Clean Air Markets
Affected Units Figures
Source: EPA, 2017
Last updated: 05/2017
Acid Rain Program (ARP)
- In 2015, the ARP SO₂ requirements applied to 3,520 fossil fuel-fired combustion units at 1,226 facilities across the country; 795 units at 336 facilities were subject to the ARP NOₓ program.
Cross-State Air Pollution Rule (CSAPR)
- In 2015, there were 2,820 affected EGUs at 864 facilities in the CSAPR SO₂ program. Of those, 2,225 (79 percent) were also covered by the ARP.
- In 2015, there were 2,820 affected EGUs at 864 facilities in the CSAPR NOₓ annual program and 3,228 affected EGUs at 946 facilities in CSAPR NOₓ ozone season program. Of those, 2,225 (79 percent) and 2,552 (79 percent), respectively, were also covered by the ARP.
Analysis and Background Information
In general, the ARP and CSAPR SO₂, NOₓ annual, and NOₓ ozone season trading programs apply to large EGUs—boilers, turbines, and combined cycle units– that burn fossil fuel, serve generators with nameplate capacity greater than 25 megawatts, and produce electricity for sale. These EGUs include a range of unit types, including units that operated year-round to provide baseload power to the electric grid, as well as units that provided power only on peak demand days. The ARP NOₓ program applies to ARP-affected units that are older coal-fired boilers.