Comment period opens on EPA’s ACE rule

By Erin Voegele | September 06, 2018

The U.S. EPA published its proposed rule to create the Affordable Clean Energy Program (ACE rule) in the Federal Register on Aug. 31, officially opening a 60-day public comment period on the proposal.

On Aug. 21, the EPA released a prepublication version of the ACE rule, which aims to establish emissions guidelines for states to develop plans to address greenhouse gas (GHG) emission from existing coal-fired power plants. The ACE rule would replace the Clean Power Plan, which the EPA proposed to repeal last year.

Information released by EPA indicates one major difference between the CPP and the ACE rule is that the CPP promoted disinvestment in coal in favor of renewables and natural gas, and relied on fuel switching. Alternatively, the ACE rule promotes investments to make coal plans cleaner and more efficient and does not promote fuel switching.

According to the EPA, the ACE rule defines the best system of emission reduction (BSER) for existing power plants as on-site, heat-rate efficiency improvements. It also provides states with a list of candidate technologies that can be used to establish standards of performance and be incorporated into their state plans. In addition, ACE updates the new source review (NSR) permitting program to further encourage efficiency improvements at existing power plants and gives states time and flexibility to develop their state plans.

The ACE rule also briefly addresses biomass. While the proposal does not include cofiring as BSER, the agency does propose that biomass cofiring be allowed as a compliance option that states may consider. The rule also references an April 23 April 23 policy announcement by the EPA in which the agency said biomass from managed forests will be treated as carbon neutral when used for energy production at stationary sources.

The public comment period on the ACE rule closes Oct. 30. Comments can be filed online at under EPA-HQ-OAR-2017-0355