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FACT SHEET: Reconsideration of Final Standards

Reciprocating Internal Combustion Engines


  • On August 29, 2013, the U.S. Environmental Protection Agency (EPA) issued a notice announcing reconsideration of, and requesting public comment on, three specific issues in the agency's 2013 final amendments to its standards limiting air pollutant emissions from stationary reciprocating internal combustion engines.
  • EPA is not proposing changes to the 2013 regulations in this notice. The agency is seeking public comment on three issues the agency has agreed to reconsider. The three issues are:
    • timing for compliance with the ultra low sulfur diesel fuel requirement for emergency compression ignition stationary engines that operate for emergency demand response, voltage/frequency deviations or local reliability;
    • timing of and information required for the reporting requirement for emergency stationary engines that operate for emergency demand response, voltage/frequency deviations or local reliability; and
    • conditions for operation of an engine for up to 50 hours per year in non-emergency situations as part of a financial arrangement with another entity.
  • The request for public comment is limited to these three issues.
  • EPA will accept public comment for 60 days after the notice is published in the Federal Register.


  • On January 30, 2013, EPA issued a final rule that amended the agency's 2010 emission standards for stationary reciprocating internal combustion engines.
  • The 2013 amendments established, among other things, fuel and reporting requirements for certain emergency engines used for emergency demand response and system reliability.
  • The 2013 amendments also established conditions under which emergency engines could be used for up to 50 hours per calendar year in situations where an engine is dispatched by the local transmission and distribution system operator to mitigate local transmission and/or distribution limitations in order to prevent the interruption of power supply in a local area or region.
  • EPA received three petitions for reconsideration of the 2013 amendments. The petitions were submitted by:
    • Calpine and PSEG
    • Clean Air Council, PennFuture, Conservation Law Foundation, EDF, NRDC, Pace Energy and Climate Center, Sierra Club and West Harlem Environmental Action
    • Delaware Department of Natural Resources and Environmental Control

Printable version of the fact sheet:

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