The U.S. Supreme Court has elected to hear a legal dispute over the scope of the authority granted to the Environmental Protection Agency (EPA) under the Clean Air Act to regulate greenhouse gas (GHG) emissions from existing power plants. In orders issued October 29, the Court granted certiorari to four petitioners — West Virginia, North Dakota, the North American Coal Corporation, and Westmoreland Mining Holdings LLC — seeking reversal of a September 2020 D.C. Circuit Court of Appeals decision striking down the Affordable Clean Energy (ACE) rule.