EPA seeks input on changes to air plan for Four Corners coal plant in New Mexico

The U.S. Environmental Protection Agency will in the Dec. 2 Federal Register propose limited revisions to the source-specific Federal Implementation Plan (FIP) that was promulgated to regulate air emissions from the coal-fired Four Corners Power Plant (FCPP), which is located on the reservation lands of the Navajo Nation near Farmington, New Mexico.

These limited revisions propose to make certain provisions of the FIP consistent with national actions and rulemakings promulgated since 2012; to update the FIP to reflect recent operating changes; and to add new provisions to the FIP to include the air pollution control requirements for FCPP of a Consent Decree entered in the U.S. District Court for the District of New Mexico in August 2015.

Any comments on this proposal must be filed within 30 days of Dec. 2. 

The EPA is proposing limited revisions to the FIP for FCPP that it promulgated in May 2007 and August 2012. The EPA established federally enforceable emission limitations for particulate matter (PM), sulfur dioxide (SO2), oxides of nitrogen (NOX), and opacity in the FCPP FIP.

To update the FCPP FIP for consistency with national actions and rulemakings, EPA is proposing to remove:

  • emission limit exemptions that apply during periods of startup and shutdown;
  • a provision allowing for an affirmative defense during periods of malfunctions; and
  • exemptions for water vapor from the opacity standard and monitoring and reporting requirements.

These revisions, if finalized, would make the FCPP FIP consistent with the EPA’s interpretations of Clean Air Act (CAA) requirements, as reflected in the agency’s recent action concerning how provisions in state implementation plans (SIPs) treat excess emissions during startup, shutdown, and malfunctions (called the “2015 SSM Action”).

The EPA is also proposing to update the testing requirements for PM in the FCPP FIP to be consistent with PM testing requirements promulgated nationally in the Mercury and Air Toxics Standards (MATS). The revisions to the PM testing requirements, if finalized, would increase the frequency of PM testing in the FIP to match the MATS Rule, allow the operator the option to demonstrate compliance using alternative methods, e.g., PM continuous emission monitoring systems (PM CEMS), and streamline the existing PM testing requirements.

In order to update the FIP to reflect the current operation of FCPP, EPA is proposing to add a statement to the applicability section of the FIP to clarify that Units 1, 2 and 3 have been permanently retired, and to remove certain provisions related to Units 1, 2, and 3 from the FIP that are no longer applicable following those permanent retirements. The operator of FCPP removed those units from service by Jan. 1, 2014, to comply with the requirements in the 2012 FIP that the EPA promulgated to address the Best Available Retrofit Technology (BART) provisions of the Regional Haze Rule for NOX.

The final changes in this proposed rulemaking are to add new provisions to the FCPP FIP to reflect requirements in the Consent Decree. Generally, the decree requires greater emission reductions of SO2, NOX, and PM by establishing lower emission limitations than the existing limitations in the FIP for these pollutants. The decree requires the operator of the facility to request that the EPA amend the FCPP FIP to incorporate the requirements and limitations from the decree. These proposed revisions, if finalized, would make the emission limitations and other requirements from the decree federally enforceable.

FCPP is a coal-fired plant located on the Navajo Nation Indian Reservation, just west of Farmington, New Mexico, and it is co-owned by several entities and operated by Arizona Public Service (APS). The facility includes two operating units, Units 4 and 5, each with a capacity of 770 MW net generation, providing a total capacity of 1,540 MW. Existing pollution control equipment on Units 4 and 5 include baghouses for PM control, lime spray towers for SO2 control, and low-NOX burners for limiting NOX formation during the combustion process. FCPP is in the process of installing selective catalytic reduction (SCR) on Units 4 and 5 for additional NOX emission reductions to comply with the “better than BART” provisions of the 2012 FIP and with the Consent Decree.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.