Exelon Generation said Thursday it plans to retire two nuclear power stations in Illinois next year, citing low energy prices and policies that it said favor fossil fuel generation.

U.S. Electricity Generation

The Byron facility outside the city of Byron is to close in September 2021, and the Dresden facility in Morris is set to close in November 2021, the Exelon Corp. subsidiary said. The Dresden plant is licensed to operate for another decade, while Byron could operate another 20 years 

The two plants on the PJM Interconnection power grid supply a combined 30% of Illinois’ carbon-free energy, the company said, and considered “essential” to meeting the state’s 100% clean energy goal.

“Despite being among the most efficient and reliable units in the nation’s nuclear fleet, Dresden and Byron...