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OCT 1 4 2008 *NORITHEERN BLIC AGENCY ENVIRONMENT HEALTH �� RNIA POWER AGENCY PERMIT/SERVICES 651 Commerce Drive Roseville, CA 95678 (9 16) 781-3636 www.ncpa.com October 10,2008 Adam Freedman U.S. Environment Protection Agency, Region IX 75 Hawthorne Street San Francisco, CA 94105 Subject: Permit Application for Class 1 Underground Injection Well Dear Mr. Freedman: Enclosed is the Northern California Power Agency (NCPA) Underground Injection Control Permit Application for the STIG-LEC facility. This permit application serves as the re-application for the existing steam injected gas turbine (STIG)-1 injection well. It also is the application for the Lodi Energy Center (LEC)-1 injection well to support the LEC. Construction of the LEC is planned to begin in first quarter 2010. In addition, a third injection well (LEC-2) is included in the application. It may be drilled in the future to serve as the backup well to both the existing STIG-1 well and the new LEC-1 well. The existing and proposed injection wells are defined as Class 1 wells under Title 40 Code of Federal Regulations (40 CFR)Subsection 144.5. Fluid injection at the STIG-LEC facility would be at a maximum rate of 425 gallons per minute (gpm). The existing STIG-1 well currently is permitted to inject up to 200 gpm,which is the same rate assumed in the re-application. The proposed injection rate of the LEC-1 well is 225 gpm. LEC-2, the proposed backup well,would not operate at a rate higher than 225 gpm and would serve as a backup well to either STIG-1 or LEC-1 at any given time, but would not back up both wells concurrently above a rate of 225 gpm.STIG-1 injects into the Domengine Formation at depths of between 4,234 and 4,507 feet,and the new wells would inject within the same zone. The composition of the STIG-1 injectate is expected to remain between 400 and 1,000 mg/L total dissolved solids (TDS),as it has since the well began routine operation in 2000, unless it is backing up the LEC-1 well. The composition of the LEC-1 injectate is modeled to be about 2,186 mg/L TDS. TDS values within the Domengine Formation are approximately 14,000 TDS. No underground sources of drinking water are expected to be affected by the proposed injection operations at the STIG-LEC facility. NCPA and its consultants, CH2M HILL and Worley-Parsons, look forward to working with the EPA in a manner that will result in a timely issuance of the permit. Our intention is to drill and test the LEC-1 in fourth quarter 2009, prior to initiating construction at the LEC.