Approval and Promulgation of Air Quality Implementation Plans; Wyoming; Regional Haze Federal Implementation Plan
Key claim: The EPA is proposing to revise Wyoming’s regional haze Federal Implementation Plan by withdrawing and updating the NOx BART requirements for PacifiCorp’s Dave Johnston Power Plant Unit 3 after the operator withdrew consent to closure.
Abstract
(Proposed Rule · Environmental Protection Agency) The U.S. Environmental Protection Agency (EPA) is proposing revisions to the Federal Implementation Plan (FIP) addressing regional haze in the State of Wyoming. The EPA is proposing revisions to the FIP’s nitrogen oxides (NOX) best available retrofit technology (BART) requirements for the PacifiCorp Dave Johnston Power Plant Unit 3. In response to PacifiCorp’s letter no longer consenting to closure of Dave Johnston Unit 3, the EPA is proposing to withdraw the NOX BART determination containing the closure requirement. Additionally, in response to a request from PacifiCorp, and in light of new information that was not available at the time the EPA originally promulgated the FIP in 2014, the Agency is also proposing to revise the other NOX BART determination for Dave Johnston Unit 3.
Why this matters
Regional haze BART determinations directly shape NOx control costs and operating decisions at aging coal units, and this action illustrates how FIP requirements can be reopened when operators reverse prior closure commitments. The revised limits will affect PacifiCorp’s compliance investment at Dave Johnston Unit 3 and visibility outcomes at downwind Class I areas, while signaling EPA’s approach to updating decade-old FIPs when underlying assumptions change.