ARCHIVED REPORTS LEC APPLICATION FOR CERTIFICATION

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SECTION 2.0:PROJECT DESCRIPTION sparging steam), and heating the gas turbine fuel gas. The auxiliary boiler is designed to control delivery pressure and steam quality over a broad range of steam demands. The minimum steam demand normally occurs during pre-start activities when supplying seal steam only to the steam turbine glands before condenser vacuum is established (approximately 20,000 lb/hr). Maximum demand occurs when supplying maximum steam turbine sealing steam,maximum condenser sparge steam,maximum feedwater heating steam,and gas turbine inlet air heating(approximately 45,000 lb/hr). Therefore,the auxiliary boiler steam supply system includes a pressure control system that vents to the atmosphere to limit auxiliary boiler operating pressures during periods of low steam demands and/or rapid reductions in steam consumption during transients. The auxiliary boiler is designed to achieve a turndown ratio of 4:1. The auxiliary boiler will be equipped with ultra-low NOX burners to reduce NOX emissions and will be fueled with natural gas exclusively to minimize emissions of other criteria and non-criteria pollutants. 2.1.7 Major Electrical Equipment and Systems The bulk of the electric power produced by the facility will be transmitted to the electrical grid through the existing 230-kV, double-circuit line adjacent to NCPA's existing 49-MW STIG plant. A small amount of electric power will be used on site to power auxiliaries such as pumps and fans,control systems, and general facility loads including lighting,heating, and air conditioning. A station battery system will also be used to provide direct current (DC) voltage to be used as backup power for control systems and other uses. Transmission and auxiliary uses are discussed in the following subsections. 2.1.7.1 AC Power—Transmission Power will be generated by the CTG and the STG at 18 kV and then stepped up by a single, fan-cooled,three-winding, generator step-up (GSU) transformer to 230 kV for connection to the grid. Auxiliary power will be back-fed through the step-up transformer. Once the unit is running,it will supply its own auxiliary power. Surge arresters will be provided at the transformer high-voltage bushings to protect the transformer from surges on the 230-kV system caused by lightning strikes or other system disturbances. The transformer will be set on a concrete pad within a berm designed to contain the non-PCB transformer oil in the event of a leak or spill. The high-voltage side of the step-up transformer will be connected to a new gas insulated (SF6) circuit breaker to be installed in the existing substation and connected via an overhead transmission line.From the substation,power will be transmitted to the grid via transmission lines owned by Pacific Gas and Electric Company (PG&E). Section 3.0,Electrical Transmission,contains additional information regarding the electrical transmission system as well as a summary of the System Impact Study. 2.1.7.2 AC Power—Distribution to Auxiliaries Auxiliary power to the combustion turbine will be supplied at 4,160 volts and 480-volt alternating current(AC) by 4,160-volt switchgear lineups and 480-volt switchgear lineups. Two oil-filled using less flammable oil,18-to 4.16-kV unit auxiliary stepdown transformers will supply primary power to the switchgear and then subsequently to large motor loads including the fuel gas compressors and to the 4.16 kV side of the 4.16-kV/480-volt, oil-filled SACI371322I082340003(LEC_2.0_PROJECT_DESC.DOC) 2-17