On July 8, 2019, U.S. EPA published the final Affordable Clean Energy (ACE) Rule that became effective September 6, 2019. The ACE Rule establishes emission guidelines for states to use when
developing plans to limit carbon dioxide (CO2) at coal-fired electric generating units (EGUs). In this notice, U.S. EPA also repealed the Clean Power Plan and issued new implementing
regulations for ACE and future rules under section 111(d).
For more information, please see the U.S. EPA's Affordable Clean Energy Rule.
On January 19, 2021, the D.C. Circuit vacated the Affordable Clean Energy Rule and remanded it to the U.S. Environmental Protection Agency (EPA) for further proceedings consistent with its opinion.
On February 12, 2021, the U.S. EPA issued a "Status of Affordable Clean Energy Rule and Clean Power Plan" memorandum stating that U.S. EPA does not expect states to take any further action to
develop and submit plans under the Clean Air Act section 111(d) with respect to greenhouse gas emissions from power plants at this time.