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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 66 (1982)

Issue: 11. (November)

First Page: 2489

Last Page: 2499

Title: Developments in Geothermal Resources in 1981

Author(s): Jim Combs (2), C. W. Berge (3), John W. Lund (4), David N. Anderson (5)


Several significant developments in the geothermal industry may change the course of geothermal development. The U. S. Department of Energy budget for fiscal year 1981-82 was reduced drastically. Natomas Co. acquired Magma Power Co., thereby changing participants in the development of The Geysers and providing acknowledgment by financial institutions of the value of geothermal reserves. California Energy Co., Inc., with its dry steam discovery well, established commercial production at the Coso Hot Springs KGRA in late 1981. There was dramatic acceleration in releasing federal lands for geothermal leasing. Finally, Occidental Geothermal, Inc., announced that it will build and operate an 80 MWe power plant near Anderson Springs, California, selling the electricity to Pacif c Gas and Electric Co. under the Public Utilities Regulatory Act (PURPA).

Drilling of geothermal exploration and development wells showed a slight increase over 1980. In 1981, 99 wells accounted for 674,781 ft of hole. A total of 203,673 ft of hole was cut during the drilling of 37 geothermal exploratory wells. California again had the largest number of wildcats at 16, followed by Nevada with 10. Eight successful wildcats accounted for 34,862 ft of hole, with an average total depth of 4,358 ft. These include wells capable of producing dry and wet steam, as well as ones intended for direct-use applications. The wildcat success rate was 21.62%, down from the 1980 success rate of 47.37%. Of the 62 geothermal development wells in 1981, representing 471,108 ft of hole, 56 were considered capable of production. The development success rate of 90.32% is slightly b low the 1980 success rate of 94.83%. Also, there has been a significant increase in average depth, from 5,997 ft in 1980 to 7,901 ft in 1981. This seems to indicate that operators are having to drill deeper in their efforts to extend productive limits of proven geothermal reservoirs.

Although there have been no new geothermal electrical power plants brought on-line in The Geysers during 1981, construction continued on 6 plants, with a combined capacity of 537 MWe, scheduled to become operational during 1982 through 1984. A strong trend is emerging in the area of power generation from geothermal resources: the development of small power plants (i.e., those of 1.5 to 20 MWe capacity). Two small facilities, 1 of 3 MWe at the Puna District in Hawaii and 1 of 1.6 MWe at the Roosevelt Hot Springs KGRA in Utah, became operational in 1981. This movement toward smaller, semiportable, less expensive power plants is healthy, and is indicative of the desire of utilities and geothermal operators to solve their mutual problems. With the approval for 2 new electrical transmissio lines, a major impediment to the eventual development of geothermal resources in The Geysers and the Imperial Valley has been removed. The construction of district heating projects highlights direct-use applications of geothermal energy in 1981.

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