Promulgation of Air Quality Implementation Plans; Arizona; Regional Haze Federal Implementation Plan; Reconsideration

The Environmental Protection Agency (EPA) is proposing to revise part of the Arizona Regional Haze (RH) Federal Implementation Plan (FIP) applicable to the Coronado Generating Station (Coronado). In response to a petition for reconsideration from the Salt River Project Agricultural Improvement and Power District (SRP), the owner/operator of Coronado, we are proposing to replace a plant-wide compliance method with a unit-specific compliance method for determining compliance with the best available retrofit technology (BART) emission limits for nitrogen oxides (NOX) from Units 1 and 2 at Coronado. While the plant-wide limit for the NOX emissions from Units 1 and 2 were established as 0.065 lb/MMBtu, we are proposing a unit-specific limit of 0.065 lb/MMBtu for Unit 1 and 0.080 lb/MMBtu for Unit 2. In addition, we are proposing to revise the work practice standard in the FIP for Coronado. Finally, we are proposing to remove the affirmative defense for malfunctions from the Arizona RH FIP, which applies to both Coronado and the Cholla Power Plant (Cholla).