Power Plants in Illinois

Illinois's power sector in numbers

Bywatts maps 158 operating power plants with 40.9 GW of nameplate capacity in Illinois. Natural Gas leads with 36% of that capacity across 50 plants, followed by Nuclear (30%) and Coal (19%). The inventory also includes 74 plants (9.0 GW) that EIA-860 lists as retired, 1 partly retired with no operable units of its recorded fuel and 9 never built; the largest retired plant is JOLIET 29 (1,320 MW, retired 2023).

The largest operating plants are BRAIDWOOD GENERATION STATION (2,450 MW, Nuclear, EXELON NUCLEAR), BYRON GENERATING STATION (2,450 MW, Nuclear, EXELON NUCLEAR) and LASALLE GENERATING STATION (2,340 MW, Nuclear, EXELON NUCLEAR).

Of the 150 operating plants with a recorded commissioning year, 73 came online in 2000 or later and 20 in 2010 or later; the busiest decade for new capacity was the 2000s (13.6 GW).

The largest operators by operating capacity are EXELON NUCLEAR (6 plants, 12.4 GW), UNION ELECTRIC CO (5 plants, 2.4 GW) and MIDWEST GENERATIONS EME LLC (2 plants, 2.1 GW).

Retail electricity sales in Illinois reached 135.4 TWh in 2025, down 2.3% over ten years and up 1.6% year on year; residential customers took 34.4% of it. The average retail price across all sectors was 13.74 cents per kWh, up 46.1% since 2015.

The database also maps 344 named substations (65 of the 65 with a recorded voltage are rated 345 kV or above), 9 data centers (operators include Digital Realty, Equinix and 365 Data Centers), 259 solar installers and 112 solar companies in Illinois.

Operating capacity by fuel

Retail electricity sales

Sources: HIFLD power-plant inventory (capacity, fuel, operator), EIA-860 (commissioning year, retirements, operable capacity), EIA retail sales and revenue series through January 2026. Counts are of plants Bywatts lists, not every generator in the state.