SOLAR THERMAL ELECTRIC CONVERSION BASIC AND TUTORIALS

HOW TO TURN SOLAR HEAT INTO ELECTRICITY?


Southern California Edison’s grid with an overall system efficiency in the range of 7 to 8%. With improvements in heliostat and receiver technologies, annual system efficiencies of 14 to 15% and generation cost of 8 to 12¢/kWh have been projected.

Parabolic-dish electric-transport technology for DG was under active development at the Jet Propulsion Laboratory (JPL) in Pasadena, California, in the late ’70s and early ’80s. Prototype modules with Stirling engines reached a record 29% overall efficiency of conversion from insolation to electrical output.

Earlier parabolic dish designs collected and transported thermal energy to a central location for conversion to electricity. Advanced designs such as the one developed at JPL employed engine driven generators at the\ focal points of the dishes, and energy was collected and transported in electrical form.

By far the largest installed capacity (nearly 400 MW) of solar-thermal-electric DG employs parabolic-trough collectors and oil to transport the thermal energy to a central location for conversion to electricity via a steam-Rankine cycle.

With the addition of a natural gas burner for hybrid operation, this technology, developed by LUZ under the code name SEGS (solar electric generating system), accounts for more than 90% of the world’s solar electric capacity, all located in Daggett, Kramer Junction, and Harper Lake in California.

Generation costs of around 8 to 9¢/kWh have been realized with SEGS. This technology uses natural gas to compensate for the temporal variations of insolation and firms up the power delivered by the system. This compensation may come during 7 to 11 P.M. in summer and during 8 A.M. to 5 P.M. in winter.

SEGS will require about 5 acres/MW or can deliver 130 MW/mi2 of land area.

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