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Ameren Illinois Customers Benefit From Federal Ruling

The Federal Energy Regulatory Commission (FERC) has issued its final order in response to complaints filed with the agency about the outcome of an energy capacity auction conducted last spring that resulted in huge price spikes for Midcontinent Independent System Operator (MISO) customers in Illinois.   FERC agreed with the Illinois Attorney General – and Ameren Illinois, a complainant in the case filed by the state and other watchdog groups and utilities – that the process used to set capacity prices in MISO is no longer just and reasonable and must be modified prior to the next MISO capacity planning auction.  This ruling could lead to short-term rate relief for Ameren Illinois customers.


“Our position has always been that the process for establishing capacity costs should be fair and just, and not unduly burden Ameren Illinois customers,” said Richard J. Mark, president of Ameren Illinois. “We have spent the last several months appealing to FERC on behalf of utility customers in central and southern Illinois in support of a review of the MISO auction. FERC’s ruling provides an encouraging sign that issues with the capacity auction process are being addressed, and that our customers can expect stable prices in the future.”



  • The MISO capacity auction for the zone that serves Ameren Illinois customers resulted in a price increase 40-times higher than other MISO zones.  That increased the annual electricity bill by approximately $9 per month for the typical residential customer. 
  • Federal rules require Ameren Illinois to procure electric capacity at the auction price from MISO. Capacity charges are included in the overall cost of energy supply. As a delivery-only company, Ameren Illinois passes the cost of supply directly to its customers and does not profit from increases in supply costs.
  • Ameren Illinois petitioned FERC in support of a review of the MISO auction and a determination as to whether customer refunds are warranted and forward looking changes are necessary.   
  • The company has also been an active participant in recent policy discussions overseen by the Illinois Commerce Commission.  These policy discussions addressed the tradeoffs between customer costs and maintaining long term reliability.  Ameren Illinois will continue to be an active stakeholder in the search for a modified MISO capacity auction that provides stable prices in the future, while also ensuring that reliability is maintained. 



About Ameren Illinois
Ameren Illinois delivers energy to 1.2 million electric and 816,000 natural gas customers in downstate Illinois, and our mission is to power the quality of life. Our service territory covers more than 1,200 communities and 43,700 square miles. For more information, visit AmerenIllinois.com.  Follow us on Twitter @AmerenIllinois and Facebook.