Opinion of the Court
ternative is established as BACT unless the applicant demonstrates, and the permitting authority in its informed judgment agrees, that technical considerations, or energy, environmental, or economic impacts justify a conclusion that the most stringent technology is not 'achievable' in that case. If the most stringent technology is eliminated in this fashion, then the next most stringent alternative is considered, and so on." EPA, New Source Review Workshop Manual B.2 (Draft Oct. 1990) (hereinafter New Source Review Manual); App. 61-62.7
Applying top-down methodology, ADEC first homed in on SCR as BACT for MG-5, and the new generator, MG-17. "[W]ith an estimated reduction of 90%," ADEC stated, SCR "is the most stringent" technology. Id., at 79. Finding SCR "technically and economically feasible," id., at 65, ADEC characterized as "overstated" Cominco's cost estimate of $5,643 per ton of nitrogen oxide removed by SCR, id., at 113. Using Cominco's data, ADEC reached a cost estimate running between $1,586 and $2,279 per ton. Id., at 83. Costs in that range, ADEC observed, "are well within what ADEC and EPA conside[r] economically feasible." Id., at 84. Responding to Cominco's comments on the preliminary permit, engineering staff in ADEC's Air Permits Program pointed out that, according to information Cominco provided to ADEC, "SCR has been installed on similar diesel-fired engines throughout the world." Id., at 102.
Despite its staff's clear view "that SCR (the most effective individual technology) [was] technologically, environmentally, and economically feasible for the Red Dog power plant engines," id., at 103-104, ADEC endorsed the alternative prof-7 Nothing in the Act or its implementing regulations mandates top-down analysis. See 42 U. S. C. § 7479(3); 40 CFR § 52.21(j) (2002). EPA represents that permitting authorities "commonly" use top-down methodology. Brief for Respondents 3.Page: Index Previous 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Next
Last modified: October 4, 2007