AMEREN CORP

Missouri and Illinois laws require electric utilities to include renewable energy resources in their portfolios. Ameren Missouri and Ameren Illinois satisfied their renewable energy resource requirements in 2025, pending regulatory review by the MoPSC for Ameren Missouri.

In Missouri, utilities are required to purchase or generate electricity equal to at least 15% of native load sales from renewable energy sources, with at least 2% of the requirement derived from solar energy. The requirement is subject to an average 1% annual limit on increases to customer rates over any 10-year period. For renewable generation facilities located in Missouri, 125% of the electricity generated counts towards meeting the requirement. Ameren Missouri expects to satisfy the requirement in 2026 with its High Prairie, Atchison, Huck Finn, Keokuk, Maryland Heights, and other solar energy centers, along with other renewable energy credits purchased by Ameren Missouri, including solar-generated renewable energy credits purchased from customer-installed systems.

In accordance with Illinois law, Ameren Illinois is required to collect funds from all electric distribution customers to fund IPA procurement events for renewable energy credits. The amount set by law and required to be collected from customers by Ameren Illinois is currently $4.58 per MWh. Beginning June 2026, the CRGA will increase the amount of customer collections by adding an annual inflation adjustment to the $4.58 per MWh charge. The IPA establishes its long-term renewable resources procurement plans in a filing made every two years. In February 2026, the ICC approved the IPA’s latest long-term renewable resources procurement plan, which established the 2026 and 2027 renewable energy credit procurement targets. Based on IPA procurement events that align with the IPA’s plan, Ameren Illinois has contractual commitments to purchase approximately 3.1 million wind renewable energy credits per year and approximately 4.1 million solar renewable energy credits per year. Ameren Illinois has also entered into contracts, ending in 2032, to purchase approximately 0.6 million wind renewable energy credits per year. Pursuant to the CEJA, if funds collected from customers are not used to procure renewable energy credits, they would be refunded to customers pursuant to an annual reconciliation proceeding. The first two reconciliations, covering June 2017 through May 2018 and June 2018 through May 2019, were approved by the ICC in January 2025 and May 2025, respectively, and did not result in refunds to customers. Based on amounts collected from customers and obligations under the program, the June 2019 through May 2020 reconciliation period is not expected to result in refunds to customers, pending review by the ICC.

The CRGA establishes an energy storage credit program, under which the IPA must hold statewide procurements for energy storage credits. The program requires Illinois utilities to enter into 20-year contracts to procure energy storage credits, with delivery of the credits beginning no later than 2030. Ameren Illinois anticipates utilizing cost recovery mechanisms to allow Ameren Illinois to collect from, or refund to, customers differences between actual costs incurred from the purchase of the credits and the amounts collected from customers. For additional information regarding the CRGA, see Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report.

Illinois law also required Ameren Illinois to enter into contracts to purchase zero emission credits in an amount equal to approximately 16% of the actual amount of electricity delivered to retail customers during calendar year 2014, pursuant to Illinois’ zero emission standard. As a result of a 2018 IPA procurement event, which was approved by the ICC, Ameren Illinois entered into agreements to acquire zero emission credits through May 2027. Annual zero emission credit commitment amounts will be published by the IPA each May prior to the start of the subsequent planning year. Both renewable energy credits and zero emission credits have cost recovery mechanisms, which allow Ameren Illinois to collect from, or refund to, customers differences between actual costs incurred from the purchase of the credits and the amounts collected from customers.