A Constellation Energy spokesman says the company’s nuclear power plants haven't been bothered by the heat waves and are expected to provide enough electricity reliably all summer. 

The company was spun off from Exelon and now owns the former Exelon nuclear plants. Brett Nauman says ComEd buys most of Constellation’s electricity in Illinois. That electricity doesn't have far to go. So, the risk of transmission line trouble is minimized for those customers.

Some electric companies are warning they have to get electricity from out of state this year after coal powered plants in Illinois closed. The transmission lines that bring it from other places may reach their peak loads before customers get to peak demand.