Quick answer
Mostly because the price of the power itself rose. Grid capacity prices for northern Illinois jumped more than tenfold after 2024, lifting ComEd's supply price from about 6.5¢ per kWh in early 2025 to 10.4¢ in summer 2026. Delivery rates rose in January 2026, and a nuclear credit that softened bills early in 2026 ended in May.
What changed on ComEd bills in 2025 and 2026?
| When | What changed | Effect on bills |
|---|---|---|
| June 2025 | Grid capacity costs for the ComEd region rose about ninefold | Supply prices up about 50%, CUB says |
| October 2025 | Supply price set at 9.689¢/kWh | About 47% higher than the previous October |
| January 2026 | Delivery rate increase approved by the ICC | About $3.10 more a month on a typical bill |
| January to May 2026 | Nuclear credit on the Carbon-Free Energy Resource Adjustment line | About $13 a month back, on average |
| May 2026 | One-month supply true-up after Winter Storm Fern | Supply costs about 50% above April for that month |
| June 2026 | Summer supply price of 10.4¢/kWh; the nuclear credit ended | ComEd estimated $2 to $3 more a month; capacity costs up about $12 a month since 2022 |
| October 2026–May 2027 | Supply price of 10.1¢/kWh | Still well above 2024 levels |
Your exact change depends on your usage and the weather. For each period's price, see the Price to Compare tracker.
What is the capacity auction, and why does it raise my bill?
PJM, the grid operator that serves ComEd, holds an auction each year to pay power plants to be available at the hottest and coldest times. The price for the ComEd region went from $28.92 per megawatt-day for 2024–25 to $269.92 for 2025–26, then hit the auction's price cap of about $329 for 2026–27 and $333 for 2027–28.
The cap is the only thing holding prices down. In the 2028–29 auction, held in July 2026, prices again cleared at the cap; without it, the Chicago region would have cleared at about $777. Grid analysts and the Citizens Utility Board point to fast-growing data center demand as a main driver.
What are the charges on my ComEd bill?
| Section | Line item | What it pays for |
|---|---|---|
| Supply | Electricity Supply Charge | The power itself, passed through at cost |
| Supply | Transmission Services Charge | Moving power over high-voltage lines to ComEd |
| Supply | Purchased Electricity Adjustment | A monthly true-up between the set price and ComEd's actual cost |
| Delivery | Customer Charge and Standard Metering Charge | Fixed monthly fees for billing, service and your meter |
| Delivery | Distribution Facilities Charge | Local poles, wires and their upkeep, per kWh |
| Delivery | Illinois Electricity Distribution Charge | Recovers a state tax on electricity distribution |
| Taxes and other | Energy efficiency, renewable and zero-emission charges | State-required programs and clean energy |
| Taxes and other | Carbon-Free Energy Resource Adjustment | Nuclear support; it becomes a credit when energy prices run high |
| Taxes and other | Franchise cost, state and municipal taxes | Taxes and fees set by your town and the state |
The supply section is usually the largest part of the bill and the part that rose most. It's also the part solar replaces for every kWh your panels produce and you use.
Why is my ComEd bill higher in the summer?
Two reasons stack up. Air conditioning raises how much you use, and ComEd's supply price resets each June 1 with the new capacity year; in summer 2026 it was 10.4¢ per kWh, versus 10.1¢ from October. ComEd also noted that the nuclear credit ending in May made summer 2026 bills higher.
Will ComEd bills keep going up?
- Capacity: the 2028–29 auction also cleared at the cap, so supply prices are likely to stay high through at least May 2029.
- Delivery: ComEd's proposed $15.3 billion grid plan would add about $2.50 to $3 a month starting in 2028 if approved in full. Regulators are expected to decide by the end of 2026.
- State energy law: the 2026 Clean and Reliable Grid Affordability Act adds a charge for grid batteries starting in 2030. The Illinois Power Agency estimates the law lowers bills overall by 2031.
Nobody can promise where prices go, but the forces pushing them up haven't gone away.
How can I lower my ComEd bill?
- Be careful with alternative suppliers. The Citizens Utility Board says ComEd is "probably your best bet" for supply, and warns that many supplier offers cost more.
- Hourly Pricing: ComEd says more than 80% of participants paid less than the fixed rate in 2025. It suits homes that can shift use away from peak hours.
- Time-of-day delivery: ComEd's Delivery Time-of-Day rate charges less overnight. See hourly pricing with solar.
- Budget billing evens out monthly payments but doesn't lower the total.
- Help paying: LIHEAP and ComEd's assistance programs open each fall for households that qualify.
How much would solar cut my ComEd bill?
| Monthly bill | System | Monthly savings, year one | Cost after incentives | Payback |
|---|---|---|---|---|
| $150 | 8.0 kW | $108 | $10,800 | 8.3 yrs |
| $250 | 14.0 kW | $189 | $18,800 | 8.3 yrs |
| $350 | 19.6 kW | $265 | $26,400 | 8.3 yrs |
Solar replaces the supply and per-kWh delivery charges on the power you use as it's produced, and earns a supply-rate credit on what you export. Fixed customer and meter charges stay. Once it's paid for, it also locks in the cost of the power it makes, whatever the capacity auction does next. Enter your bill in the solar savings calculator or see solar with a $250+ bill.
Sources
- Citizens Utility Board: Report on 2026 electric rates
- ElectricityRates.com: ComEd electricity rate increase, June 2025
- Citizens Utility Board: New ComEd electricity price still elevated (October 2025)
- NPR Illinois: Regulators strike millions from Ameren, ComEd electric rate hike requests (December 2025)
- WTTW: ComEd bills see a reduction in April and May thanks to high energy prices and nuclear credits (April 2026)
- Illinois Power Agency: Credits flowing back to ComEd customers (April 2026)
- Citizens Utility Board: Q&A on the May price spike on ComEd bills (April 2026)
- ComEd: Higher PJM supply costs expected to increase customer bills this summer (May 2026)
- Citizens Utility Board: Why is ComEd's price spiking? (June 2026)
- Plug In Illinois (Illinois Commerce Commission): ComEd Price to Compare
- Citizens Utility Board: PJM capacity auction leads to price spike for second straight year (July 2025)
- PJM: 2027/2028 Base Residual Auction report
- Utility Dive: PJM capacity auction clears at price cap again (July 2026)
- Citizens Utility Board: Making sense of your electric bill
- WTTW: ComEd files $15.3 billion grid plan proposal (January 2026)
- WTTW: Pritzker signs major energy reform bill (January 2026)
- Citizens Utility Board: Alternative supplier warning for ComEd customers (June 2026)
- ComEd: Hourly Pricing program reaches record participation (September 2026)
- ComEd: New Delivery Time-of-Day rate (February 2026 announcement)
This guide is general information, not tax, legal or financial advice. Incentive programs change, so confirm current terms with your installer, your utility and a tax professional.