EPA unveils haze proposal for PacifiCorp’s Hunter, Huntington coal plants

The U.S. Environmental Protection Agency is proposing to approve and disapprove parts of Utah’s State Implementation Plan (SIP) for regional haze related to the coal-fired Hunter and Huntington power plants of PacifiCorp.

EPA will publish the proposal in the Jan. 14 Federal Register. It is acting on revisions submitted by the state of Utah in June 2015 and October 2015 to implement the regional haze program. The state’s SIP revisions establish an alternative to best available retrofit technology (BART) controls that would otherwise be required to control NOX at PacifiCorp’s Hunter and Huntington power plants. The June 2015 SIP revision also includes BART determinations for particulate matter with an aerodynamic diameter of less than 10 micrometers (PM10) at these power plants and provisions for making the NOX and PM10 BART emission limits federally enforceable.

The EPA is issuing two co-proposals in order to fully evaluate the state’s submittals and the public’s input on them. The EPA would work with the state on a revised state plan should a partial disapproval and a Federal Implementation Plan (FIP) be finalized.

Written comments on the EPA propoosal must be received within 60 days after the Jan. 14 publication in the Federal Register. A public hearing for this proposal is scheduled to be held on Jan. 26 at the Salt Lake City Public Library.

Co-Proposal 1

Under this co-proposal, EPA is proposing to approve these aspects of the state’s June 2015 SIP submittal:

  • NOX BART Alternative, including NOX emission reductions from Hunter Units 1, 2, and 3, Huntington Units 1 and 2, and Carbon Units 1 and 2, and sulfur dioxide (SO2) and PM10 emission reductions from Carbon Units 1 and 2. (Note that the coal-fired Carbon plant was retired in 2015 by PacifiCorp due to EPA’s Mercury and Air Toxics Standards).
  • BART determinations and emission limits for PM10 at Hunter Units 1 and 2 and Huntington Units 1 and 2.
  • Monitoring, recordkeeping, and reporting requirements for units subject to the BART Alternative and the PM10 emission limits.

EPA is proposing to approve these elements of the state’s October 2015 SIP submittal:

  • Enforceable commitments to revise SIP section XX.D.3.c and state rule R307-150 by March 2018 to clarify emission inventory requirements for tracking compliance with the SO2 milestone and properly accounting for the SO2 emission reductions due to the closure of the Carbon plant.

Co-Proposal 2

Under this co-proposal, EPA is proposing to approve these elements of the state’s SIP submittals:

  • BART determinations and emission limits for PM10 at Hunter Units 1 and 2, and Huntington Units 1 and 2.
  • Monitoring, recordkeeping, and reporting requirements for units subject to the PM10 emission limits.

EPA is proposing to disapprove these aspects of the state’s June 2015 SIP:

  • NOX BART Alternative, including NOX emission reductions from Hunter Units 1, 2, and 3, Huntington Units 1 and 2, and Carbon Units 1 and 2, and SO2 and PM10 emission reductions from Carbon Units 1 and 2.

EPA is proposing to disapprove the state’s October 2015 SIP submittal. It is instead proposing promulgation of a FIP to address the deficiencies in the Utah regional haze SIPs that are identified in this notice. The proposed FIP includes the following elements:

  • NOX BART determinations and emission limits for Hunter Units 1 and 2 and Huntington Units 1 and 2.
  • Monitoring, recordkeeping, and reporting requirements for NOX at Hunter Units 1 and 2, and Huntington Units 1 and 2.

If EPA partially disapproves the SIP, and promulgates a FIP, the state may submit a SIP revision to supersede the FIP. If EPA determines that the SIP revision is approvable, regardless of whether or not its terms match those of the final FIP, it would propose to approve such a SIP revision. If EPA issues a final FIP, it said it encourages the state to submit a SIP revision to replace the FIP.

PacifiCorp’s Hunter plant is located in Castle Dale and consists of three units. Of the three units, only Units 1 and 2 are subject to BART. Hunter Units 1 and 2 have a nameplate generating capacity of 488.3 MW each. The boilers are tangentially fired pulverized coal boilers, burning bituminous coal.

PacifiCorp’s Huntington plant is located in Huntington City and consists of two units. Huntington Units 1 and 2 have a nameplate generating capacity of 498 MW each. The boilers are tangentially fired pulverized coal boilers, burning bituminous coal.

One co-proposal would require costly SCR retrofits

The emissions limits proposed by the state in June 2015 are:

  • Hunter Unit 1, PM10 lbs/mmBtu- 0.015, NOx lbs/mmBtu – 0.26, SO2 limit not applicable;
  • Hunter Unit 2, PM10 lbs/mmBtu- 0.015, NOx lbs/mmBtu – 0.26, SO2 limit not appliable;
  • Hunter Unit 3, PM10 not applicable, NOx lbs/mmBtu – 0.34, SO2 not applicable;
  • Huntington Unit 1, PM10 lbs/mmBtu – 0.015, NOx lbs/mmBtu – 0.26, SO2 not applicable;
  • Huntington Unit 2, PM10 lbs/mmBtu – 0.015, NOx lbs/mmBtu – 0.26, SO2 not applicable;
  • Carbon Unit 1, to be shut by Aug. 15, 2015; and
  • Carbon Unit 2, to be shut by Aug. 15, 2015.

Utah opted to establish an alternative measure for NOX. It compared the Utah BART Alternative against a BART Benchmark of selective catalytic reduction (SCR) on all four BART units at Hunter and Huntington (Units 1 and 2 at both plants). Utah’s BART Alternative consists of the shutdown of Carbon Units 1 and 2 and the installation of upgraded NOX combustion controls (new low-NOX burners (LNB) and overfire air (OFA)) on Hunter Unit 3 (all non-BART units). The Utah BART Alternative also includes the NOX reductions from prior installation of upgraded combustion controls (new LNB and separated overfire air (SOFA)) at Hunter Units 1 and 2 and Huntington Units 1 and 2 (all BART units).

PacifiCorp’s analysis identified three available technologies for PM10: upgraded electrostatic precipitators (ESP) and flue gas conditioning (0.040 lb/MMBtu); polishing fabric filter (0.015 lb/MMBtu); and replacement fabric filter (0.015 lb/MMBtu). A 2008 Utah regional haze SIP and BART determination had required PacifiCorp to install a fabric filter baghouse with a PM10 emission limit of 0.015 lb/MMBtu at the Hunter and Huntington BART units. Utah staff reviewed PacifiCorp’s 2012 analysis and determined that the baghouse technology required in 2008 is still the most stringent technology available and that 0.015 lb/MMBtu represents the most stringent emission limit. Utah cited EPA’s BART Guidelines and regional haze actions in Colorado, Wyoming, North Dakota and Montana to support these assertions.

Utah determined that the PM10 BART emission limit for Hunter Units 1 and 2 and Huntington Units 1 and 2 was 0.015 lb/MMBtu based on a three-run test average. Utah noted that because the most stringent technology is in place at these units and that the PM10 emission limits have been made enforceable in the SIP, no further analysis was required.

Under the co-proposal where EPA would partially disapprove the SIP related to NOx emissions, the federal agency would:

  • require for Hunter Units 1 and 2 the LNB and SOFA controls along with installation of costly selective catalytic reduction (SCR) technology, represented by an emission limit of 0.07 lb/MMBtu (30-day rolling average); and
  • require for Huntington Units 1 and 2 the LNB and SOFA systems along with new SCR controls, represented by an emission limit of 0.07 lb/MMBtu (30-day rolling average).
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.