Ameren Illinois Company
Investor Owned electric utility · Illinois · #58 of 3,199 U.S. utilities by customers · EIA utility #56697
Ameren Illinois Company is a investor owned electric utility serving 663,709 customers in Illinois. In 2025 it sold 9,490 gigawatt-hours of electricity for $1.47B in revenue, an average realized rate of 15.51¢ per kWh across all customer classes and 16.70¢ per kWh for residential customers. Its reported service territory covers 81 counties. EIA records its activities as: transmission, buying transmission, distribution, bundled.
Customers, sales and rates by customer class (2025)
| Class | Customers | Sales (GWh) | Revenue | Avg realized rate | Share of sales |
|---|---|---|---|---|---|
| Residential | 587,659 | 6,262 | $1.05B | 16.70¢ | |
| Commercial | 75,726 | 2,570 | $375.34M | 14.60¢ | |
| Industrial | 323 | 644 | $49.12M | 7.63¢ | |
| Transportation | 1 | 14.4 | $1.73M | 11.98¢ | |
| Total | 663,709 | 9,490 | $1.47B | 15.51¢ |
Average realized rate = revenue divided by sales as reported on EIA Form 861. It blends fixed charges, demand charges and riders into one per-kWh figure; it is not the utility's tariff rate. Estimated residential bill assumes the average residential customer's actual 2025 usage (888 kWh/month).
Five-year trend
| Year | Customers | Sales (GWh) | Revenue | Residential rate |
|---|---|---|---|---|
| 2021 | 494,307 | 7,849 | $826.53M | 11.17¢ |
| 2022 | 606,549 | 9,675 | $1.43B | 15.37¢ |
| 2023 | 691,223 | 9,176 | $1.49B | 17.04¢ |
| 2024 | 588,544 | 8,282 | $1.15B | 15.26¢ |
| 2025 | 663,709 | 9,490 | $1.47B | 16.70¢ |
Reliability (2025)
Average outage time (SAIDI): 287 minutes per customer per year
Average outages (SAIFI): 1.19 per customer
Average restoration time (CAIDI): 242 minutes
As reported for Illinois under the IEEE standard, with major event days included where the standard reports them. Lower is better; see the reliability rankings.
Energy supply (2025)
Net generation: 6.5 GWh
Wholesale power purchased: 10,146 GWh
Winter peak demand: 6,888 MW
Energy losses: 1.4% of energy handled
Meters & rooftop solar (2025)
Smart (AMI) meters: 99.9% of 1,221,809 meters
Customer-sited generation (net metering): 62,239 installations, 959.5 MW of capacity
This utility also reported 566,231 delivery-only customers (24,184 GWh delivered) in 2025. Delivery figures are excluded from the totals above because the same electricity is also reported by the energy supplier - see Methodology.
Counties served
Adams, ILAlexander, ILBond, ILBrown, ILBureau, ILCalhoun, ILCass, ILChampaign, ILChristian, ILClark, ILClay, ILClinton, ILColes, ILCrawford, ILCumberland, ILDeWitt, ILDouglas, ILEdgar, ILEdwards, ILEffingham, ILFayette, ILFord, ILFranklin, ILFulton, ILGallatin, ILGreene, ILHancock, ILHenderson, ILHenry, ILIroquois, ILJackson, ILJasper, ILJefferson, ILJersey, ILJohnson, ILKendall, ILKnox, ILLaSalle, ILLawrence, ILLivingston, ILLogan, ILMacon, ILMacoupin, ILMadison, ILMarion, ILMarshall, ILMason, ILMassac, ILMcDonough, ILMcLean, ILMenard, ILMercer, ILMonroe, ILMontgomery, ILMorgan, ILMoultrie, ILPeoria, ILPerry, ILPiatt, ILPike, IL + 21 more counties
Other large utilities in Illinois
- Commonwealth Edison Co - 3,261,563 customers, residential 17.71¢
- MC Squared Energy Services, LLC - 293,923 customers, residential 8.14¢
- Homefield Energy - 160,102 customers, residential 10.64¢
- Energy Services Providers, Inc - 90,477 customers, residential 13.01¢
- Just Energy Solutions Inc. - 80,538 customers, residential 11.33¢
- City of Springfield - (IL) - 70,871 customers, residential 13.09¢
- Residents Energy, LLC - 69,834 customers, residential 17.34¢
- City of Naperville - (IL) - 64,025 customers, residential 14.61¢
All Illinois utilities and rates
Source: U.S. Energy Information Administration, Form EIA-861 2025 (filed by the utility; figures as published). Utility #56697 in the EIA frame.