Power Plants in Illinois

Illinois holds 52.8 gigawatts of nameplate capacity across 652 plants in service as of August 2026, ranking fifth among the 50 states and DC by total fleet size. Natural gas makes up the largest share at 34.4%, followed by nuclear at 23.5%, wind at 16.4%, and coal at 13.9%. Solar accounts for 9.9% of capacity, with the remainder split among other fuels, battery storage, and hydro. The state's generating fleet is measured by the equipment's potential output running flat out; this differs significantly from actual generation, since a megawatt of solar and a megawatt of nuclear produce very different amounts of electricity over a year.

Five nuclear stations dominate the largest plants: Braidwood Generation Station and Byron Generating Station each deliver 2,450 megawatts, LaSalle Generating Station provides 2,340 megawatts, and both Dresden Generating Station and Quad Cities Generating Station each contribute 2,019 megawatts. Natural gas supplies the most plants at 69, while the fleet also includes 458 solar installations, 56 wind plants, and eight coal facilities. The fleet spans a century of technology: Dayton Hydro came online in January 1925, while the newest addition, Allium, entered service in August 2026.