On October 24, 2022, the Federal Energy Regulatory Commission (FERC) approved a system support resource (SSR) agreement for Ameren Missouri’s 1,195-MW Rush Island power plant, stating that the coal plant is necessary to maintain grid reliability.[1] The SSR agreement can be renewed annually, and the contract will be paid for by load-serving entities that benefit from keeping Rush Island open. In a separate decision, FERC said the proposed monthly payments Ameren Missouri would receive for running the plant need further review through a hearing process.[2] FERC also rejected Ameren Missouri’s request for an additional 0.5% return on equity (ROE) for cost recovery for keeping the plant open longer than expected, stating that the ROE adder only applies to transmission facilities.

The Rush Island Power plant was originally set to retire on September 1, 2022. Instead, Ameren Missouri now expects to keep it running until mid-2025 to support grid reliability. According to the Midcontinent Independent System Operator (MISO), retiring the coal plant could cause severe voltage stability problems, leading to cascading power outages. In MISO’s application for an SSR agreement, the grid operator identified four transmission upgrades that are needed to maintain voltage on the grid, with the last one expected to be online by June 2025. Potential renewable energy additions or demand-response programs wouldn’t be enough.

[1] https://elibrary.ferc.gov/eLibrary/filelist?accession_number=20221024-3065&optimized=false

[2] http://elibrary.ferc.gov/eLibrary/filelist?accession_number=20221024-3066&optimized=false