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Clean Air Markets

Progress Report

Affected Units

Affected Units Figures

Last updated: 05/2016

Related Figures

Affected Units in CAIR and ARP Programs, 2014
Table of Affected Units in CAIR and ARP, 2014

Key Points

Acid Rain Program (ARP)

  • In 2014, the ARP SO₂ requirements applied to 3,597 fossil fuel-fired combustion units at 1,239 facilities across the country; 845 units at 351 facilities were subject to the ARP NOₓ program.

Clean Air Interstate Rule (CAIR)

  • In 2014, there were 3,199 affected EGUs at 926 facilities in the CAIR SO₂ program. Of those, 2,529 (79 percent) were also covered by the ARP.
  • In 2014, there were 3,199 affected EGUs at 926 facilities in the CAIR NOₓ annual program and 3,126 EGUs and industrial units at 914 facilities in the CAIR NOₓ ozone season program.

Analysis and Background Information

The ARP affects EGUs with an output capacity greater than 25 megawatts that burn coal, oil, or gas, as well as all new EGUs. The ARP NOₓ program affects boilers mostly at coal-fired power plants.

The CAIR SO₂ and NOₓ annual programs generally applied to large EGUs that burned fossil fuels to generate electricity for sale. EGUs in the CAIR programs covered 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.

In addition to including large EGUs that generated electricity for sale, the CAIR NOₓ ozone season program included some other fossil fuel-fired facilities that were carried over from the NBP. Such facilities may include large industrial units, such as boilers and turbines at heavy manufacturing facilities (including paper mills, petroleum refineries, and iron and steel production facilities). These units also included some fossil fuel-fired steam plants at institutions such as large universities or hospitals.

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