ARCHIVED REPORTS LEC APPLICATION FOR CERTIFICATION

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5.1C:EVALUATION OF BEST AVAILABLE CONTROL TECHNOLOGY 5.1C.1.1.1.3 Conclusion Because both SCR and EMx are expected to achieve the proposed BACT NOx emission limit of 2.0 ppmvd @ 15% 02 averaged over one hour and neither will cause significant energy, economic, or environmental impacts,neither can be eliminated as viable control alternatives.The concern remains regarding the long-term effectiveness of EMx as a control technology as the technology has not been demonstrated on the turbine used in this project. In addition,LEC is utilizing the new Rapid Response startup process for this turbine (discussed in more detail below) so will already be challenged with integrating a new technology,with the potential for much larger emissions reductions. For these reasons,and because SCR is already in use at the facility,SCR has been selected as the NOx control technology to be used for the LEC. 5.1C.1.1.1.4 Conclusions BACT must be at least as stringent as the most stringent level achieved in practice,federal NSPS, or district prohibitory rule. Based upon the results of this analysis,the NOx BACT determination of 2.0 ppm @ 15% 02 on a 1-hour average basis made for recently permitted combined cycle turbine projects in SJVAPCD and elsewhere reflects the most stringent achievable NOx emission limit. The LEC facility will be designed to meet a NOx level of 2.0 ppmv @ 15% 02 on a 1-hour average basis using SCR. 5.1C.1.2 CO Emissions 5.1C.1.2.1 Achievable Controlled Levels and Available Control Options Oxidation catalyst technology is commonly used to control CO emissions. The CARB's BACT guidance document for electric generating units rated at greater than 50 MW4 indicates that BACT for the control of CO emissions from stationary gas turbines used for combined-cycle and cogeneration power plants is 6 ppmvd @ 15% 02. The BAAQMD's BACT guidelines specify that,for natural gas-fired combined-cycle gas turbines larger than 40 MW,a CO limit of 4 ppmv @ 15% 02 has been"achieved in practice." The SJVAPCD's BACT guidelines contained determinations for gas turbines larger than 50 MW with uniform load and with heat recovery. The SJVAPCD concluded that a CO exhaust concentration of 6 ppmv @ 15% 02 constituted BACT that had been achieved in practice, while 4.0 ppmv @ 15% 02 is considered technologically feasible. A summary of recent CO BACT determinations for large,combined-cycle gas turbines is shown in Table 5.1C-2. Similar facilities using oxidation catalysts have been permitted at between 2.0 and 4.0 ppm CO. CO emission limits for projects in the SCAQMD may be considered to go beyond BACT because (1) the District is a nonattainment area for CO,so more stringent control requirements apply;and (2) applicants in the SCAQMD are required to provide offsets for CO, so there is additional incentive to reduce CO emission levels beyond BACT to minimize offset requirements. We are not aware of any available in-use data that shows whether compliance with the 2.0 ppm limits has been demonstrated in practice. 4 CARB, "Guidance for Power Plant Siting and Best Available Control Technology,"July 1999. SAC/371322/082330016(LEC_5.1 C_APPENDIX.DOC) 5.1C7