| Abstract |
The Heber Geothermal Resource, in California was developed in the early 1980s by Chevron Geothermal Company to support of 500 MW of electrical power generation from 360oF geothermal fluids. By 1985 two power plants were sharing the resource: (a) the 47 MW (net) double flash HGC Plant owned by the Heber Geothermal Company and (b) the 45 MW (net) Heber Binary Power Plant owned by the San Diego Gas & Electric Company. The Heber Binary Plant was designed with a supercritical binary cycle and a single turbine-generator, rated for 70MW capacity with 23.5MW in parasitic power usage. The geothermal fluid for full output was to be 3,750,000 lbs/hr at 360oF. The plant went on line in 1985, with lower fluid temperature and a flow rate never more than 2, 700,000 lbs/hr. As a result the plant generated only 16.5 MW gross and 5MW net. With this low output, operation was discontinued and the plant was decommissioned by the owners. In 1992 the Second Imperial Geothermal Company contracted for the development of a modular binary power with 33MW net output from 330oF geothermal fluid. A sub critical cycle binary power plant incorporating 6 modules designed to generate 40 MW gross power, from 6,000,000 lbs/hr of 330oF fluid, was installed. The well field was developed so that there was no interference between the double flash plant and the modular binary plant. Construction was begun on the Second Imperial Geothermal (SIGC) Power Plant in December of 1992. The SIGC plant went into Commercial operation on July 2, 1993, producing 113% of its rated net output. Both plants at Heber are operated by Ogden Geothermal and are producing at design levels. |