Illinois Storage Auction Buys 520 MW Downstate and Only 80 MW in ComEd Territory, 438 MW Short of Target
- Total procured: 600 MW
- Procurement target: 1,038 MW
- Average winning strike price: $110.52 per MWh
- ComEd shortfall: 508 MW
- Contract term: 20 years
The Illinois Commerce Commission approved the results of the state’s first utility-scale energy storage auction on September 1, 2026. Five projects won 20-year contracts for a combined 600 MW. The Illinois Power Agency had targeted 1,038 MW. The auction therefore filled 58 percent of what the state asked for, and the shortfall of 438 MW sits almost entirely in the Chicago area.
The Agency ran two separate procurements. Ameren Illinois, inside MISO Zone 4, asked for 450 MW and bought 520 MW. Commonwealth Edison, inside the PJM ComEd locational deliverability area, asked for 588 MW and bought 80 MW. That leaves 508 MW unbought in ComEd territory.
The Five Winners
Four of the five projects sit downstate in Ameren territory. Gatehouse Energy Storage won 185 MW at Du Bois. Key Capture Energy won two 100 MW contracts, KCE IL 1 at Flora and KCE IL 2 at Herrick. McDuff Battery Storage won 135 MW at Casey. In ComEd territory, Lincoln Reserve Energy won a single 80 MW contract at Calumet City.
The Agency published one price for the whole auction rather than a price per project. The average winning strike price was $110.52 per MWh. Winners sign Indexed Storage Credit contracts, which settle each day against a reference price built from energy arbitrage and capacity revenue. When market revenue runs above the strike price, the supplier pays the utility. When it runs below, the utility pays the supplier.
Ameren exceeded its own target on purpose. The auction rules allow a procurement to run up to 50 percent past target to fit the last project. Three of the five winning projects sit at least half inside an Energy Transition Community Grant Area.
The Terms Are Strict
Every project must reach commercial operation by December 31, 2029. A developer buys an extension to December 31, 2030 by posting more collateral. Each project needs a minimum contract capacity of 20 MW and four hours of continuous discharge. Round-trip efficiency must stay at or above 70 percent, and must reach 85 percent in the first delivery year. Each project must stay available 4,320 hours per delivery year. The rules count a project as new only if it energizes on or after June 1, 2026.
Why It Matters
The Clean and Reliable Grid Affordability Act orders 3,000 MW of storage under contract for commercial operation by the end of 2030. This auction delivered 600 MW of that. Two more procurements follow, in 2027 and 2028. They now have to find 2,400 MW, not the 1,962 MW a full first round would have left.
The gap matters most because of where it fell. ComEd serves the Chicago load pocket, the part of Illinois that sits inside PJM. Illinois wrote a procurement to put batteries there and came away with one project of 80 MW. The published record names winners, not bidders. Neither the Agency nor the Commission has said whether ComEd developers bid and lost on price, or did not bid at all. Until Illinois says which, the thin ComEd result stays unexplained in the public file.
For anyone pricing storage in Illinois, the strike price is the number to carry forward. At $110.52 per MWh across a four-hour product, the state now has a public benchmark for a 20-year indexed contract in the Midwest. The next two auctions will test whether 508 MW of unmet ComEd demand pulls that number up.
Critical Perspective
The 600 MW headline hides which region did the work. Ameren bought 116 percent of its 450 MW target, and the rules permitted that overshoot. Illinois therefore reports a 600 MW procurement while the zone it most wanted to serve produced one project of 80 MW. Read the two procurements apart and the first round looks less like a partial success than like a downstate result carrying a Chicago failure.
The single published price also carries less information than it appears to. The $110.52 per MWh figure averages five contracts across two wholesale markets, from a 185 MW downstate project in MISO to an 80 MW project inside PJM. A developer pricing a ComEd site learns almost nothing from a number that blends it with four Ameren winners. The Agency published what the statute requires, which is not the same as what a bidder needs.
The contract terms move real risk onto the developer. An Indexed Storage Credit pays the supplier when market revenue runs below the strike price and takes money back when it runs above, so this is a hedge rather than a subsidy. Layer on 85 percent round-trip efficiency in the first delivery year, 4,320 available hours per delivery year, and a hard commercial operation date of December 31, 2029. That deadline depends on the same interconnection process that returned a single ComEd winner.
Sources
- https://www.ipa-energyrfp.com/announcements/energy-storage-rfp-announcement-icc-has-approved-the-results-of-the-summer-2026-energy-storage-rfp/
- https://nera-content-media.s3.us-east-1.amazonaws.com/ipa/Summer_2026_Energy_Storage_RFP_Results_01_SEP_2026_eb934945bd.pdf
- https://nera-content-media.s3.us-east-1.amazonaws.com/ipa/Public_Notice_of_August_2026_Energy_Storage_Procurement_Results_2026_09_01_97ba2f4392.pdf
- https://www.ipa-energyrfp.com/energy-storage/
- https://keycaptureenergy.com/kceil2/
