EPA’s long-awaited proposal would set aggressive emission reduction targets with many different approaches and timelines to achieve them.

By Stacey L. VanBelleghem and Jennifer Garlock

On May 11, 2023, the US Environmental Protection Agency (EPA) released its proposed rule[1] to regulate carbon dioxide (CO2) emissions from electric generating units (EGUs) at power plants under Section 111 of the Clean Air Act (CAA) (the Power Plant GHG Rule or the Proposed Rule).

The Power Plant GHG Rule consists of five proposed actions:

  1. determinations and updates to current CO2 standards of performance (promulgated in 2015) for new and reconstructed stationary combustion turbines (generally natural gas-fired) pursuant to Section 111(b) of the CAA;
  2. determinations and updates to current CO2 standards of performance (promulgated in 2015) for modified fossil fuel-fired steam-generating EGUs (generally coal-fired) pursuant to Section 111(b) of the CAA;
  3. determinations and CO2 emission guidelines for existing fossil fuel-fired steam-generating EGUs (generally coal-fired) pursuant to Section 111(d) of the CAA;
  4. determinations and CO2 emission guidelines for large, frequently used existing fossil fuel-fired stationary combustion turbines (generally natural gas-fired) pursuant to Section 111(d) of the CAA; and
  5. a repeal of the Trump-era Affordable Clean Energy (ACE) Rule.

EPA is also soliciting comment on a number of topics, including potential options and emission guidelines for existing fossil fuel-fired stationary combustion turbines not otherwise covered by the Proposed Rule (generally natural gas-fired units that are either smaller or less frequently used).