Greenhouse Gases Focus
The U.S. Environmental Protection Agency (EPA) today announced that it will not further revise greenhouse gas (GHG) permitting thresholds under the Clean Air Act. Today’s final rule is part of EPA’s common-sense, phased-in approach to GHG permitting under the Clean Air Act, announced in 2010 and recently upheld by the U.S. Court of Appeals for the D.C. Circuit. The final rule maintains a focus on the nation’s largest emitters that account for nearly 70 percent of the total GHG pollution from stationary sources, while shielding smaller emitters from permitting requirements. EPA is also finalizing a provision that allows companies to set plant-wide emissions limits for GHGs, streamlining the permitting process, increasing flexibilities and reducing permitting burdens on state and local authorities and large industrial emitters.
A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. In the Solar System, the atmospheres of Venus, Mars, and Titan also contain gases that cause greenhouse effects. Greenhouse gases greatly affect the temperature of the Earth; without them, Earth's surface would be on average about 33 °C (59 °F)colder than at present.
Since the beginning of the Industrial Revolution, CO2 atmospheric concentration has increased from 280 to near 400 ppm due to the combustion of fossil fuels.
After consulting with the states and evaluating the phase-in process, EPA believes that current conditions do not suggest that EPA should lower the permitting thresholds. Therefore, EPA will not include additional, smaller sources in the permitting program at this time.
The final rule affirms that new facilities with GHG emissions of at least 100,000 tons per year (tpy) carbon dioxide equivalent (CO2e) will continue to be required to obtain Prevention of Significant Deterioration (PSD) permits. Existing facilities that emit 100,000 tpy of CO2e and make changes increasing the GHG emissions by at least 75,000 tpy of CO2e, must also obtain PSD permits. Facilities that must obtain a PSD permit, to include other regulated pollutants, must also address GHG emission increases of 75,000 tpy or more of CO2e. New and existing sources with GHG emissions above 100,000 tpy CO2e must also obtain operating permits.
EPA’s GHG permitting program follows the same Clean Air Act process that states and industry have followed for decades to help ensure that new or modified facilities are meeting requirements to protect air quality and public health from harmful pollutants. As of May 21, 2012, EPA and state permitting authorities have issued 44 PSD permits addressing GHG emissions. These permits have required new facilities, and existing facilities that make major modifications, to implement energy efficiency measures to reduce their GHG emissions.
Chart of GHG Sources image via EPA.