On September 20, 2013, the United States Environmental Protection Agency (EPA) proposed national limits on carbon dioxide (CO2) emissions for new natural gas-fired stationary combustion turbines and fossil fuel-fired electric utility steam generating units. The proposed rule would establish a “New Source Performance Standard” for CO2 and is known as the “Standards of Performance for Greenhouse Gas Emissions from New Stationary Sources: Electric Utility Generating Units.” The proposed rule is a revision of an earlier EPA rule, now rescinded, which would have established a single standard of 1,000 lb/MWh for both coal and natural gas-fired plants.

Unlike its April 2012 predecessor, the proposed rule adopts separate standards for coal and natural gas-fired plants. New natural gas-fired stationary combustion turbine units over 850 BTU/hr would be subject to a 1,000 lb/MWh emissions limit and those under 850 BTU/hr5 would be subject to a 1,100 lb/MWh limit. Under the proposed rule, new coal-fired plants can either (i) average emissions over an 84-month period if they meet a gross limit between 1,000 to 1,050 lb/MWh6 or (ii) average emissions of 1,100 lb/MWh over a 12-month operating period. The purpose of the longer compliance period is to provide sources with flexibility in phasing in the use of carbon capture and sequestration technologies (CCS).