL to obtain a certificate of public convenience, use and necessity (GCU Certificate) from the IUB in order to construct electric storage projects.

RESULTS OF OPERATIONS

Financial Results Overview - The table below includes EPS for Utilities and Corporate Services, ATC Holdings, and Non-utility and Parent, which are non-GAAP financial measures. Alliant Energy believes these non-GAAP financial measures are useful to investors because they facilitate an understanding of segment performance and trends, and provide additional information about Alliant Energy’s operations on a basis consistent with the measures that management uses to manage its operations and evaluate its performance. Alliant Energy’s net income and EPS attributable to Alliant Energy common shareowners for the three months ended March 31 were as follows (dollars in millions, except per share amounts):

			2024												2023
			Income (Loss)						EPS						Income (Loss)						EPS
Utilities and Corporate Services			$159						$0.62						$163						$0.65
ATC Holdings			9						0.04						9						0.04
Non-utility and Parent			(10)						(0.04)						(9)						(0.04)
Alliant Energy Consolidated			$158						$0.62						$163						$0.65

Alliant Energy’s Utilities and Corporate Services net income decreased by $4 million for the three-month period, primarily due to lower retail electric and gas sales due to impacts of warmer than normal temperatures during the three months ended March 31, 2024, and higher financing and depreciation expenses. These items were partially offset by higher revenue requirements from WPL’s capital investments.

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Net Income Variances - The following items contributed to increased (decreased) net income for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):

			Alliant Energy						IPL						WPL
Revenues:
Changes in electric utility (Refer to details below)			$23						$4						$19
Changes in gas utility (Refer to details below)			(71)						(42)						(29)
Changes in other utility			2						2						—
Changes in total revenues			(46)						(36)						(10)
Operating expenses:
Changes in electric production fuel and purchased power (Refer to details below)			(6)						(20)						13
Changes in electric transmission service			(6)						1						(7)
Changes in cost of gas sold (Refer to details below)			67						35						33
Changes in other operation and maintenance (Refer to details below)			14						9						3
Changes in depreciation and amortization (Higher primarily due to WPL’s solar generation placed in service in 2023, as well as WPL’s amortization of liquidated damages related to West Riverside procurement contracts, which resulted in reductions to depreciation and amortization expenses in the first quarter of 2023)			(23)						—						(22)
Changes in total operating expenses			46						25						20
Changes in operating income			—						(11)						10
Other income and deductions:
Changes in interest expense (Higher primarily due to financings completed in 2024 and 2023)			(13)						(5)						(5)
Changes in equity income from unconsolidated investments, net (Refer to Note 5 for details)			(2)						—						—
Changes in AFUDC (Primarily due to changes in levels of CWIP balances related to solar generation and battery storage)			—						7						(7)
Changes in Other			2						1						—
Changes in total other income and deductions			(13)						3						(12)
Changes in income before income taxes			(13)						(8)						(2)
Changes in income taxes (Refer to Note 9 for details)			8						(1)						6
Changes in net income			($5)						($9)						$4

Electric and Gas Revenues and Sales Summary - Electric and gas revenues (in millions), and MWh and Dth sales (in thousands), for the three months ended March 31 were as follows:

Alliant Energy			Electric																								Gas
			Revenues												MWhs Sold												Revenues												Dths Sold
			2024						2023						2024						2023						2024						2023						2024						2023
Retail			$706						$686						5,989						6,201						$192						$262						20,117						22,310
Sales for resale:
Wholesale			47						46						679						698						N/A						N/A						N/A						N/A
Bulk power and other			21						23						1,670						1,243						N/A						N/A						N/A						N/A
Transportation/Other			17						13						15						15						13						14						33,908						32,614
			$791						$768						8,353						8,157						$205						$276						54,025						54,924

IPL			Electric																								Gas
			Revenues												MWhs Sold												Revenues												Dths Sold
			2024						2023						2024						2023						2024						2023						2024						2023
Retail			$376						$362						3,365						3,544						$101						$141						10,205						11,459
Sales for resale:
Wholesale			13						12						182						187						N/A						N/A						N/A						N/A
Bulk power and other			(3)						7						324						496						N/A						N/A						N/A						N/A
Transportation/Other			6						7						8						8						7						9						11,695						12,035
			$392						$388						3,879						4,235						$108						$150						21,900						23,494

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WPL			Electric																								Gas
			Revenues												MWhs Sold												Revenues												Dths Sold
			2024						2023						2024						2023						2024						2023						2024						2023
Retail			$330						$324						2,624						2,657						$91						$121						9,912						10,851
Sales for resale:
Wholesale			34						34						497						511						N/A						N/A						N/A						N/A
Bulk power and other			24						16						1,346						747						N/A						N/A						N/A						N/A
Transportation/Other			11						6						7						7						6						5						22,213						20,579
			$399						$380						4,474						3,922						$97						$126						32,125						31,430

Sales Trends and Temperatures - Alliant Energy’s retail electric sales volumes decreased 3% for the three months ended March 31, 2024 compared to the same period in 2023, primarily due to changes in sales volumes to industrial customers due to standby service customers that can use other generation and changes in temperatures, partially offset by an additional day of sales due to leap year in 2024. Alliant Energy’s retail gas sales volumes decreased 10% for the three months ended March 31, 2024 compared to the same period in 2023, primarily due to changes in temperatures, partially offset by an additional day of sales due to leap year in 2024.

Estimated decreases to operating income from the impacts of temperatures for the three months ended March 31 were as follows (in millions):

			Electric																		Gas
			2024						2023						Change																								2024						2023						Change
IPL			($9)						($4)						($5)																								($6)						($3)						($3)
WPL			(10)						(5)						(5)																								(5)						(3)						(2)
Total Alliant Energy			($19)						($9)						($10)																								($11)						($6)						($5)

Electric Sales for Resale - Bulk Power and Other - Bulk power and other volume changes were due to changes in sales in the wholesale energy markets operated by MISO. These changes are impacted by several factors, including the availability and dispatch of Alliant Energy’s EGUs and electricity demand within these wholesale energy markets. Changes in bulk power and other revenues were largely offset by changes in fuel-related costs, and therefore did not have a significant impact on operating income.

Gas Transportation/Other - Gas transportation/other sales volume changes were largely due to changes in the gas volumes supplied to Alliant Energy’s natural gas-fired EGUs caused by the availability and dispatch of such EGUs.

Electric Utility Revenue Variances - The following items contributed to increased (decreased) electric utility revenues for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):

			Alliant Energy						IPL						WPL
Higher revenue requirements at WPL (a)			$38						$—						$38
Estimated changes in sales volumes caused by temperatures			(10)						(5)						(5)
Higher (lower) sales for resale bulk power and other revenues			(2)						(10)						8
Higher (lower) revenues due to changes in retail electric fuel-related costs (Refer to Electric Production Fuel and Purchased Power Expenses Variances below) (a)			(1)						26						(27)
Other			(2)						(7)						5
			$23						$4						$19

(a)In December 2023, the PSCW issued an order authorizing an annual base rate increase of $49 million for WPL’s retail electric customers, covering the 2024 forward-looking Test Period, which reflects revenue requirement impacts of increasing electric rate base and lower forecasted fuel-related expenses.

Gas Utility Revenue Variances - The following items contributed to increased (decreased) gas utility revenues for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):

			Alliant Energy						IPL						WPL
Lower revenues due to changes in gas costs (Refer to Cost of Gas Sold Expense Variances below)			($67)						($35)						($33)
Estimated changes in sales volumes caused by temperatures			(5)						(3)						(2)
Higher revenue requirements at WPL (a)			5						—						5
Other			(4)						(4)						1
			($71)						($42)						($29)

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(a)In December 2023, the PSCW issued an order authorizing an annual base rate increase of $13 million for WPL’s retail gas customers, covering the 2024 forward-looking Test Period, which reflects revenue requirement impacts of increasing gas rate base.

Electric Production Fuel and Purchased Power Expenses Variances - The following items contributed to (increased) decreased electric production fuel and purchased power expenses for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):

			Alliant Energy						IPL						WPL
Lower electric production fuel costs (a)			$53						$38						$15
Changes in regulatory recovery of retail electric fuel-related costs			(31)						(38)						7
Higher purchased power expense (b)			(27)						(20)						(7)
Other			(1)						—						(2)
			($6)						($20)						$13

(a)Electric production fuel costs decreased primarily due to lower natural gas prices in the first quarter of 2024 compared to the same period in 2023 and lower natural gas volumes due to lower dispatch of IPL’s natural gas-fired EGUs in 2024, partially offset by higher coal volumes due to higher dispatch of WPL’s coal-fired EGUs in 2024.

(b)Purchased power expense increased primarily due to higher prices for electricity purchased by IPL and WPL.

Cost of Gas Sold Expense Variances - The following items contributed to (increased) decreased cost of gas sold expense for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):

			Alliant Energy						IPL						WPL
Lower natural gas prices and lower retail gas volumes primarily due to changes in temperatures			$75						$50						$25
Changes in the regulatory recovery of gas costs			(6)						(14)						8
Other			(2)						(1)						—
			$67						$35						$33

Other Operation and Maintenance Expenses Variances - The following items contributed to (increased) decreased other operation and maintenance expenses for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):

			Alliant Energy						IPL						WPL
Lower generation and energy delivery expenses			$8						$1						$7
Lower energy efficiency expense at IPL (mostly offset by higher revenues)			7						7						—
Other			(1)						1						(4)
			$14						$9						$3

LIQUIDITY AND CAPITAL RESOURCES

The liquidity and capital resources summary included in the 2023 Form 10-K has not changed materially, except as described below.

Liquidity Position - At March 31, 2024, Alliant Energy had $32 million of cash and cash equivalents, $666 million ($166 million at the parent company, $200 million at IPL and $300 million at WPL) of available capacity under the single revolving credit facility and $92 million of available capacity at IPL under its sales of accounts receivable program.

Capital Structure - Capital structures at March 31, 2024 were as follows (Long-term Debt (including current maturities) (LD); Short-term Debt (SD); Common Equity (CE)):

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Cash Flows - Selected information from the cash flows statements was as follows (in millions):

			Alliant Energy												IPL												WPL
			2024						2023						2024						2023						2024						2023
Cash, cash equivalents and restricted cash, January 1			$63						$24						$53						$15						$7						$5
Cash flows from (used for):
Operating activities			307						188						76						24						241						185
Investing activities			(353)						(263)						(107)						70						(213)						(295)
Financing activities			18						212						(10)						(74)						(24)						191
Net increase (decrease)			(28)						137						(41)						20						4						81
Cash, cash equivalents and restricted cash, March 31			$35						$161						$12						$35						$11						$86

Operating Activities - The following items contributed to increased (decreased) operating activity cash flows for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):

			Alliant Energy						IPL						WPL
Higher collections from WPL’s retail electric and gas base rate increases			$43						$—						$43
Changes in the sales of accounts receivable at IPL			18						18						—
Decreased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales			(15)						(8)						(7)
Other (primarily due to other changes in working capital)			73						42						20
			$119						$52						$56

Investing Activities - The following items contributed to increased (decreased) investing activity cash flows for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):

			Alliant Energy						IPL						WPL
(Higher) lower utility construction and acquisition expenditures (a)			($61)						($152)						$91
Proceeds from sale of partial ownership interest in West Riverside in 2023			(25)						—						(25)
Changes in the amount of cash receipts on sold receivables			(18)						(18)						—
Other			14						(7)						16
			($90)						($177)						$82

(a)Largely due to higher expenditures for IPL’s solar generation and WPL’s battery storage, partially offset by lower expenditures for WPL’s solar generation.

Financing Activities - The following items contributed to increased (decreased) financing activity cash flows for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):

			Alliant Energy						IPL						WPL
Higher payments to retire long-term debt			($300)						$—						$—
Lower net proceeds from issuance of long-term debt			(265)						—						—
(Higher) lower common stock dividends			(10)						20						(3)
Higher (lower) capital contributions from IPL’s and WPL’s parent company, Alliant Energy			—						50						(125)
Net changes in the amount of commercial paper and other short-term borrowings outstanding			391						—						(88)
Other			(10)						(6)						1
			($194)						$64						($215)

Common Stock Issuances - Refer to Note 6 for discussion of common stock issuances by Alliant Energy in 2024.

Long-term Debt - Refer to Note 7(b) for discussion of various issuances and/or retirements of long-term debt by AEF and WPL in 2024.

Impact of Credit Ratings on Liquidity and Collateral Obligations -

Ratings Triggers - In March 2024, Standard & Poor’s Ratings Services changed Alliant Energy’s and IPL’s outlooks from stable to negative. These outlook changes are not expected to have a material impact on Alliant Energy’s and IPL’s liquidity or collateral obligations.

Off-Balance Sheet Arrangements and Certain Financial Commitments - A summary of Alliant Energy’s and IPL’s off-balance sheet arrangements and Alliant Energy’s, IPL’s and WPL’s contractual obligations is included in the 2023 Form 10-K and has not changed materially from the items reported in the 2023 Form 10-K, except for the items described in Notes 4, 7 and 13.

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OTHER MATTERS

Critical Accounting Estimates - The summary of critical accounting estimates included in the 2023 Form 10-K has not changed materially, except as described below.

Long-Lived Assets -

Regulated Operations -

Solar Generation Projects Recently Completed or Under Construction - Alliant Energy and WPL currently expect construction costs associated with WPL’s approximately 1,100 MW of new solar generation will exceed the construction cost estimates previously approved by the PSCW by approximately $180 million. In February 2024, the PSCW issued an order approving deferral of the incremental solar generation construction costs. The PSCW’s order did not authorize a deferral for the return on such costs. In March 2024, WPL filed for judicial review of the PSCW’s retail electric rate review order (2024/2025 forward-looking Test Period) and solar generation construction cost deferral order related to the recovery and deferral of the return on the incremental solar generation construction costs in 2024 and 2025. Alliant Energy and WPL concluded that there was not a probable disallowance of anticipated higher rate base amounts as of March 31, 2024 given construction costs were reasonably and prudently incurred.