US coal retirements would be 50,000 megawatts greater if the Clean Power Plan is implemented.

Coal accounts currently for 33% of US electricity supply. The US Energy Information Administration said in May that coal retirements should be 40,000 megawatts under its base case compared to 90,000 megawatts under the Clean Power Plan, with nearly all the retirements occurring by 2020.

The Clean Power Plan is an effort by the Obama administration to require states to reduce carbon emissions. It is expected to remain tied up in the courts until early 2018. Donald Trump has said he would retract it if elected US president.