Downstate Illinois could be heading for a serious electricity shortage within the next decade.
A new study from three Illinois state agencies warns that the Ameren Illinois region — which serves much of central and southern Illinois and operates within the Midcontinent Independent System Operator, or MISO, power grid — is projected to face capacity shortfalls beginning around 2031, with conditions worsening sharply through 2035.
According to reporting from the Chicago Sun-Times and analysis by Capitol Fax publisher Rich Miller, the problem is being driven by two converging forces: rapidly rising electricity demand — especially from energy-hungry AI data centers — and the continued shutdown of aging coal and natural gas power plants.
The report was conducted by the Illinois Power Agency, the Illinois Environmental Protection Agency, and the Illinois Commerce Commission. It notes that many fossil fuel plants across the MISO region are retiring due to age, cost, and emissions limits, while new power sources are not coming online fast enough to replace them.
In the Ameren territory, state analysts warn that shortages will escalate through the mid-2030s, when peak demand could exceed available supply during extreme heat or cold. Because MISO spans multiple states, Illinois may not be able to rely on imported electricity when neighboring states face the same constraints.
The study identifies massive growth in data center electricity use as the primary driver of increased demand — growth that was not anticipated when Illinois General Assembly passed the Clean Energy Jobs Act (CEJA) in 2021, which set aggressive timelines for cutting fossil fuel emissions.
While renewable energy and battery storage are part of the long-term solution, the report acknowledges those resources face permitting, siting, and transmission challenges. New gas plants, meanwhile, can take five to seven years just to procure equipment, even before construction begins.
As a result, state officials now concede that some fossil fuel plants in downstate Illinois may need to remain online longer than planned to avoid reliability problems.
Lawmakers passed the Clean and Reliable Grid Affordability Act last fall to provide more flexibility on emissions rules and to help keep the grid stable, but another major state study isn’t expected until 2027 — a timeline that business groups say may be too slow.
Governor JB Pritzker’s administration says Illinois can still meet its climate goals while maintaining reliability. But manufacturers, utilities, and grid operators warn that without faster action, downstate Illinois could face higher power prices — or worse.
As one analyst put it: climate goals matter — but if factories shut down or the lights don’t turn on, the pressure to act will be immediate.