Best Available Retrofit Technology at the Cholla Power Plant

Cholla is one of the worst visibility-impairing coal plants in the nation, and the Conservation Organizations strongly support Arizona Public Service Company (APS) and PacifiCorp’s commitment to stop burning coal at Cholla. Unfortunately, compared to Cholla’s existing BART requirements, ADEQ’s proposal would result in greater air pollution and worse visibility impairment at Arizona’s national parks and wilderness areas for nearly two decades after the BART compliance deadline. The proposal thus weakens Cholla’s existing BART determination in violation of the Clean Air Act’s anti-backsliding provision. Fortunately, ADEQ’s analysis shows it would be cost effective to install updated pollution controls that would substantially reduce Cholla Unit 3 and 4’s pollution before they stop burning coal in 2025. At a minimum, Selective Non-Catalytic Reduction (SNCR) controls should be BART. Moreover, a proper analysis shows that highly-effective Selective Catalytic Reduction (SCR) controls are the “best available” controls and should be BART. Accordingly, in order to ensure the BART “reassessment” complies with the Act, ADEQ should revise its BART determination and require Units 3 and 4 to install these updated, cost-effective pollution controls by the BART compliance deadline.