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50 Years of Development at The Geysers
The Second Decade - 1970s

Map of the Geysers Geothermal Field © Geysers Geothermal Assn. 2010

Commercial Development at The Geysers from 1970-1979

1970 PG&E agreed to construction of up to 6 additional generation units (5,6,7,8,9,&10), each with 55MW capacity.The Geysers was on its way to becoming one of the major geothermal fields of the world. Units 5 and 6 are shown in photo below.

(Photo courtesy Ted Wilmsen)

1974 PG&E entered into steam purchase agreements with GRI and Signal Oil. Sun Oil, Geothermal Kinetics and McCullough Oil Company all acquired diverse lease positions and prepared to drill.

1974 PG%E Unit 11 goes online

         Burmah Oil Company acquired Signal's holdings.

         Drilling depth now routinely reached 7000 or 8000 ft.

B.C. McCabe in 1974 (Photo courtesy Ted Wilmsen)

1978 - 1979 Northern California Power Agency contracted to buy steam
        from Shell Oil.

        Sacramento Municipal Utility District entered into a steam purchase 
        agreement with Aminoil USA (successor-in-interest to Burmah)

        Burmah Oil Company acquired Signal's holdings.        

        California Dept of Water Resources contracted with MCR Geothermal Corp.
        for steam from its Bottle Rock leasehold.

1979 PG&E Units 12 and 15 go online.

        Occidental Geothermal began drilling on its leasehold acquired in the 1979
        federal lease sale.

Technical Advances and Legislation at The Geysers 1970 - 1979

1970 The Geothermal Resources Council is formed to encourage the development of geothermal resources worldwide. The Federal Geothermal Steam Act of 1970 (Public Law 91-581) further defined geothermal resources.

1973 -1974 Oil price shocks provided both a justifcation and a stimulus for geothermal development. First Federal lease sale.

1974 With the passage of the Safe Drinking Water Act (SDWA), the subsurface injection of injected waste water came under federal regulation.

1975 President Gerald Ford flew by helicopter from Hamilton AFB to "The Geysers" geothermal power field.

late1970s The USGS seismic array was established. Tracer testing was begun to better understand steam/water movement throughout the reservoir.

1978 -1979 Average conversion rates in new power plants decreased from 18 to 20 pounds of steam per kWh to 14 or 15 pounds.  Purchase terms in newer contracts were based on energy delivered rather than power generated, and pricing reflected open market price for fuel. Terms also encouraged greater efficiency in use of supplied steam.

1978 The Public Utility Regulatory Policy Act (PURPA) required electric utilities to purchase electricity from specially qualified independent producers at the utilities' avoided cost of new generation. PURPA was passed in 1978, and became effective in 1982. It was intended to encourage the entrance of small power generators into the market. Bear Canyon, West Ford Flat, Aidlin, and Santa Fe were PURPA projects.

To view the period of Commercial Development of The Geysers in the 1980s, click here

Map of the Current Geysers Geothermal Field

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Geysers Geothermal Association Website (Updated April 20, 2011)
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