ARCHIVED REPORTS LEC APPLICATION FOR CERTIFICATION

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5.1 AIR QUALITY TABLE 5.1-25 BACT Determinations for LEC Pollutant Gas Turbine/HRSG Auxiliary Boiler NO. Dry low-NO,,combustor and selective catalytic Ultra-low NO,,burner: 7 ppmcb reduction: 2.0 ppmC,a 1-hour average CO Oxidation catalyst: Good combustion practices 3.0 ppmc, 3-hour average VOC 1.4 ppmc, no duct firing Good combustion practices 2.0 ppm,with duct firing 3-hour average SO2 and PM,o Natural gas fuel and good combustion Natural gas fuel and good combustion practices; inlet air filter; lube oil vent coalescer practices appmc: parts per million by volume, dry. Gas Turbine/HRSG concentrations are corrected to 15%02. bBoiler concentrations are corrected to 3%02. 5.1.5 Air Quality Impact Analysis SJVAPCD Rule 2201 requires the Applicant to provide ambient air quality modeling analyses and other impact assessments. An ambient air quality impact assessment is also required by EPA for PSD review and by the CEC for CEQA review. These analyses are presented in this section. The air quality impact analyses have been prepared in accordance with modeling protocols submitted to and reviewed by the SJVAPCD and CEC staffs.The protocols and the comments provided are included in Appendix 5.113. 5.1.5.1 Dispersion Modeling An assessment of impacts from the LEC on ambient air quality has been conducted using EPA-approved air quality dispersion models. These models are based on various mathematical descriptions of atmospheric diffusion and dispersion processes in which a pollutant source impact can be calculated over a given area. Figure 5.113-1 in Appendix 5.113 shows the building layout used in the modeling analysis. Since the new equipment will operate alongside the existing plant,the modeling analysis included the existing STIG plant structures to account for any potential influences from those structures. The impact analysis was used to determine the worst-case ground-level impacts of the new equipment. The results were compared with established state and federal ambient air quality standards and PSD significance levels. If the standards are not exceeded then it is assumed that,in the operation of the facility,no exceedances are expected under any conditions. In accordance with the air quality impact analysis guidelines developed by EPA (40 CFR Part 51,Appendix W: Guideline on Air Quality Models) and CARB (Reference Document for California Statewide Modeling Guideline,April 1989),the ground-level impact analysis includes the following assessments: • Impacts in simple,intermediate,and complex terrain; • Aerodynamic effects (downwash) due to nearby building(s) and structures; and • Impacts from inversion breakup (fumigation). Simple,intermediate, and complex terrain impacts were assessed for all meteorological conditions that would limit the amount of final plume rise. Plume impaction on elevated 5.1-32 SAC/371322/082410013(LEC_5.1_AIR_QUALITY.DOC)