Ameren Illinois Electric Rates: Price to Compare, Bill Calculator and Every Charge

Ameren Illinois is the electric utility for most of central and southern Illinois. Ameren Missouri, across the river, is another utility whose prices are set by the Missouri Public Service Commission, and Ameren’s gas rates are not covered here. Ameren Illinois’s official tariffs are on its Illinois electric rates page, and the state’s comparison of supplier offers is at Plug In Illinois.

Your bill, line by line

Type your kWh and the billing month printed on your bill; every month back to June 2025 is here, each with the charges Ameren set for it. If a supplier or your town’s programme sells you power, choose that and type the contract price: the four supply lines give way to it, and nothing else on the bill moves. Two inputs are optional. Town tax varies from one town to the next, and the PBR delivery adjustment is a percentage printed on your bill but not on Ameren’s rate pages. Our appliance cost calculator shows which devices use the kWh.

Where 800 kWh goes

Ameren’s delivery comes to $53.17 on the November 2026 bill: a customer charge of $8.04 (the DS-1 charge of $7.42 plus four small state and Ameren adders), a meter charge of $5.96, the distribution charge, the cost of collecting the state’s electricity distribution tax, and a net 3.10% in percentage adjustments on all of those. Supply and transmission come to $85.63, or 56% of the total. The rest, $13.10, is state programme charges, the customer generation charge and the state excise tax.

Only the supply side changes if you switch. A supplier or town programme takes over the BGS-1 supply charge, the purchased electricity adjustment, the two supply cost adjustments and transmission. Ameren still delivers the power and bills for delivery, and the state charges stay on whoever supplies it.

Delivery: customer, meter, distribution and EDT charges with the percentage adjustments (PBR adjustment not included). Supply: BGS-1, the purchased electricity adjustment and both supply cost adjustments. Riders: the per-kWh state programme charges and the customer generation charge.

Ameren’s supply price, month by month

From January 2017 until the summer of 2021, Ameren’s Price to Compare never reached 7¢. In June 2022 the summer price jumped to 10.628¢, against 4.821¢ the July before. It eased to around 8¢ for the summers of 2023 and 2024, then rose to 12.180¢ in 2025 and was 11.326¢ in 2026. October brings the non-summer price, with a lower rate for every kWh above 800, which helps homes that heat with electricity.

One supply line sits outside the Price to Compare: the purchased electricity adjustment, which squares what Ameren collected for supply against what the supply cost. It is set each month and applies only to homes on Ameren’s supply. From June 2017 to November 2025 it was smaller than half a cent, either way, in all but one month. Then December 2025 bills got 4.996¢ back on every kWh, which took $39.97 off an 800 kWh month. The orange line in the chart adds it to each month’s price.

Why summer costs more

Two things make a June to September bill dearer. Delivery has one summer distribution rate, 7.811¢ a kWh in 2026, where October to May charges 4.572¢ for the first 800 kWh and 2.427¢ above. And supply is priced higher in summer, when the grid needs the most power plants. Part of the supply price is capacity: what Ameren pays to have enough generating capacity standing by. Ameren’s June sheet each year states that cost. For summer 2025 it was $666.50 per MW-day, about 22 times the $30.00 of summer 2024. That year the July Price to Compare rose by about 4¢. For summer 2026 the capacity cost was $424.30.

Capacity: the Rider HSS “capacity cost” in Ameren’s June informational sheet each year, in dollars per kW of peak load per day, shown here per MW. Until 2022 MISO set one capacity price for the year; from 2023 it sets one per season, and the table shows the summer price (June to August). Price to Compare: ICC and Ameren, as in the chart above.

Checking a supplier’s offer

In 2025, 45% of Ameren Illinois homes bought their power from a supplier or a town programme rather than from Ameren. An offer saves money only if its price beats everything it replaces: Ameren’s supply charge, the monthly adjustment, both supply cost adjustments and transmission. The table below runs a fixed price against what those lines cost over the last 12 billing months at your use. Put in the offer’s price and any monthly fee. Before signing, read how long the contract runs, whether leaving early costs a fee, and which price applies once the term is over.

Delivery charges set to 2027

A multi-year rate plan fixes Ameren’s delivery charges through 2027, and the charges for each calendar year are on file in the Rate PBR-R appendix. On 1 January 2027 the customer charge goes to $8.50, the meter charge to $6.36, and summer distribution to 8.009¢ a kWh. A reconciliation each year can add or take away a percentage on top: that is the PBR delivery adjustment on bills, which the calculator leaves at zero unless you enter it.

Rate PBR-R appendix, sheet 8.011 (6th revised), filed 21 August 2025 under ICC Docket 25-0083, effective for each year’s billing periods. Before the percentage adjustments.

1. Every monthA new purchased electricity adjustment, on Ameren’s monthly sheet; sometimes a change in a percentage rider.
2. 1 JanuaryThe next year’s delivery charges from the table above, a new transmission charge, and new energy efficiency, energy transition, customer generation and revenue balancing charges.
3. 1 JuneSummer supply prices and a new transmission charge; Rider EUA and the clean energy assistance charge reset.
4. 1 SeptemberThe clean energy assistance charge resets again.
5. 1 OctoberNon-summer supply prices, with the cheaper step above 800 kWh.

Every rider on the bill

Riders are the charges that sit outside the base rates, each with its own tariff sheet and its own reset date. Four are charged per kWh and add 1.269¢ together this month; three are percentages of base delivery; the rest are folded into the customer charge. Every one applies to supplier customers too. Power Smart Pricing, Ameren’s hourly-price option, is not modelled in the calculator.

What Ameren homes paid since 1990

The EIA figure divides residential revenue by residential kWh, so it blends every line of the bill. Before October 2010 the figures add up the three companies that merged to form Ameren Illinois: Central Illinois Public Service, Central Illinois Light and Illinois Power. From 1999 to 2006, while Illinois froze rates after opening the market to competition, homes paid between 7.4¢ and 8¢ a kWh. When the freeze ended in 2007 the price went to 10.6¢ and then stayed between about 9¢ and 10.7¢ until 2020. The biggest rise in the series came in 2022, from 11.2¢ to 15.4¢. It reached 17.0¢ in 2023, fell to 15.3¢ in 2024 and was 16.7¢ in 2025. Over the year to August 2026, homes on Ameren’s supply averaged 17.4¢, up 79.2% on 1990.

Against other Illinois utilities

Ameren Illinois and ComEd between them serve most Illinois homes: ComEd the north, Ameren the centre and south. Municipal utilities and co-operatives serve the rest. For November 2026 ComEd’s Price to Compare is 10.103¢. By EIA’s home price, Ameren Illinois ranks 26th in our table of the 40 largest. See Illinois electricity rates for the state as a whole.

EIA-861, 2025, homes buying their power from the utility itself. A year’s average, so the figure for this utility can differ a little from the 12 months above.

Outages

Ameren Illinois customers averaged 287 minutes without electricity in 2025, and 130 minutes once the largest events are set aside. The worst year it has reported to EIA was 592 minutes in 2023.

Rooftop solar

EIA counted 39,801 Ameren Illinois net-metered solar customers in 2025, 3.7% of the homes it serves; their panels add up to 438 MW. Every bill now pays a monthly customer generation charge under Rider CGC, $0.31 a month in 2026; it is in the rider table above.

EIA-861 Net Metering: homes with solar panels on a net-metering arrangement at the end of each year.

Where Ameren Illinois serves

Ameren Illinois delivers electricity to 1.1 million homes across central and southern Illinois, including Peoria, Champaign-Urbana, Decatur, Bloomington and the Metro East around East St. Louis. The county list is the one Ameren reports to EIA. Some towns in those counties run their own electric utility; Springfield’s is City Water, Light and Power.

EIA-861 Service Territory, 2025. A county on the list may be served only in part, and other utilities may serve the same county.

How the figures were checked

A script pulls each number here from Ameren’s documents, and the build halts when any check fails. Supply comes from Ameren’s monthly informational sheet for Riders BGS, PER and HSS. There are 74 such sheets with machine-readable text, from January 2020 on; 52 older sheets back to June 2016 are scanned images, and for those months we use the Illinois Commerce Commission’s Price to Compare table. Where the two overlap, the script checks every month’s Price to Compare against the sum of its parts. In 5 months the ICC table differs from Ameren’s sheet, in three by a sign or a decimal place, and the page uses Ameren’s figure. Transmission matches every Rider TS sheet we hold.

Delivery charges come from the Rate PBR-R appendix. Its sheet is an image, so we read the figures by hand, and the script checks them against Ameren’s own net metering sample bill. That bill, at July 2025 charges, is rebuilt line by line to the cent, apart from the customer charge, whose adders the sample does not break out. Our server, the in-page calculator and our script share one formula, and on 3,000 test bills they agreed on every line to the cent.

One gap is open. Rebuilt for June to December 2025 at EIA’s average use each month, our bills before tax come to 19.4¢ a kWh, against 17.3¢ in EIA’s figures for homes on Ameren’s supply over the same months. EIA’s months also do not line up with Ameren’s billing months: its summer prices run on into October. We have not found the cause, so the page shows both figures rather than adjusting either. Not modelled: the PBR delivery adjustment (enter it from your bill), town taxes, Rider EEA, which applies only in some former rate zones, Power Smart Pricing, net metering credits and bills that span two months. Carbon uses the EPA eGRID SERC Midwest average: an average for the region, which says nothing about a given supplier’s sources.

Questions

Download the data

• Ameren Illinois, every month (CSV)
• All 40 utilities, latest figures (CSV)
• Citable archive on Zenodo (DOI 10.5281/zenodo.24071582): all 40 utilities, with field descriptions
• Dataset, code and history on GitHub

How to cite this page

@dataset{say2026amerenillinoisel,
  author    = {Say, Jeremiah},
  title     = {Ameren Illinois electricity rates: monthly residential price since 1990},
  year      = {2026},
  publisher = {GreenCalculus},
  doi       = {10.5281/zenodo.24071582},
  url       = {https://doi.org/10.5281/zenodo.24071582}
}

Version history

• 1.0 (13 November 2026): first version. Supply from Ameren’s informational sheets through November 2026; delivery from the Rate PBR-R appendix filed 21 August 2025.