Three Wyoming coal-fired power plants will be required to install costly controls to curb nitrogen oxide (NOx) emissions under a regional haze rule that was finalized by the Environmental Protection Agency (EPA) last week.
The agency disapproved parts of a state implementation plan (SIP) submitted by Wyoming in January 2011 to address regional haze. It did, however, approve several aspects of the SIP initially disapproved in a June 2013 proposed rule in light of public comments and “newly available information.”
It means that out of the state’s 15 coal units subject to regional haze requirements, at least 10 can use NOx emission control technology as deemed appropriate by the state. However, PacifiCorp’s Dave Johnston Unit 3 and Wyodak Unit 1, and Basin Electric Laramie River Units 1, 2, and 3 are now required to install new low-NOx burners with overfire air and Selective Catalytic Reduction (SCR) controls. The rule gives Dave Johnston Unit 3 the option to shut down in 2027 if it chooses not to install SCR controls. EPA estimated capital costs for the controls range from $16 million (for Dave Johnston, with SCR) to $188.8 million (for Laramie River Unit 2).
The EPA said the use of SCR controls has grown ten-fold to about 130,000 MW of coal capacity (or over 40% of all U.S. coal capacity), compared to just 13,000 MW in 2002.
The agency entered into a consent decree to issue a final regional haze rule for Wyoming by Jan. 10, 2014, after it was sued by environmental groups for its failure to take timely action with respect to the regional haze requirements.
Regional haze is visibility impairment produced by several sources across a broad area that emit fine particles and their precursors: sulfur dioxide, NOx, and in some cases, ammonia, and volatile organic compounds.
The regional haze program, adopted as part of 1990 Clean Air Act amendments, is designed to improve visibility in national parks and wilderness areas. States are delegated authority to develop SIPs to demonstrate reasonable progress towards restoring visibility levels.
Last July, the U.S. Court of Appeals for the 10th Circuit upheld the EPA’s rejection of Oklahoma’s SIP, saying that while the legislative history of the regional haze program shows that Congress intended to prevent the EPA from directly determining BART, it “does not necessarily evidence an intent to deprive the EPA of any authority to ensure that these BART decisions comply with the statute.”
In September, the Eighth Circuit also upheld the EPA’s authority to reject North Dakota’s SIP. The court, however, remanded EPA’s own federal implementation plan (FIP) for its failure to consider a certain coal-drying technology unique to the facility.
That month, the Ninth Circuit denied a request to delay installing pollution controls at three large-coal power plants in Arizona. Later in December, the D.C. Circuit rejected the state’s appeal challenging a court-ordered deadline for plans to reduce haze pollution in the state. Arizona is legally contending the EPA’s imposition of a FIP in lieu of its SIP to curb regional haze.
—Sonal Patel, associate editor (@POWERmagazine, @sonalcpatel)