Electricity in St. Clair County, Illinois
4 electric utilities serve homes in St. Clair County, Illinois: Ameren Illinois, Southwestern Electric Cooperative, Tri-County Electric Cooperative and Egyptian Electric Cooperative Association. In 2025, the average home bill of these utilities was $148.32 (Ameren Illinois) to $200.77 (Tri-County Electric Cooperative) a month. This page covers 2 cities with 25,000 or more people in the county, from Belleville to O'Fallon.
- 2 cities
- 4 utilities
- EIA and Census data, 2025
Electric utilities in St. Clair County
EIA lists utilities by county, not by address. Your address has one utility: its name is on your bill, or type your ZIP code in the utility finder.
| Utility | Homes in Illinois | Average bill 2025 | 1,000 kWh now |
|---|---|---|---|
| Ameren IllinoisInvestor-owned utility · bill calculator | 1,062,810 | $148.32888 kWh, 16.7¢ | $176.29 |
| Southwestern Electric CooperativeElectric cooperative | 24,414 | $178.241,160 kWh, 15.4¢ | — |
| Tri-County Electric CooperativeElectric cooperative | 16,203 | $200.771,241 kWh, 16.2¢ | — |
| Egyptian Electric Cooperative AssociationElectric cooperative | 13,695 | $195.841,208 kWh, 16.2¢ | — |
5 smaller utilities with fewer than 1,000 homes are also listed in the county. The average bill is the 2025 average of each utility's homes that bought their power from it (EIA-861). The Illinois average was $126.59 a month.
Cities in St. Clair County
| City | People | City-owned utility | Solar kWh a year per kW |
|---|---|---|---|
| Belleville | 40,237 | — | 1,397 |
| O'Fallon | 32,656 | — | 1,390 |
A city-owned utility is a municipal utility in the county with the city's name (EIA data). Solar output: PVWatts version 8 for a south-facing roof; see the solar savings calculator.
More about Illinois: Illinois electric rates, all Illinois utilities, home energy rebates and natural gas bills.
Who provides electricity in St. Clair County?
4 electric utilities serve homes in St. The name of your utility is on your bill.
Which cities in St. Clair County are on this page?
Belleville and O'Fallon.
Sources: EIA-861 data, 2025 (utilities by county, homes and average bills); Census Bureau city population estimates, Vintage 2025; PVWatts (National Laboratory of the Rockies).