news7 min read

Will Your Illinois Electric Bill Go Back Down? PJM Just Locked In Prices Through 2029

Ryan Cook•July 16, 2026•Updated Sep 13, 2026

Short answer: not soon. On July 14, 2026, PJM announced that its capacity auction for the 2028-29 delivery year cleared at $325 per megawatt-day — the third auction in a row to clear at the FERC-approved price cap. That means the capacity piece of a ComEd bill is set at that level through May 31, 2029.

I've been telling customers for two years that Illinois electric rates went up because of a "spike." I need to correct myself. It's not a spike anymore. It's a plateau — and we now know it holds through at least May 2029.

PJM is the grid operator for northern Illinois and ComEd. Its newest result is the clearest answer yet to the question I get more than any other: when does my bill go back down?

The "spike" people keep waiting to reverse

When a price jumps, most of us assume it'll ease back. That's the instinct I hear on every call — "I'll wait for rates to settle before I do anything about solar."

Here's what the auction results actually look like (PJM Base Residual Auction clearing prices, RTO-wide):

PJM delivery year	Capacity price ($/MW-day)	Auction result announced
2024-25	$28.92	—
2025-26	$269.92	—
2026-27	$329.17 (price cap)	July 22, 2025
2027-28	$333.44 (price cap)	Dec. 17, 2025
2028-29 (new)	$325.00 (price cap)	July 14, 2026

Look at that column. The jump from $28.92 to $269.92 was the shock everyone felt on their 2025 and 2026 bills. But the three years after it don't come back down — they sit in a band around $325 to $333. The market didn't correct. It found a new, much higher floor. And PJM's own report says that without the cap, the 2028-29 price would have been far higher still.

That matters because capacity is set at auction years in advance. The 2028-29 number was decided in July, in a bidding window that ran June 30 through July 7, 2026. It's already locked. Nobody's waiting on a future event to find out where that piece of the bill lands — it landed.

What a "capacity price" even is

Quick version, because it's easy to glaze over. Capacity is the grid paying power plants to promise they'll show up on the hottest, highest-demand days. ComEd sits inside PJM, so whatever PJM's auction clears at gets passed to ComEd customers as a capacity charge.

Citizens Utility Board pegs capacity costs at roughly 20 percent of the price ComEd customers pay for electricity — and it's the fastest-growing piece. CUB also notes ComEd customers are now paying a power price about 50 percent higher than two years ago.

Why did it climb? Mostly data centers. They're adding enormous new demand, the auction has to secure more supply to cover it, and the price rises for everyone. I did a full breakdown of that in my data centers and your electric bill piece — start there if you want the mechanism and the numbers behind the buildout. For this post, the point is narrower: the newest auction confirms the trend isn't reversing.

So when does my bill go back down?

For the capacity piece, the honest answer is: not through the 2028-29 delivery year, because it's already priced. Your supply and delivery charges will still wiggle around — supply resets every June 1 and October 1, delivery depends on pending rate cases — but the part that's been driving the increases is committed at a high level for years out.

Downstate isn't off the hook either. Central and southern Illinois run on MISO, not PJM, and MISO's own capacity price spiked hard — its summer 2025 price cleared at $666.50 per megawatt-day in the 2025-26 auction. Ameren Illinois passes that straight through, same as ComEd does up north, and Ameren's next multi-year delivery rate plan, covering 2028 through 2031, is due to be filed in 2027. Its summer supply price sits at 11.326 cents per kilowatt-hour through September 30, 2026, which puts the estimated all-in summer rate near 19 cents. My Ameren bill and MISO post walks through that side in detail.

North or south, it's the same shape: capacity-driven costs, set in advance, with no relief on the calendar.

What's being done about it

I don't want to leave you thinking nobody's fighting this. Plenty of people are.

CUB is pushing three specific reforms off this latest auction: PJM should require data centers that don't bring their own new power to be interruptible on peak days; Illinois should pass the state POWER Act, which would make data centers pay their own interconnection costs and bring new capacity instead of leaning on residential customers; and Congress should pass the federal Power for the People Act. Governor Pritzker also directed the state to pause new Data Center Investment Program tax-incentive agreements starting July 1, 2026.

Those are real steps, and I hope they land. But I'll be straight with you: none of them un-price an auction that already cleared. The 2026-27, 2027-28, and 2028-29 capacity costs are set. Even a good reform passed this year mostly protects the auctions that haven't happened yet.

That's the piece I want you to sit with. Waiting for policy to lower the bill you're paying now is a long bet on a slow process.

The part you actually control

You can't vote in a capacity auction. You can't stop the next data center in Joliet or DeKalb. But you can decide what rate you pay for the power your own roof makes.

A solar lease in Illinois can start at a predictable rate as low as 10 cents per kilowatt-hour for the 25-year term — the full rate schedule is set in your contract before you sign. Compare that with this summer's estimated all-in rates of roughly 17 cents for ComEd and 19 cents for Ameren. That number doesn't care what PJM clears at in 2028. You know your number for 25 years because the schedule is in your contract.

For income-qualified households, Solar for All offers "guaranteed savings with no solar payment & reduced utility bills" — that's the program's own language, not a claim I'm making. And if outages worry you as much as cost, a battery paired with Illinois's $300-per-kWh utility battery rebate keeps your fridge and sump pump running when the grid strains — which, given the reliability warnings tied to this same demand growth, is worth a look.

I'm a local installer with trusted Illinois partners, so I can show you lease, cash, and Solar for All side by side and let the numbers decide. Run yours on the Solar Savings Calculator, look up current ComEd and Ameren rates, or just call me at (618) 217-2001.

The auction already told us where rates are headed through 2029. The only open question is whether you're along for that ride or you already know your own number.

Sources

Frequently Asked Questions

Not in the near term, and the reason is already locked in. The biggest driver of recent increases is the PJM capacity charge, which is set years ahead at auction. On July 14, 2026, PJM announced its newest result: the 2028-29 delivery year cleared at $325 per megawatt-day — the third straight auction to clear at the FERC-approved price cap, after $329.17 for 2026-27 and $333.44 for 2027-28. Two auctions before that, the price was $28.92. So the capacity piece of a northern-Illinois bill is committed at a high level through May 31, 2029. That doesn't mean every part of your bill is frozen — supply and delivery charges still move — but the piece that has been climbing the fastest isn't scheduled to fall. If you've been waiting for rates to drop before acting, the auction just told you how long that wait is likely to be.

The PJM capacity auction is how the grid operator for northern Illinois pays power plants to promise they'll be available on the highest-demand days, usually years in advance. ComEd sits inside PJM, so whatever that auction clears at flows into ComEd customer bills as a capacity charge. When data centers pile huge new demand onto the grid, the auction has to secure more capacity, and the price climbs. That's most of what happened here: prices went from $28.92 per megawatt-day for 2024-25 to the $325-$333 range for the three delivery years running through May 2029. Citizens Utility Board says capacity costs are roughly 20 percent of the price ComEd customers pay for electricity, and it's the fastest-growing piece. I explain the full mechanism, including the data-center numbers, in my [data centers and your bill](/blog/data-centers-illinois-electric-bill/) breakdown if you want the deeper version.

Citizens Utility Board puts capacity costs at roughly 20 percent of the price ComEd customers pay for electricity, and CUB says ComEd customers are now paying a power price about 50 percent higher than they were just two years ago. That capacity slice is the very part driven by the PJM auction, which is why it has grown so fast. The rest of your bill splits between supply (the actual energy) and delivery (the wires, poles, and ComEd's own costs), plus taxes and smaller line items. Here's the catch: because capacity is set at auction years ahead, that 20 percent is effectively pre-committed at a high level through the 2028-29 delivery year. Cutting your bill by trimming usage still helps, but you can't shop your way out of a capacity charge baked into the rate. That structural piece is a big reason I point people toward a predictable solar rate instead of waiting for the market to ease.

Yes, and the mechanism is similar even though the grid operator is different. Central and southern Illinois sit in MISO, not PJM, and MISO's own capacity price jumped sharply — its summer 2025 price cleared at $666.50 per megawatt-day in the 2025-26 auction. Ameren passes those capacity costs straight through to customers, the same way ComEd does in the north. On top of that, Ameren's next multi-year delivery rate plan, covering 2028 through 2031, is due to be filed in 2027, and its summer supply price sits at 11.326 cents per kilowatt-hour through September 30, 2026, which puts the estimated all-in rate near 19 cents this summer. So whether you're a ComEd customer up north or an Ameren customer downstate, the same story holds: capacity-driven increases that are set in advance, with no near-term relief on the calendar. You can compare both utilities on my [ComEd](/comed-rates/) and [Ameren](/ameren-rates/) rate pages.

The one lever you fully control is where your power comes from. A solar lease in Illinois can start at a predictable rate as low as 10 cents per kilowatt-hour for the 25-year term — the full rate schedule is set in your contract before you sign — against this summer's estimated all-in rates of roughly 17 cents for ComEd and 19 cents for Ameren. That number doesn't move when the next PJM or MISO auction clears high again. For income-qualified households, Illinois Solar for All offers "guaranteed savings with no solar payment & reduced utility bills" — that's the program's own language, not a sales promise — and you can check your [eligibility](/solar-for-all/) in about 30 seconds. A battery adds outage backup, and Illinois's utility battery rebate of $300 per kilowatt-hour of storage lowers the upfront cost. Run your own numbers on the [savings calculator](/calculator/), or call me at (618) 217-2001 and I'll walk your bill with you.