"In August 2018, the U.S. Environmental Protection Agency (EPA) proposed the 'Affordable Clean Energy' (ACE) rule. ACE would modify provisions for existing power plants under two major Clean Air Act (CAA) programs. Among other things, ACE would 'replace the Clean Power Plan (CPP),' a greenhouse gas (GHG) rulemaking that EPA promulgated under CAA Section 111(d) in 2015. ACE would also modify an applicability determination for New Source Review (NSR), which is a CAA preconstruction permitting program intended to ensure that new and modified stationary sources of air pollution do not significantly degrade air quality. EPA proposed ACE in response to Executive Order 13783, in which President Trump directed federal agencies to 'review existing regulations and policies that potentially burden the development or use of domestically produced energy resources.' Among the order's specific directives was that EPA review the CPP, which was one of the Obama Administration's key actions directed at reducing GHG emissions. EPA's review also led the agency to convene an 'NSR Reform Task Force' to assess opportunities to simplify the NSR application and review process. This report provides background information about the CAA and GHG emissions from the power sector and highlights some of the major components of EPA's ACE proposal. The topics discussed do not represent an exhaustive list of the proposal's elements."
CRS Report for Congress, R45393
Congressional Research Service: https://crsreports.congress.gov/