Exelon is threatening to shutter three nuclear plants in northern Illinois, which together power the equivalent of 5.5 million homes in the region.

The Chicago-based parent of Commonwealth Edison and the largest nuclear power generator in the country issued the warning about the potential for “early retirement” of its Byron, Dresden and Braidwood nuclear stations in a February 8th Securities & Exchange Commission filing.

From Crain's Chicago Business:

“Dresden, Byron, and Braidwood nuclear plants in Illinois are … showing increased signs of economic distress, which could lead to an early retirement, in a market that does not currently compensate them for their unique contribution to grid resiliency and their ability to produce large amounts of energy without carbon and air pollution,” Exelon said in the filing. The earliest Exelon could move to close Byron and Braidwood is mid-2022. Those plants have committed with PJM Interconnection, which is responsible for managing wholesale power markets in all or part of 13 states and the District of Columbia from Illinois east to the mid-Atlantic, to operate until then.

Exelon offered a statement to Crain's, saying: “We are working with Illinois policymakers and other stakeholders on solutions to not only maintain Illinois’ clean energy progress but to further advance efforts to reduce and eliminate carbon emissions in the electric power and other sectors.”