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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM 10-K
    ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the fiscal year ended December 31, 2023

or

    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the transition period from                    to                    

alliantenergylogo.jpg
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-K is separately filed by Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company. Information contained in the Form 10-K 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
Securities registered pursuant to Section 12(g) of the Act: None
Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.
Alliant Energy Corporation - Yes ☒ No ☐
Interstate Power and Light Company - Yes ☒ No ☐
Wisconsin Power and Light Company - Yes ☒ No ☐
Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.
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 (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 registrants were 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, accelerated filer, non-accelerated filer, smaller reporting company, or 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 has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (§ 15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.
Alliant Energy Corporation
Interstate Power and Light Company ☐
Wisconsin Power and Light Company ☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.
Alliant Energy Corporation
Interstate Power and Light Company
Wisconsin Power and Light Company
Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant's executive officers during the relevant recovery period pursuant to §240.10D-1(b).
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 ☒
The aggregate market value of the voting and non-voting common equity held by nonaffiliates as of June 30, 2023:
Alliant Energy Corporation - $13.2 billion
Interstate Power and Light Company - $0
Wisconsin Power and Light Company - $0
Number of shares outstanding of each class of common stock as of January 31, 2024:
Alliant Energy Corporation, Common Stock, $0.01 par value, 256,100,293 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)
DOCUMENTS INCORPORATED BY REFERENCE
Portions of the Proxy Statement relating to Alliant Energy Corporation’s 2024 Annual Meeting of Shareowners are, or will be upon filing with the Securities and Exchange Commission, incorporated by reference into Part III hereof.


TABLE OF CONTENTS
Page Number



DEFINITIONS
The following abbreviations or acronyms used in this report are defined below:
Abbreviation or AcronymDefinitionAbbreviation or AcronymDefinition
2024 Alliant Energy Proxy Statement
Alliant Energy’s Proxy Statement for the 2024 Annual Meeting of Shareowners
GAAPU.S. generally accepted accounting principles
AEFAlliant Energy Finance, LLCGHGGreenhouse gases
AFUDCAllowance for funds used during constructionIPLInterstate Power and Light Company
Alliant EnergyAlliant Energy CorporationIRSInternal Revenue Service
AROAsset retirement obligationITCITC Midwest LLC
ATCAmerican Transmission Company LLCIUBIowa Utilities Board
ATC HoldingsInterest in American Transmission Company LLC and ATC Holdco LLCKWhKilowatt-hour
ATIAE Transco Investments, LLCMDAManagement’s Discussion and Analysis of Financial Condition and Results of Operations
CACertificate of authorityMGPManufactured gas plant
CAAClean Air ActMISOMidcontinent Independent System Operator, Inc.
CCRCoal combustion residualsMWMegawatt
CO2Carbon dioxideMWhMegawatt-hour
Corporate ServicesAlliant Energy Corporate Services, Inc.N/ANot applicable
CPCNCertificate of Public Convenience and NecessityNote(s)Combined Notes to Consolidated Financial Statements
CSAPRCross-State Air Pollution RuleOIPAlliant Energy Omnibus Incentive Plan
CWIPConstruction work in progressOPEBOther postretirement benefits
DAECDuane Arnold Energy CenterPPAPurchased power agreement
DCPAlliant Energy Deferred Compensation PlanPSCWPublic Service Commission of Wisconsin
DthDekathermReceivables AgreementReceivables Purchase and Sale Agreement
EGUElectric generating unitSECSecurities and Exchange Commission
EPAU.S. Environmental Protection AgencyU.S.United States of America
EPSEarnings per weighted average common shareVEBAVoluntary Employees’ Beneficiary Association
FERCFederal Energy Regulatory CommissionVIEVariable interest entity
Financial StatementsConsolidated Financial StatementsWest RiversideWest Riverside Energy Center and Solar Facility
FTRFinancial transmission rightWhiting PetroleumWhiting Petroleum Corporation
Fuel-relatedElectric production fuel and purchased powerWPLWisconsin 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 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, and the payments to their parent of expected levels of dividends;
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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 adequate and timely rate relief to allow for the recovery of and/or 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, 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;
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;
weather effects on utility sales volumes and operations;
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 CCR rule, CSAPR and federal, state or local regulations for GHG emissions reductions from new and existing fossil-fueled EGUs under the CAA, and litigation associated with environmental requirements;
increased pressure from customers, investors and other stakeholders to more rapidly reduce GHG 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;
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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 Item 1A Risk Factors.

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.

WEBSITE ACCESS TO REPORTS
Alliant Energy, IPL and WPL make their periodic and current reports, and amendments to those reports, available, free of charge, on Alliant Energy’s website at www.alliantenergy.com/investors on the same day as such material is electronically filed with, or furnished to, the SEC. Alliant Energy, IPL and WPL are not including the information contained on Alliant Energy’s website as a part of, or incorporating it by reference into, this report.

PART I

This report includes information relating to Alliant Energy, IPL and WPL (as well as AEF and Corporate Services). Where appropriate, information relating to a specific entity has been segregated and labeled as such. Unless otherwise noted, the information herein excludes discontinued operations for all periods presented. The terms “we,” “our” and “us” used in this report refer collectively to Alliant Energy, IPL and WPL.

ITEM 1. BUSINESS

A. GENERAL
Alliant Energy maintains its principal executive offices in Madison, Wisconsin. Alliant Energy operates as a regulated investor-owned public utility holding company, and its purpose-driven strategy is to serve its customers and build stronger communities. Alliant Energy’s primary focus is to provide regulated electric and natural gas service to approximately 1,000,000 electric and approximately 425,000 natural gas customers in the Midwest through its two public utility subsidiaries, IPL and WPL. The primary first tier wholly-owned subsidiaries of Alliant Energy are as follows:

1) IPL - is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Iowa. IPL provides utility services to incorporated communities as directed by the IUB and utilizes non-exclusive franchises, which cover the use of public right-of-ways for utility facilities in incorporated communities for a maximum term of 25 years. At December 31, 2023, IPL supplied electric and natural gas service to approximately 500,000 and 225,000 retail customers, respectively, in Iowa. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa. IPL is also engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa.

2) WPL - is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Wisconsin. WPL operates in municipalities pursuant to permits of indefinite duration and state statutes authorizing utility operation in areas annexed by a municipality. At December 31, 2023, WPL supplied electric and natural gas service to approximately 500,000 and 200,000 retail customers, respectively. WPL also sells electricity to wholesale customers in Wisconsin.
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3) CORPORATE SERVICES - provides administrative services to Alliant Energy, IPL, WPL and AEF.

4) AEF - Alliant Energy’s non-utility holdings are organized under AEF, which manages a portfolio of wholly-owned subsidiaries and additional holdings, including the following distinct platforms:

ATI - currently holds all of Alliant Energy’s interest in ATC Holdings. ATC Holdings is comprised of a 16% ownership interest in ATC and a 20% ownership interest in ATC Holdco LLC. ATC is an independent, for-profit, transmission-only company. ATC Holdco LLC holds an interest in Duke-American Transmission Company, LLC, a joint venture between Duke Energy Corporation and ATC, that owns electric transmission infrastructure in North America.

Corporate Venture Investments - includes various minority ownership interests in regional and national venture funds, including a global coalition of energy companies working together to help advance the transition towards a cleaner, more sustainable, and inclusive energy future, by identifying and researching innovative technologies and business models within the emerging energy economy.

Non-utility Wind Farm - includes a 50% cash equity ownership interest in a 225 MW non-utility wind farm located in Oklahoma.

Sheboygan Falls Energy Facility - is a 347 MW, simple-cycle, natural gas-fired EGU near Sheboygan Falls, Wisconsin, which is currently leased to WPL through 2039. Refer to Note 10 for additional information on WPL’s Sheboygan Falls Energy Facility lease.

Travero - is a diversified supply chain solutions company, including a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; wind turbine blade recycling services; and a rail-served warehouse in Iowa.

Development-ready Sites - includes various rail-served and ready-to-build manufacturing and industrial sites throughout Iowa and Wisconsin, with access to various airports, interstate freeways and Alliant Energy’s electric services.

B. INFORMATION RELATING TO ALLIANT ENERGY ON A CONSOLIDATED BASIS

1) HUMAN CAPITAL MANAGEMENT - Alliant Energy’s core purpose is to serve customers and build stronger communities. We constantly strive to attract, retain and develop a diverse and qualified workforce of high-performing employees, and create and foster an environment of inclusion and belonging for all employees.

Employees - At December 31, 2023, Alliant Energy, IPL and WPL had the following full- and part-time employees:
TotalNumber ofPercentage of Employees
Number ofBargaining UnitCovered by Collective
EmployeesEmployeesBargaining Agreements
Alliant Energy3,2811,755 53%
IPL1,116774 69%
WPL1,045868 83%

The majority of IPL’s bargaining unit employees are covered by the International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) collective bargaining agreement, which expires August 31, 2024. All of WPL’s bargaining unit employees are covered by the International Brotherhood of Electrical Workers Local 965 collective bargaining agreement, which expires May 31, 2026.

Safety - Safety is integral to our company’s culture. It is one of our Values - “Live safety. Everyone. Always. Our first priority is that nobody gets hurt.” Alliant Energy is committed to providing a safe environment for our employees, visitors, customers, contractors, vendors and the communities in which we live and work.

We focus on the proactive management of our safety performance. Our comprehensive behavioral safety-based program consists of leading indicators, lagging indicators and targeted focus programs. We utilize a formal safety management system to capture and track best practices, near misses, job site briefings, safety observations, safety conversations and any unsafe conditions. This system provides the insights needed to help drive a positive safety culture and help ensure compliance with safety rules, processes and procedures. We also use this system to broadly share lessons learned in support of shaping the mindsets and behaviors needed to help prevent similar events from occurring elsewhere. Collectively, this information is used to evaluate the safety performance of the executive and management teams related to their goals, and safety metrics are factored into short-term incentive awards.

We maintain executive and local safety leadership teams to establish our safety vision, strategy and priorities, and ensure education and recognition of employee actions that improve our safety culture. This leadership provides strong support for sustained growth of both employee and public safety programs and initiatives.
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Public safety is equally important as we interact with our customers to provide energy to their homes and businesses. We offer awareness campaigns, natural gas and electric public safety presentations, and free online resources and training programs and guidance to assist local emergency responders.

Total Rewards - Our market-competitive Total Rewards programs are designed to meet the varied and evolving needs of our employees. Through a variety of health, welfare and compensation programs, we offer employees choice and control, while supporting their financial, physical, and mental well-being. Tools and resources are provided to employees to help maintain and improve their health. Short- and long-term incentive plans are designed with a mix of operational and financial metrics that align employees with strategic corporate and social goals.

In addition to competitive salaries and wages, our Total Rewards programs include:
competitive short- and long-term incentive compensation;
a 401(k) savings plan with an employer match;
healthcare and insurance benefits, including medical, vision, dental, life, short-term disability, and long-term disability insurance;
health savings and flexible spending accounts;
enhanced offerings to support the well-being of employees and their families;
paid time off to use for vacation, personal time, sick time, holidays, bereavement, jury duty, military leave, parental leave, maternity leave, and adoption leave;
adoption assistance;
legal planning assistance;
tuition reimbursement;
Vacation Donation program; and
Volunteer Grants and Matching Gifts program.

Annually, Alliant Energy awards up to 25 scholarships to children of its current employees and eligible retirees who have achieved excellent records in high school who are pursuing a higher education. Scholarship award recipients may enroll in any accredited two- or four-year college, university or vocational-technical school in the U.S.

Diversity, Equity, Inclusion and Belonging (DEI&B) - A diverse, equitable and inclusive workplace where everyone feels like they belong is crucial for the success and retention of our employees, to attract future talent and to execute our purpose-driven strategy to serve our customers and build stronger communities. It is one of our Values - “Care for others: Together we create a workplace where people feel like they belong and can use their unique backgrounds, talents and perspectives to their fullest potential.” Alliant Energy is driven by DEI&B and believes the achievement of its strategic objectives can only be achieved with a focused and engaged workforce. Alliant Energy’s corporate officers group currently has approximately 44% gender diversity and 25% ethnic diversity.

Our efforts to create a diverse, equitable and inclusive workplace have focused on reducing bias, building diverse teams, and listening to and acting on employee feedback, and include:
learning opportunities for employees, such as inviting employees to participate in area diversity summits and supporting company-wide listening sessions, speakers and programs;
Employee Resource Groups that foster a diverse, equitable and inclusive workplace that supports employee well-being while promoting professional development and enhancing community relationships; and
a DEI&B Leadership Team that partners with the Human Resources department and hiring managers to attract more diverse applicants that represent the diversity of the communities we serve.

Our DEI&B initiatives also include a focus on building a diverse Board of Directors. We believe it is in our shareowners’ best interest to have a diverse Board representing a wide breadth of experiences and perspectives. Our Board currently has approximately 40% gender diversity and 20% ethnic diversity.

Our 2023 DEI&B accomplishments include:
received a perfect score on the Corporate Equality Index administered by the Human Rights Campaign Foundation to benchmark LGBTQ+ rights, policies and practices;
selected for the 2023 Bloomberg Gender-Equality Index; and
held our fourth annual Day of Understanding, with 88% voluntary company-wide participation, where leaders facilitated conversations around creating a culture of inclusion and belonging, helping to ensure employees are seen, heard and valued.

Alliant Energy’s short- and long-term incentive compensation plans include diversity metrics to drive leadership accountability for efforts to advance a diverse and inclusive culture.

Talent Development and Workforce Readiness - We support employees in the growth of their careers through several training opportunities and development programs. These include tuition reimbursement, and online, instructor-led and on-the-job learning formats, as well as leadership development and succession planning.
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As we attract and introduce a diverse pool of candidates to our industry, we have an early careers program that includes apprenticeships, youth programs (high school) and internships (college). Our programs provide a pipeline of talented students to engage in meaningful, hands-on work experiences. Our apprenticeship program combines supervised, structured on-the-job training with related instruction to produce highly skilled trade and technical workers, and builds lifetime skills and comprehensive knowledge in the high-demand technical trades necessary for our success. The apprenticeship program gives us the flexibility to tailor training to match our needs - training employees in our facilities, on our equipment, and consistent with our safety standards and employee expectations. We instill company Values, methods and procedures from day one.

2) REGULATION - Alliant Energy, IPL and WPL are subject to regulation by various federal, state and local agencies. The following includes the primary regulations impacting Alliant Energy’s, IPL’s and WPL’s businesses.

FERC -
Public Utility Holding Company Act of 2005 - Alliant Energy is registered with FERC as a public utility holding company, pursuant to the Public Utility Holding Company Act of 2005, and is required to maintain certain records and to report certain transactions involving its public utilities, service company and other entities regulated by FERC. Corporate Services, IPL and WPL are subject to regulation by FERC under the Public Utility Holding Company Act of 2005 for various matters including, but not limited to, affiliate transactions, public utility mergers, acquisitions and dispositions, and books, records and accounting requirements.

Energy Policy Act of 2005 - The Energy Policy Act of 2005 requires creation of an Electric Reliability Organization to provide oversight by FERC. FERC designated North American Electric Reliability Corporation, which also provides oversight of cybersecurity standards, as the overarching Electric Reliability Organization. Midwest Reliability Organization, which is a regional member of North American Electric Reliability Corporation, has direct responsibility for mandatory electric reliability standards for IPL and WPL.

Federal Power Act of 1935 - FERC also has jurisdiction, under the Federal Power Act of 1935, over certain electric utility facilities and operations, electric wholesale sales, interstate electric transmission rates, dividend payments, issuance of IPL’s securities, and accounting practices of Corporate Services, IPL and WPL.

Electric Wholesale Rates - FERC has authority over IPL's and WPL's wholesale electric market-based rates. Market-based rate authorization allows for wholesale sales of electricity within FERC’s wholesale markets, including the MISO market, and in transactions directly with third parties, based on the market value of the transactions. IPL and WPL also have FERC-approved cost of service formula-based rates related to the provision of firm full- and partial-requirement wholesale electric sales, which allow for true-ups to actual costs, including fuel costs.

Electric Transmission Rates - FERC regulates the rates charged for electric transmission facilities used in interstate commerce. IPL and WPL do not own or operate FERC-regulated electric transmission facilities; however, both IPL and WPL pay for the use of the interstate electric transmission system based upon FERC-regulated rates. IPL and WPL rely primarily on the use of the ITC and ATC transmission systems, respectively.

Natural Gas Act - FERC regulates the transportation and sale for resale of natural gas in interstate commerce under the Natural Gas Act. Under the Natural Gas Act, FERC has authority over certain natural gas facilities and operations of IPL and WPL.

IUB - IPL is subject to regulation by the IUB for various matters including, but not limited to, retail utility rates and standards of service, accounting requirements, the construction of EGUs, and the acquisition, sale or lease of assets with values that exceed 3% of IPL’s revenues. In Iowa, counties and cities are prohibited from regulating the sale of natural gas and propane, which supports IPL’s ability to provide gas utility service to a diversified base of retail customers and industries.

Retail Utility Base Rates - IPL files periodic requests with the IUB for retail rate changes and may base those requests on either historical or forward-looking test periods. The IUB must decide on requests for retail rate changes within 10 months of the date of the application for which changes are filed, subject to certain exceptions. The historical test periods may be adjusted for certain known and measurable changes to capital investments, cost of capital and operating and maintenance expenses consistent with IUB rules and regulations. The IUB has rules that establish minimum filing requirements for rate reviews using a forward-looking test period, and a related subsequent proceeding review after the close of the forward-looking test period. The rules provide that in the subsequent proceeding review, a utility’s actual costs and revenues will be presumed to be reasonably consistent with the forward-looking test period if the utility’s actual return on common equity falls within a standard of reasonableness of 50 basis points above to 50 basis points below the authorized return on common equity. If the utility’s actual return on common equity is outside of this range, future rates could be adjusted. In addition, the rules require that IPL must receive an order from the IUB related to the subsequent proceeding review before it can file another rate review.

Energy Efficiency - In accordance with Iowa law, IPL is required to file an energy efficiency plan (EEP) every five years with the IUB. An EEP provides a utility’s plan and related budget to achieve specified levels of electric and gas energy savings.
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IUB approval demonstrates that IPL’s EEP is reasonably expected to achieve cost-effective delivery of the energy efficiency programs. Refer to Note 1(g) for discussion of the recovery of these costs from IPL’s retail electric and gas customers.

Electric Generating Units - IPL must obtain a certificate of public convenience, use and necessity (GCU Certificate) from the IUB in order to construct a new, or significantly alter (including fuel switching) an existing, EGU located in Iowa with 25 MW or more of nameplate generating capacity. IPL’s ownership and operation of EGUs (including those located outside the state of Iowa) to serve Iowa customers is subject to retail utility rate regulation by the IUB.

Gas Pipeline Projects - IPL must obtain a pipeline permit from the IUB related to the siting of utility gas pipelines in Iowa that will be operated at a pressure over 150 pounds per square inch and will transport gas to a distribution system or single, large volume customer.

Advance Rate-making Principles - Iowa law allows Iowa utilities to request rate-making principles prior to making certain generation investments in Iowa. As a result, IPL may file for, and the IUB must render a decision on, rate-making principles for certain new EGUs located in Iowa, including any alternative energy production facility (such as a wind or solar facility, as well as battery storage constructed in combination with these facilities), combined-cycle natural gas-fired EGU, and certain base-load EGUs with a nameplate generating capacity of 300 MW or more (such as nuclear-fired generation). Advance rate-making principles are also available for the repowering of an alternative energy production facility or certain significant alterations of an existing EGU. Upon approval of rate-making principles by the IUB, IPL must either construct the EGU or repower the alternative energy production facility under the approved rate-making principles, or not at all. If rate-making principles are not approved by the IUB, IPL may construct the facility, subject to other applicable approvals (such as a GCU Certificate), subject to recovery in future rate reviews.

Electric Generating Unit Environmental Controls Projects - At its sole discretion, IPL may submit an updated emissions plan and budget to the IUB setting out a multi-year plan and budget for managing regulated emissions from its coal-fired EGUs in a cost-effective manner. IPL must simultaneously submit this plan and budget to the Iowa Department of Natural Resources for a determination of whether the plan and budget meet state environmental requirements for regulated emissions. The reasonable and prudent costs associated with implementing the approved plan are expected to be included in IPL’s future retail electric rates.

PSCW - WPL is subject to regulation by the PSCW related to its operations in Wisconsin for various matters including, but not limited to, retail utility rates and standards of service, accounting requirements, issuance and use of proceeds of securities, affiliate transactions, approval of the location and construction of EGUs and certain other additions and extensions to facilities. In addition, Alliant Energy is subject to regulation by the PSCW for the type and amount of Alliant Energy’s holdings in non-utility businesses and other affiliated interest activities, among other matters.

Retail Utility Base Rates - WPL files periodic requests with the PSCW for retail rate changes, which are based on forward-looking test periods. There is no statutory time limit for the PSCW to decide on retail base rate requests. However, the PSCW attempts to process retail base rate reviews in approximately 10 months and has the ability to approve interim retail rate relief, subject to refund, if necessary. Currently, WPL is required to defer a portion of its earnings if its annual regulatory return on common equity exceeds certain levels.

Public Benefits - WPL contributes 1.2% of its annual retail utility revenues to help fund Focus on Energy, Wisconsin’s state-wide energy efficiency and renewable energy resource program. In addition, WPL contributes to a program that provides assistance to income-eligible residents in Wisconsin. These contributions are recovered from customers through a monthly bill surcharge of the lesser of 3% of customers’ utilities bills or $750. Refer to Note 1(g) for discussion of the recovery of these costs from WPL’s retail electric and gas customers.

New Electric Generating Units - A CA application is required to be filed with the PSCW for construction approval of any new EGU (including battery storage) with a capacity of less than 100 MW and a project cost of $12.4 million or more. WPL must obtain a CPCN from the PSCW in order to construct a new EGU in Wisconsin with a capacity of 100 MW or more. In addition, WPL’s ownership and operation of EGUs (including those located outside the state of Wisconsin) to serve Wisconsin customers are subject to retail utility rate regulation by the PSCW.

Electric Generating Unit Upgrades and Electric Distribution Projects - A CA application is required to be filed with the PSCW for construction approval of any additions to EGUs, including environmental controls projects, as well as electric distribution projects, with estimated project costs of $12.4 million or more.

Gas Distribution Projects - A CA application is required to be filed with the PSCW for construction approval of gas projects with an estimated project cost of $5.9 million or more and at any time that WPL requests to extend gas service to a new portion of its service territory.

Advance Rate-making Principles - Wisconsin law provides Wisconsin utilities with the opportunity to request rate-making principles prior to the purchase or construction of any EGU utilized to serve Wisconsin customers. WPL is not obligated to file
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for or accept authorized rate-making principles under Wisconsin law. WPL can proceed with an approved project under traditional rate-making terms or accept authorized rate-making principles under Wisconsin law.

Department of Homeland Security Transportation Security Administration - Alliant Energy, IPL and WPL are subject to regulation for physical and cybersecurity of their natural gas pipeline systems, and are applying, and monitoring for changes to, these requirements to their pipeline systems.

Environmental - Alliant Energy, IPL and WPL are subject to regulation of environmental matters by federal, state and local authorities as a result of their current and past operations. Alliant Energy, IPL and WPL monitor these environmental matters and address them by installing controls that reduce emissions and by implementing operational modifications or other measures to address compliance obligations. There is currently significant regulatory uncertainty with respect to environmental rules and regulations discussed below. Given the evolving nature of environmental regulations and other related regulatory requirements, Alliant Energy, IPL and WPL develop and periodically update their compliance plans to address these environmental obligations. Prudent expenditures incurred by IPL and WPL to comply with environmental requirements are eligible to be recovered in rates from their customers. The following are major environmental matters that could potentially have a significant impact on financial condition and results of operations.

Air Quality -
Climate Change and Greenhouse Gas Regulations - In 2007, the Supreme Court provided direction on the EPA’s authority to regulate GHG and ruled that these emissions are covered by the CAA. In 2009, the EPA issued a ruling that found GHG emissions contribute to climate change and therefore threaten public health and welfare, which is the basis for implementing CO2 reduction standards under the CAA. While the EPA’s rules to regulate GHG issued under the authority of the CAA remain subject to further review, growing emphasis on climate change and evolving energy technologies are driving efforts to decarbonize the environment through voluntary emissions reductions. The primary GHG directly emitted from Alliant Energy’s utility operations is CO2 from the combustion of fossil fuels at its EGUs.

Clean Air Act Section 111(d) - In 2015, the EPA issued the Clean Power Plan rule under Section 111(d) of the CAA to reduce CO2 emissions from existing fossil-fueled EGUs through broad electricity system-wide measures. This was replaced by the Affordable Clean Energy rule in 2019, to reduce CO2 emissions from existing coal-fired EGUs through heat rate improvements. In 2021, the U.S. Court of Appeals for the District of Columbia vacated and remanded the Affordable Clean Energy rule to the EPA for reconsideration. In 2022, the Supreme Court issued a decision limiting the extent of the EPA’s authority under Section 111(d) to emissions reduction technologies and operational improvements. In May 2023, the EPA proposed the revised Section 111(d) rule, which would establish emission guidelines for states to implement Best System of Emission Reduction standards for GHG emissions from existing fossil-fueled EGUs and certain combustion turbines. The proposed requirements would be phased in beginning in 2030. The EPA also proposed to repeal the Affordable Clean Energy rule. The EPA’s proposed revised Section 111(d) rule would require states to implement plans to reduce CO2 emissions through various Best System of Emission Reduction standards by applying various measures at affected sources, including retirement, enforceable limits on operational capacity, co-firing with low-GHG fuels, or other technological controls. State plans must be submitted within 24 months of the final rule’s effective date and are subject to EPA approval. The proposed standards could impact 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. In addition, the proposed standards could impact natural gas-fired combustion turbines with a capacity of 300 MW or more, including IPL’s Marshalltown Generating Station and Emery Generating Station, and WPL’s Riverside Energy Center and West Riverside Energy Center. The proposed standards are currently not expected to impact WPL’s coal-fired Columbia Energy Center or Edgewater Generating Station given current plans to retire these EGUs prior to the proposed 2030 implementation deadline. The EPA plans to finalize the revised Section 111(d) rule in 2024. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters.

Clean Air Act Section 111(b) - In 2015, the EPA published final standards under Section 111(b) of the CAA, which establish CO2 emissions limits for certain new fossil-fueled EGUs. In May 2023, the EPA proposed revised standards under Section 111(b), which would establish CO2 emissions limits from certain new and reconstructed fossil-fueled EGUs and would apply prospectively. IPL’s Marshalltown Generating Station and WPL’s West Riverside Energy Center are currently subject to the EPA’s Section 111(b) regulation and thus would be impacted by these revised standards. The EPA plans to finalize the revised Section 111(b) rule in 2024. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these standards.

Cross-State Air Pollution Rule - CSAPR is a regional sulfur dioxide and nitrogen oxides cap-and-trade program, where compliance with emission limits may be achieved by purchasing emission allowances and/or reducing emissions through changes in operations or the additions of environmental controls. CSAPR emission allowances may be banked for future year compliance. CSAPR establishes state-specific annual sulfur dioxide and nitrogen oxides emission caps and ozone season nitrogen oxides emission caps. In 2023, the EPA finalized revisions to the CSAPR state-specific ozone season nitrogen oxides emission caps and utility-specific emission allowances for certain states, including Wisconsin, beginning in 2023. WPL currently receives, and expects to receive in the future, enough CSAPR emission allowances to ensure ongoing compliance without the need to purchase additional allowances. The 2023 CSAPR revisions do not currently apply to Iowa; however, Iowa
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could be included in a future rule. As a result, Alliant Energy and IPL are currently unable to predict with certainty the future outcome or impact of these matters.

Water Quality -
Effluent Limitation Guidelines - In 2015, the EPA published final effluent limitation guidelines that required changes to discharge limits for wastewater from certain IPL and WPL steam EGUs. In 2020, revised effluent limitation guidelines (2020 Reconsideration Rule) became effective, which incorporated flexibility to the 2015 rule, including a new subcategory for coal-fired EGUs that will be retired or converted to no longer burn coal before 2028. In 2021, the current Presidential Administration issued an Executive Order requiring the review and possible revision of environmental regulations issued during the prior Administration. As a result, in March 2023, the EPA published a proposed supplemental rule (2023 Supplemental Rule) to revise the guidelines for steam-electric generating facilities. The 2023 Supplemental Rule proposes to tighten some of the flexibility offered in the 2020 Reconsideration Rule for certain waste streams, while additionally proposing a newly defined legacy wastewater waste stream. The 2020 Reconsideration Rule will remain in effect while the 2023 Supplemental Rule continues through the rule-making process. Compliance with the 2023 Supplemental Rule will be determined by each facility’s wastewater discharge permit, and new or revised limits would become effective as soon as possible but no later than December 31, 2029. Alliant Energy, IPL and WPL are currently evaluating the 2023 Supplemental Rule and are unable to predict with certainty future compliance impacts.

Land and Solid Waste -
Coal Combustion Residuals Rule - The CCR Rule, which became effective in 2015, regulates CCR as a non-hazardous waste. IPL and WPL have coal-fired EGUs with coal ash ponds and active CCR landfills that are impacted by this rule. In May 2023, the EPA published proposed amendments to the CCR Rule that would 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 proposed 2023 CCR Rule amendments and are unable to predict with certainty the future outcome or impact of these updates.

Manufactured Gas Plant Sites - Refer to Note 17(e) for discussion of IPL’s and WPL’s MGP sites.

Renewable Energy Standards - Iowa and Wisconsin have renewable energy standards, which establish the minimum amount of energy IPL and WPL must supply from renewable resources. IPL primarily relies upon renewable energy generated from the wind resources it owns and renewable energy acquired under PPAs to meet these requirements. WPL utilizes its current renewable portfolio, which primarily consists of wind, solar and hydro energy, both owned and acquired under PPAs, to meet these requirements. IPL and WPL currently exceed their respective renewable energy standards requirements.

3) STRATEGY - Refer to “Overview” in MDA for discussion of Alliant Energy’s strategy, which supports its mission to deliver energy solutions and exceptional service that its customers and communities count on - affordably, safely, reliably and sustainably.

C. INFORMATION RELATING TO UTILITY OPERATIONS
Alliant Energy’s utility business (IPL and WPL) has three segments: a) electric operations; b) gas operations; and c) other, which includes IPL’s steam operations and the unallocated portions of the utility business. IPL’s and WPL’s electric, gas and other revenues as a percentage of total revenues were as follows:
IPLWPL
370371372373
1) ELECTRIC UTILITY OPERATIONS
General - Electric utility operations represent the largest operating segment for Alliant Energy, IPL and WPL. Alliant Energy’s electric utility operations are located in the Midwest with IPL providing retail electric service in Iowa and WPL providing retail and wholesale electric service in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa. Refer to the “Electric Operating Information” tables for additional details regarding electric utility operations.

Customers - IPL and WPL provide electric utility service to a diversified base of retail customers in several industries, with the largest concentrations in the farming, agriculture, industrial manufacturing, chemical (including ethanol), packaging and food
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industries. IPL and WPL also sell electricity to wholesale customers, which primarily consist of municipalities and rural electric cooperatives.

Seasonality - Electric sales are seasonal to some extent with the annual peak normally occurring in the summer months due to air conditioning requirements. Electric sales are also impacted to a certain extent in the winter months due to heating requirements.

Competition - Retail electric customers in Iowa and Wisconsin currently do not have the ability to choose their electric supplier, and IPL and WPL have obligations to serve all their retail electric customers. Although electric service in Iowa and Wisconsin is regulated, IPL and WPL still face competition from self-generation by large industrial customers, customer- and third party-owned generation (e.g. solar panels), alternative energy sources, and petitions to municipalize (Iowa) as well as service territory expansions by municipal utilities through annexations (Wisconsin). In addition, the wholesale power market is competitive and IPL and WPL compete against independent power producers, other utilities and MISO market purchases to serve wholesale customers for their electric energy and capacity needs. Alliant Energy’s strategy includes actions to retain current customers and attract new customers into IPL’s and WPL’s service territories in an effort to keep energy rates low for all of their customers. Refer to “Overview” in MDA for discussion of the strategy element focusing on growing customer demand.

Electric Supply - Alliant Energy, IPL and WPL have met, and expect to continue meeting, customer demand of electricity through a mix of electric supply, including owned EGUs, PPAs and additional purchases from wholesale energy markets. Alliant Energy expects its mix of electric supply to change in the next several years with its planned transition away from coal-fired EGUs by considering additional renewable energy such as solar generation, battery storage, repowering of existing wind farms and distributed energy resources, including community solar and small-scale energy storage systems, dispatchable gas generation projects, and potential sales of partial interests in West Riverside to neighboring utilities. Long-term generation plans are intended to meet customer demand, reduce air emissions and water impacts, reduce reliance on wholesale market purchases and mitigate the impacts of future EGU retirements while maintaining compliance with long-term electric demand planning reserve margins, renewable energy standards established by regulators and other various requirements.

Electric Demand Planning Reserve Margin - IPL and WPL are required to maintain a planning reserve margin above their load at the time of the MISO-wide peak to ensure reliability of electric service to their customers. IPL and WPL utilize accredited capacity from EGUs they own, and have rights to through PPAs, to meet a substantial portion of their current MISO planning reserve margin requirements and periodically rely on short-term market capacity purchases to supplement the accredited capacity from such EGUs.

MISO Seasonal Resource Adequacy Process - In 2022, FERC approved MISO’s proposal to change its resource adequacy process establishing capacity planning reserve margin and capacity accreditation requirements effective with the June 1, 2023 through May 31, 2024 MISO Planning Year, to help ensure the reliability of electricity in the MISO region. The process changed from a Summer-based annual construct to four distinct seasons. FERC’s approval also established planning reserve margin requirements for all market participants on a seasonal basis and determined a seasonal accredited capacity value for certain classes of generating resources, including higher accredited capacity for wind generation during the Spring, Fall and Winter seasons and higher accredited capacity for solar generation during the Summer season. Alliant Energy, IPL and WPL currently plan to construct and/or acquire additional renewable, battery and natural gas resources to meet the requirements of the seasonal resource adequacy process and have reflected the estimated capital expenditures for these projects in the “Generation” lines in the construction and acquisition table in “Liquidity and Capital Resources.” Seasonal capacity reserve margins are as follows:
June 2024 - August 2024
September 2024 - November 2024
December 2024 - February 2025
March 2025 - May 2025
Required installed capacity reserve margin17.7%25.2%49.4%40.8%
Required unforced capacity reserve margin9.0%14.2%27.4%26.7%

Generation Fuel Supply - IPL and WPL own a portfolio of EGUs located in Iowa, Wisconsin and Minnesota with a diversified fuel mix that includes natural gas, renewable resources and coal. Refer to “Properties” in Item 2 for details of IPL’s and WPL’s EGUs. The average cost of delivered fuel per million British Thermal Units used for electric generation was as follows:
IPLWPL
202320222021202320222021
All fuels$2.83$4.37$2.10$3.09$4.47$2.62
Natural gas (a)3.105.762.543.476.023.31
Coal2.092.311.812.542.432.07

(a)The average cost of natural gas includes commodity and transportation costs, as well as realized gains and losses from swap and option contracts used to hedge the price of natural gas volumes expected to be used by IPL’s and WPL’s natural gas-fired EGUs.

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Natural Gas - Alliant Energy, IPL and WPL own several natural gas-fired EGUs, and WPL also has exclusive rights to the output of AEF’s Sheboygan Falls Energy Facility under an affiliated lease agreement. These facilities help meet customer demand for electricity when natural gas prices are low enough to make natural gas-fired generation economical compared to other fuel sources. Alliant Energy manages the gas supply to these gas-fired EGUs and helps ensure an adequate supply is available at known prices through a combination of gas commodity, pipeline transportation and storage agreements held by IPL and WPL for numerous years. Alliant Energy, IPL and WPL believe they are reasonably insulated against gas price volatility for these EGUs given their use of forward contracts and hedging practices, as well as their regulatory cost-recovery mechanisms.

Coal - Coal is one of the fuel sources for owned EGUs. Coal contracts entered into with different entities help ensure that a specified supply of coal is available, and delivered, at known prices for IPL’s and WPL’s coal-fired EGUs. Alliant Energy, IPL and WPL believe their coal supply portfolio represents a reasonable balance between the risks of insufficient supplies and those associated with being unable to respond to future coal market changes. Remaining coal requirements are expected to be met from either future term contracts or purchases in the spot market. Currently, all of the coal utilized by IPL and WPL is from the Wyoming Powder River Basin.

Alliant Energy, IPL and WPL believe they are reasonably insulated against coal price volatility given their current coal procurement process, the specific coal market in their primary purchase region and regulatory cost-recovery mechanisms. The coal procurement process supports periodic purchases, staggering of contract terms, stair-stepped levels of supply going forward and supplier diversity. Similarly, given the term lengths of their transportation agreements and strategic alignment of agreement expirations for negotiation purposes, Alliant Energy, IPL and WPL believe they are reasonably insulated against future higher coal transportation rates from the major railroads.

Purchased Power - IPL and WPL periodically enter into PPAs and purchase electricity from wholesale energy markets to meet a portion of their customer demand for electricity.

Electric Transmission - IPL and WPL do not own electric transmission service assets and currently receive transmission services from ITC and ATC, respectively. ITC and ATC are independent, for-profit, transmission-only companies and are transmission-owning members of the MISO Regional Transmission Organization, Midwest Reliability Organization and Reliability First Corporation Regional Entities. The annual transmission service rates that ITC or ATC charges their customers are calculated each calendar year using a FERC-approved cost of service formula rate. As a result, ITC and ATC can implement new rates each calendar year without filing a request with FERC. However, new rates are subject to challenge by either FERC or customers. If the rates proposed by ITC or ATC are determined by FERC to be unjust or unreasonable, or another mechanism is determined by FERC to be just and reasonable, ITC’s or ATC’s rates would change accordingly. Refer to Note 1(g) for discussion of a transmission cost rider utilized by IPL for recovery of its electric transmission service expense, and discussion of WPL’s escrow for recovery of electric transmission service expense, which is recovered from its retail electric customers through changes in base rates determined during periodic rate proceedings. Refer to Note 17(g) for discussion of a court decision, which is currently expected to reduce the base return on equity authorized for MISO transmission owners, including ATC.

MISO Markets - IPL and WPL are members of MISO, a FERC-approved Regional Transmission Organization, which is responsible for monitoring and ensuring equal access to the transmission system in their footprint. IPL and WPL participate in the wholesale energy and ancillary services markets operated by MISO, which are discussed in more detail below. As agent for IPL and WPL, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases between IPL and WPL based on statements received from MISO.

Wholesale Energy Market - IPL and WPL sell and purchase power in the day-ahead and real-time wholesale energy markets operated by MISO. MISO’s bid/offer-based markets compare the cost of IPL and WPL generation against other generators, which affects IPL and WPL generation operations, energy purchases and energy sales. MISO generally dispatches the lowest cost generators, while recognizing current system constraints, to reduce costs for purchasers in the wholesale energy market. In addition, MISO may dispatch generators that support reliability needs, but that would not have operated based on economic needs. In these cases, MISO’s settlement assures that these generators are made whole financially for their variable costs.

Ancillary Services Market - IPL and WPL also participate in MISO’s ancillary services market, which integrates the procurement and use of regulation and contingency reserves with the existing wholesale energy market to ensure reliability of electricity supply. MISO’s ancillary services market has had the overall impact of lowering ancillary services costs in the MISO footprint.

Financial Transmission Rights and Auction Revenue Rights - In areas of constrained transmission capacity, energy costs could be higher due to congestion and its impact on locational marginal prices. FTRs provide a hedge for certain congestion costs that occur in the MISO energy market. MISO allocates auction revenue rights to IPL and WPL annually based on a fiscal year from June 1 through May 31 and historical use of the transmission system. The allocated auction revenue rights are used by IPL and WPL to acquire FTRs through the FTR auctions operated by MISO.

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Resource Adequacy - MISO has resource adequacy requirements to help ensure adequate resources to meet forecasted peak load obligations plus a reserve margin. Only accredited capacity assigned to EGUs is available to meet these requirements. In order for an EGU to receive accredited capacity, it must meet MISO capacity accreditation requirements, which can include satisfying transmission requirements identified in its interconnection agreement prior to the MISO planning year. Refer to “Electric Demand Planning Reserve Margin” above for discussion of MISO’s seasonal resource adequacy process establishing capacity planning reserve margin and capacity accreditation requirements.

Electric Operating Information - Alliant Energy202320222021
Revenues (in millions):
Residential$1,220 $1,233 $1,115 
Commercial820 821 763 
Industrial968 965 893 
Retail subtotal3,008 3,019 2,771 
Sales for resale:
Wholesale213 233 187 
Bulk power and other71 111 56 
Other53 58 67 
Total$3,345 $3,421 $3,081 
Sales (000s MWh):
Residential7,176 7,479 7,353 
Commercial6,329 6,436 6,383 
Industrial11,435 11,494 11,696 
Retail subtotal24,940 25,409 25,432 
Sales for resale:
Wholesale2,859 2,866 2,787 
Bulk power and other4,730 3,734 3,018 
Other58 62 71 
Total32,587 32,071 31,308 
Customers (End of Period):
Retail995,982 989,369 981,570 
Other2,914 2,903 2,878 
Total998,896 992,272 984,448 
Other Selected Electric Data:
Maximum summer peak hour demand (MW)5,856 5,629 5,486 
Maximum winter peak hour demand (MW)4,240 4,415 4,413 
Cooling degree days (a):
Cedar Rapids, Iowa (IPL) (normal - 819)
974 908 974 
Madison, Wisconsin (WPL) (normal - 706)
781 787 845 
Sources of electric energy (000s MWh):
Gas14,764 11,438 10,055 
Purchased power:
Wind (b)4,067 4,422 3,529 
Other (b)1,883 2,803 2,642 
Wind (b)5,410 6,424 5,231 
Solar (b)471 41 17 
Coal6,447 7,416 10,218 
Other (b)186 198 209 
Total33,228 32,742 31,901 
Revenue per KWh sold to retail customers (cents)12.06 11.88 10.90 
(a)Cooling degree days are calculated using a simple average of the high and low temperatures each day compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical cooling degree days. Refer to “Gas Operating Information” below for details of heating degree days.
(b)All or some of the renewable energy attributes associated with generation from these sources may be used in future years to comply with renewable energy standards or other regulatory requirements.

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Electric Operating InformationIPLWPL
202320222021202320222021
Revenues (in millions):
Residential$641 $673 $620 $579 $560 $495 
Commercial519 536 508 301 285 255 
Industrial501 538 505 467 427 388 
Retail subtotal1,661 1,747 1,633 1,347 1,272 1,138 
Sales for resale:
Wholesale62 64 57