Regulation Database – New Source Performance Standards for GHG Emissions from Electric Generating Units

The Clean Air Act requires EPA to establish new source performance standards (NSPS) for new and modified stationary emission sources that cause air pollution that may endanger public health or welfare. In December 2010, EPA entered into a settlement agreement to establish NSPS for GHG emissions from  electric generating units.

In April 2012, EPA proposed NSPS for carbon dioxide emissions from new fossil fuel-fired power plants. The proposed standards under section 111(a) of the Clean Air Act were based on the ‘‘best system of emission reduction’’ (BSER) that EPA had determined to be adequately demonstrated for the emissions source. In January 2014, EPA published its withdrawal of the proposal, followed by a new proposed rule with separate standards for modern natural gas plants (combined-cycle) and other facilities, chiefly coal-fired plants. In June 2014, EPA proposed carbon dioxide emission standards for modified and reconstructed power plants. As with new plants, EPA proposed separate standards for gas- and coal-fired facilities.

In October 2015, EPA published a final rule establishing NSPS for carbon dioxide emissions for both new and modified power plants. For new and reconstructed gas-fired plants, under the BSER standard, EPA set the emission limit at 1,000 pounds of CO2 per megawatt‐hour on a gross‐output basis (lb CO2/MWh‐gross). EPA declined to issue standards for modified natural gas plants, based on a need to gather further information. For new coal plants, EPA set the emission limit at 1,400 lb CO2/MWh‐gross, based upon a BSER that would include some carbon capture and sequestration (CCS). For coal plants making larger modifications, EPA set the carbon dioxide emission limit at the level of the facility’s best historical annual performance during the years from 2002 to the time of modification. EPA declined to set NSPS for coal plants making smaller modifications, based in part upon a need to gather further information. For reconstructed coal plants, EPA set the emission limit at 1,800 lb CO2/MWh‐gross for sources with heat input greater than 2,000 MMBtu/h, and 2,000 lb CO2/MWh‐gross for sources with a heat input of less than or equal to 2,000 MMBtu/h.

In conjunction with the NSPS for carbon dioxide emissions from new, modified, and reconstructed power plants, EPA issued separate regulations under section 111(d) of the Clean Air Act applicable to existing power plants.


The NSPS was subsequently challenged in North Dakota v. EPA (2015). One of the key issues in the case is whether partial CCS is an adequately demonstrated technology for reducing GHG emissions from coal-fired power plants. The Sabin Center submitted an amicus brief on behalf of eleven CCS experts asserting that the technology is in fact adequately demonstrated and thus the coal NSPS is lawful.

On March 30, 2017, the  D.C. Circuit Court of Appeals issued an order to delay oral argument and hold the case in abeyance indefinitely. On August 10, 2017, the court issued another order to continue holding the cases in abeyance pending further action from the administration.  As of October 2019, the case is still being held in abeyance. 

Deregulatory Action: 

On March 28, 2017, President Trump issued an executive order instructing EPA to review the new source performance standards and to rescind or rewrite the rule as needed to promote the President’s goals of energy independence and economic growth. EPA immediately  submitted a request to the D.C. Circuit Court of Appeals to hold the North Dakota case in abeyance pending EPA’s reconsideration of the rule.

On April 4, 2017, EPA published a notice in the Federal Register announcing that it is reviewing and, if appropriate will initiate proceedings to suspend, revise or rescind the rule.  On December 6, 2018 EPA proposed revisions that would increase the NSPS to 1,900 pounds of CO2 per MWh for larger units and 2,000 pounds of CO2 per MWh for smaller units.

On January 13, 2021 EPA finalized its revised NSPS for new power plants that abandoned the earlier proposal of increasing the limits on CO2 emissions. However, the final rule contains a new restriction that Section 111 can only be used to regulate greenhouse gases from stationary sources if the source category is responsible for at least 3% of U.S. greenhouse gas emissions. Other sectors that are currently regulated under the Clean Air Act -- such as oil and gas facilities -- could be affected, and the rule could bind the EPA from issuing future greenhouse gas emissions on new stationary sources.


On January 19, 2021, a coalition of states and cities challenged the NSPS and restrictions on future greenhouse gas emissions in the D.C. Circuit. On March 18, 2021, the EPA asked the court to vacate the rule and allow the agency to rewrite it. The court granted this motion on April 5, 2021.

Rule Documents:

Other Documents: