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ComEd, Ameren and the supplier market

Commonwealth Edison sold 20.5 TWh to homes in 2024 and Ameren Illinois 5.3 TWh; together they own the wires across most of the state. Illinois allows competitive retail supply, and 80 energy-only providers delivered 62% of all retail electricity — the fifth-highest share among the states — to about 1.7 million accounts; Constellation NewEnergy alone sold about 2 TWh to households. The Illinois Commerce Commission regulates the utilities. Forty-two municipal systems and 26 cooperatives operate outside that market.

A nuclear state

More than half of Illinois’s 2024 generation came from nuclear plants (54%) — Byron Generating Station was the largest producer — with gas at 16%, coal at 15% and wind at 14%. Coal’s share was 43% in 2014. Illinois generated about 185 TWh against 133 TWh of retail sales, exporting the difference.

The residential price rose quickly this year: 19.22¢ per kWh in July 2026 against 17.22¢ a year earlier, an 11.6% increase. Summer cooling drives the electric peak ($193.07 in July 2026). Outages are short — about 59 minutes per customer excluding major events, second only to the District of Columbia.

Gas carries the winter

Gas heats 78% of Illinois homes, and the average gas account used about 898 therms in 2024 — second only to Alaska — at a 2025 price of $1.073 per therm. Rural homes on propane use even more: about 880 gallons a year in the 2020 survey, second-highest among the states, priced at $2.026 a gallon at the close of EIA’s 2025–26 survey. LIHEAP comes through the Office of Community Assistance at the Department of Commerce and Economic Opportunity.