US EPA replaces Clean Power Plan with Affordable Clean Energy (ACE) rule

The United States Environmental Protection Agency has issued the final version of the Affordable Clean Energy (ACE) rule, which will replace the previous administration's Clean Power Plan (CPP). The ACE rule sets emission guidelines for states when developing plans to cut CO₂ emissions at their coal-fired power plants and identifies heat rate improvements as the best system of emission reduction (BSER) for CO₂ at coal-fired power plants. States will have three years to submit their emission reduction plans. The EPA expects the ACE rule to cut CO₂ emissions by 11 Mt in 2030, without harming coal-fired power plants that are facing the competition of gas and renewables.

The Clean Power Plan aimed to slash power plant CO₂ emissions by more than a third from 2005 levels by 2030, which would have forced utilities to drop coal in favour of cleaner fuels like natural gas. The regulation was never enacted because of lawsuits by some states and was stayed by the Supreme Court in 2016.