This case does not change what a household pays today, but it is the main tool Illinois regulators are using to try to stop the cost of new grid equipment for data centers from landing on residential bills.
no figure yet
PJM capacity auction price spike hits ComEd supply charges
On bills now Supply and capacity price before the Illinois Commerce Commission.
+$11a month
on a typical bill, as approved
As published by the utility or the commission.
Fileddate not published
Hearingheld or waived
Decisiondecided
On billsJun 1, 2025
PJM, the regional grid operator for ComEd's territory, saw its capacity auction price jump from 28.92 dollars per megawatt day to 269.92 dollars per megawatt day, a roughly 830 percent increase, largely because of surging data center demand across the PJM footprint. That flowed into ComEd's supply price starting June 1, 2025, adding an estimated 10.50 dollars a month to an average residential bill. The next PJM auction came in at 329.17 dollars per megawatt day, about 22 percent higher again, which is expected to push ComEd supply prices up further starting June 2026.
What it means for your bill: This is the single biggest reason ComEd bills jumped in summer 2025 and again in 2026, and PJM and consumer groups both tie it directly to data center demand growth.
- Status
- On bills now
- Utility
- Commonwealth Edison
- Commission
- Illinois Commerce Commission
- Typical bill change
- +$10.50 a month
- On bills from
- June 1, 2025
- Data center linked
- Yes. The filing ties part of the cost or the tariff design to data center load.
- Last checked
- August 29, 2026
Sources
- PJM Capacity Auction Leads to Record Price Spike for Second Straight Year, Threatens Even Higher ComEd Bills in 2026-27, Citizens Utility Board, 2025-07-22
- CUB Q&A: Why is ComEd's electricity price spiking?, Citizens Utility Board, 2025-05-09
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Other Commonwealth Edison matters
This is a routine annual true up of ComEd's delivery charges, not something tied to data centers, and it adds a few dollars a month to a typical bill.
+$3a month
This is the base multi-year plan that sets the delivery portion of a ComEd household bill through 2027, separate from the newer data center specific tariff cases.
no figure yet