Appeals court sides with EPA in fight over NOX control for Coronado coal plant

A three-judge panel at the U.S. Ninth Circuit Court of Appeals on Feb. 24 rejected a bid by the state of Arizona and the Salt River Project to overturn a U.S. Environmental Protection Agency decision mandating new NOx controls for the coal-fired Coronado power plant under EPA’s regional haze program.

The panel held that the EPA in 2012 did not act arbitrarily and capriciously when it disapproved in part the Arizona State Implementation Plan’s (SIP) “best available retrofit technology” for the Coronado Generating Station, and when it issued a replacement Federal Implementation Plan (FIP) in place of the disapproved portions. The panel also held that the EPA did not err procedurally in promulgating the FIP in the same rule as its partial disapproval of the SIP. The panel held that its ultimate review of the EPA’s FIP must await the EPA’s final action on its proposal to revise the FIP in specific respects. Accordingly, the panel on Feb. 24 stayed the proceedings as to evaluation of the FIP’s technical feasibility until the administrative process was complete.

Coronado Generating Station is a two-unit, 733-MW coal plant located in Eastern Arizona.

Arizona had determined that the proper control technology was low-NOX burners with overfire air. Its proposed SIP established enforceable NOX emissions limits of 0.32 lb/mmBtu for both units of the Coronado facility.

EPA, however, concluded that selective catalytic reduction (SCR) with low-NOX burners and overfire air — the most stringent available retrofit control option — was the proper BART control for Coronado. EPA proposed NOX emission limits much lower than those contained in Arizona’s SIP: 0.050 lb/mmBtu (calculated on a rolling 30-boiler-operating-day average) for Coronado Unit 1, and 0.080 lb/mmBtu for Coronado Unit 2. In the Final Rule, EPA revised certain elements of the proposed FIP in response to public comments and additional information. Notably, EPA weakened the final NOX emissions limits to “provide an extra margin of compliance” and changed its methodology to require plant-wide averaging. EPA changed its proposed NOX emission limits from 0.050 lb/mmBtu for Coronado Unit 1 and 0.080 lb/mmBtu for Coronado Unit 2 to an averaged limit of 0.065 lb/mmBtu across both units of the Coronado facility. The Final Rule also extended the compliance deadlines for installation and operation of the controls at the facilities.

Looking at some conclusions in the Feb. 24 decision:

  • Arizona maintained that, in acting only on the BART determinations when it promulgated the Final Rule, deferring action on the rest of the SIP, EPA “misconstrued its statutory authority and acted in an arbitrary fashion.” Said the court decision: “That is not so. There is no requirement that EPA approve or disapprove a SIP submittal in a single action.”
  • Arizona and SRP contended that each of EPA’s conclusions is legally flawed and unsupported by the record, making the partial disapproval of the SIP arbitrary and capricious. “We disagree,” said the court. “EPA’s conclusions concerning the State’s BART analysis and determinations were well explicated, carefully grounded in the administrative record, and analytically reasonable, and so properly support its disapproval of Arizona’s NOX BART determinations for Coronado.”
  • There was a dispute over Arizona’s cost analysis for the various NOX controls possible for Coronado. The court noted: “Arizona simply relied on the cost data provided by SRP, despite the fact that the data failed to include sufficient detail for the State meaningfully to analyze the reasonableness of the costs of various control alternatives. States are required by statute to consider ‘costs of compliance’ in making BART determinations. When they are not presented with enough data to do so, EPA may reasonably conclude that their analysis is inadequate. EPA’s decision to do so was not arbitrary or capricious.”
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.