EPA wants new, tougher air controls on Wyoming coal plants

The U.S. Environmental Protection Agency has decided that the state of Wyoming isn’t doing enough to control certain coal-fired emissions, so it is proposing a partial disapproval of a State Implementation Plan (SIP) and a Federal Implementation Plan (FIP) to replace the parts of the SIP that it won’t approve.

EPA said in a June 4 Federal Register notice that it is proposing to only partially approve a SIP revision submitted by the state of Wyoming on Jan. 12 that addresses regional haze needs. EPA said that it is offering the FIP to replace the disapproved parts, but does urge the state to offer new SIP revisions that would equal the FIP. It is taking public comments until Aug. 3, and plans a June 26 public hearing in Cheyenne and a June 28 public hearing in Rock Springs.

EPA is proposing to disapprove the following:

  • The state’s NOx best available retrofit technology (BART) determinations for PacifiCorp’s Dave Johnston Unit 3, Jim Bridger Units 1-2 and Wyodak Unit 1, and Basin Electric’s Laramie River Units 1-3.
  • The state’s NOx reasonable progress determination for Dave Johnston Units 1-2.
  • Wyoming’s Reasonable Progress Goals (RPGs).
  • The state’s monitoring, recordkeeping, and reporting requirements in Chapter 6.4 of the SIP.
  • Portions of the state’s long-term strategy (LTS) that rely on or reflect other aspects of the regional haze SIP.
  • The state’s SIP because it does not contain the necessary provisions to meet the requirements for the coordination of the review of the reasonably attributable visibility impairment (RAVI) and the regional haze LTS.

EPA is proposing to approve the remaining aspects of the state’s Jan. 12 SIP submittal. It is also seeking comment on two alternative proposals related to the state’s NOx BART determination for Jim Bridger Units 1 and 2.

The proposed FIP includes the following elements:

  • NOx BART determinations and limits for Dave Johnston Unit 3, Jim Bridger Units 1-2, Wyodak Unit 1 and Laramie River Units 1-3.
  • NOx reasonable progress determination and limits for PacifiCorp Dave Johnston Units 1-2.
  • RPGs consistent with the SIP limits proposed for approval and the proposed FIP limits.
  • Monitoring, recordkeeping, and reporting requirements applicable to all BART and reasonable progress sources for which there is a SIP or FIP emissions limit.
  • LTS elements pertaining to emission limits and compliance schedules for the proposed BART and reasonable progress FIP emission limits.
  • Provisions to ensure the coordination of the RAVI and regional haze LTS.

EPA’s rules impact several large coal-fired units

Basin Electric’s Laramie River plant is located in Platte County and is comprised of three 550-MW dry-bottom, wall-fired boilers (Units 1-3) burning subbituminous coal. All three units are subject-to-BART.

Dave Johnston is located in Converse County and has four units burning pulverized subbituminous Powder River Basin coal. Units 3 and 4 are the only units subject-to-BART. Dave Johnston Unit 3 is a nominal 230-MW pulverized coal-fired boiler that commenced service in 1964. Dave Johnston Unit 4 is a nominal 330-MW pulverized coal-fired boiler that commenced service in 1972.

Jim Bridger is located in Sweetwater County and has four identically sized nominal 530 MW tangentially fired boilers burning pulverized coal. Jim Bridger Unit 1 was placed in service in 1974, Unit 2 in 1975, Unit 3 in 1976, and Unit 4 in 1979.

Wyodak is located in Campbell County, with Unit 1 burning pulverized subbituminous Powder River Basin coal for a total net generating capacity of a nominal 335 MW. This boiler commenced service in 1978.

As an example of EPA’s problems with some of Wyoming’s findings, EPA said it does not agree with the state’s conclusion that a limit of 0.21 lb/MMBtu for NOx is reasonable for BART for Laramie River Units 1-3, which can be achieved with the installation of low-NOx burners (LNBs) with overfire air (OFA).

Based on its examination of the state’s costs estimates, emission reductions, and the predicted visibility improvement, EPA proposes to find that LNBs with OFA plus selective non-catalytic reduction (SNCR) at an emission limit of 0.12 lb/MMBtu (30-day rolling average) is reasonable for NOx BART for Laramie River Units 1, 2, and 3. EPA said it eliminated the single highest performing option from consideration—LNBs with OFA plus selective catalytic reduction (SCR)—because the cost effectiveness value is significantly higher than LNBs with OFA and there is a comparatively small incremental visibility improvement over LNBs with OFA. EPA proposes that Basin Electric meet the proposed emission limit no later than five years after it finalizes action on the proposed FIP.

Another example is Dave Johnston Unit 3. EPA does not agree with the state’s conclusion that a limit of 0.28 lb/MMBtu is reasonable for NOx BART for Dave Johnston 3, which can be achieved with the installation of LNBs with OFA. EPA proposes to find that LNBs with OFA plus SNCR at an emission limit of 0.19 lb/MMBtu (30-day rolling average) is reasonable for NOX BART. Again, EPA said it did reject a more expensive option that included SCR. It wants compliance with this new limit within five years after approval of the FIP.

EPA noted that the state is not currently aware of any specific scheduled shutdowns, retirements in upcoming years, or replacement schedules, such as planned installation of new control equipment to meet other regulations. If such actions occur, the state will factor them into upcoming reviews.

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.