The U.S. Environmental Protection Agency (EPA), on April 13, 2012, promulgated proposed new source performance standards (NSPS) to limit carbon dioxide (CO2) emissions from new electric-generating units (EGUs) greater than 25 megawatt electric (MWe) located in the continental United States.1 The standards are based on the emissions produced by a natural gas combined- cycle (NGCC) facility. EPA does not expect any coal-fired EGU to meet this standard without utilizing carbon capture and storage (CCS) technology to prevent 50% or more of the CO2 emissions from being released to the atmosphere. This proposed rule is the latest effort by EPA to deal with a dilemma created by the U.S. Supreme Court when, in April 2007, the Court held that greenhouse gases (GHGs) were air pollutants under the Clean Air Act (CAA).