On August 31, 2018, the U.S. Environmental Protection Agency (EPA) published a proposal to replace the Clean Power Plan (CPP) and revise implementation regulations and the New Source Review (NSR) program. Titled Emission Guidelines for Greenhouse Gas Emissions from Existing Electric Utility Generating Units; Revisions to Emission Guideline Implementing Regulations; Revisions to New Source Review Program (Proposed Rule) or the Affordable Clean Energy (ACE) Rule, the Proposed Rule includes three actions:
1. EPA proposes to replace the Clean Power Plan (CPP) with revised emission guidelines based on an analysis of heat rate improvements (HRIs) at coal-fired electric generating units (EGUs).
2. EPA proposes new regulations for this and future actions under Clean Air Act (CAA) section 111(d) that provide direction to EPA and states on the implementation of emission guidelines.
3. EPA proposes revisions to the New Source Review (NSR) program that are intended to address potential barriers to the implementation of HRI projects at EGUs.