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SECTION 6.0:ALTERNATIVES <br /> the boiler. This is an outdated technology that is able to achieve thermal efficiencies up to <br /> approximately 36 percent when utilizing natural gas,although efficiencies are somewhat <br /> higher when utilizing oil or coal. Because of this low efficiency and large space requirement, <br /> the conventional boiler and steam turbine technology was eliminated from consideration. <br /> 6.6.1.2 Conventional Simple-Cycle Combustion Turbine <br /> Conventional aero-derivative turbine-generator units are able to achieve thermal efficiencies <br /> up to approximately 38 percent. A simple-cycle combustion turbine has a quick startup <br /> capability and lower capital cost than that of a combined-cycle,and is very appropriate for <br /> peaking applications. Because of its relatively low efficiency,conventional simple-cycle <br /> technology tends to emit more air pollutants per kilowatt-hour. Because of this relatively <br /> low efficiency, the conventional simple-cycle combustion turbine technology was eliminated <br /> from consideration. <br /> 6.6.1.3 Kalina Combined-Cycle <br /> This technology is similar to the conventional combined-cycle, except a mixture of ammonia <br /> and water is used in place of pure water in the steam cycle. The Kalina cycle could <br /> potentially increase combined-cycle thermal efficiencies by several percentage points. This <br /> technology is still in the development phase and has not been commercially demonstrated; <br /> therefore,it was eliminated from consideration. <br /> 6.6.1.4 Internal Combustion Engines <br /> Internal combustion engine designs are also available for small peaking power plant <br /> configurations. These are based on the design for large marine diesel engines,fitted to burn <br /> natural gas. Advantages of internal combustion engines are as that they: (1) use very little <br /> water for cooling,because they use a closed-loop coolant system with radiators and fans; <br /> (2) provide quick-start capability (on-line at full power in 10 minutes) and (3) are responsive to <br /> load-following needs because they are deployed in small units (for example, 10 to 14 engines <br /> in one power plant),that can be started up and shut down at will. Disadvantages of this design <br /> include somewhat higher emissions than comparable combustion turbine technology. In <br /> addition,internal combustion engine installations are generally deployed at less than 150 MW, <br /> and so would not meet one of the project objectives,which is for 255 MW of peaking power. <br /> 6.6.2 Fuel Technology Alternatives <br /> Technologies based on fuels other than natural gas were eliminated from consideration <br /> because they do not meet the project objective of utilizing natural gas available from the <br /> existing transmission system. Additional factors rendering alternative fuel technologies <br /> unsuitable for the proposed project are as follows: <br /> • No geothermal or hydroelectric resources exist in San Joaquin County. <br /> • Biomass fuels such as wood waste are not locally available in sufficient quantities to <br /> make them a practical alternative fuel and LEC site space is limited. <br /> • Solar and wind technologies are generally not dispatchable and are,therefore,not capable <br /> of producing ancillary services other than reactive power, and LEC site space is limited. <br /> • Coal and oil technologies emit more air pollutants than technologies utilizing natural gas. <br /> SAC/371322/082330003(LEC_6.0_ALTERNATIVES.DOC) 6-15 <br />