Earlier this month, the US EPA unveiled its plan to roll back the limits on greenhouse gas emissions from power plants, which will give states more control over setting the limits for carbon dioxide regulation. According to the proposal, a new plan, entitled the Affordable Clean Energy (ACE) rule, will replace the Clean Power Plan (CPP), which was established in fall 2015.

The EPA stated that its repeal of the CPP was because the Best System of Emission Reduction (BSER) of the CPP “exceeded the EPA’s authority” by applying measures to the power sector as a whole instead of to individual facilities. The proposal stated that as per the EPA’s statutory authority, BSER is to be “applicable to, at and on the premises of the facility for an affected source.”

The proposal stated that coal-fired power plants can reduce their carbon dioxide emissions by making efficiency upgrades, which limit the amount of carbon dioxide that is emitted per unit of electricity generated. Certain technologies would contribute to these efficiency upgrades, according to the EPA, which listed the following “candidate” technologies: neural network/intelligent sootblowers; boiler feed pumps; air heater and duct leakage control; variable frequency drives; blade path upgrade (steam turbine); redesigning/replacing economizers; and improved operations and maintenance practices. It is up to states to determine which of these technologies will be applicable and appropriate at each power plant, and to establish their own levels of greenhouse emission reduction from their application.

The EPA claims that in certain situation the ACE rule will save up to $6.4 billion compared to the CPP. Nearly 600 coal-fired electric generating units at 300 facilities may be covered by the ACE rule. The EPA is accepting comments regarding the ACE proposal for 60 days.