Calistoga Geothermal Project - Unit 19

The Calistoga Geothermal Project (Unit 19) is in Lake County near the Sonoma/Lake County line, in the Geysers Known Geothermal Resource Area along the ridgeline of the Mayacamas Mountains with moderately steep terrain, approximately 15 miles west of the town of Cobb. Unit 19, originally known as Occidental (Oxy) Geothermal Power Plant No. 1 (Oxy #1) was certified by the California Energy Commission (CEC) in February 1982, and the plant began commercial operation in April 1984.

Unit 19 was designed to provide 80 megawatts of base-load electricity to northern California's power grid; however, due to reduced steam pressures, Unit 19 currently (as of January 2021) provides 69 MW of baseload power. Unit 19 major structures include the turbine building, cooling towers, hydrogen sulfide abatement, and the service building.

Between 1982 and 1999, OXY No. 1 underwent several ownership transfers and name changes within corporate entities, In November 1984, Occidental Geothermal, Inc. stock was purchased by Santa Fe International Corporation and the name was changed to Santa Fe Geothermal Plant No. 1. In April 1997, Santa Fe International Corporation sold Santa Fe Geothermal, Inc. to ESI Geothermal, Inc. (a division of Florida Power & Light (FPL) that was subsequently renamed FPL Energy). ESI renamed Santa Fe Geothermal, Inc. Silverado Geothermal Resources, Inc. (Silverado). Silverado immediately sold the power plant to Calistoga Geothermal Partners, LP.

In November 1999, the CEC granted a transfer in ownership of Unit 19 from Calistoga Geothermal Partners, LP to Geysers Power Company, LLC, both indirect wholly owned subsidiaries of Calpine Corporation. Calpine purchased 100 percent of the stock in Calistoga Geothermal Partners, LP and Silverado and renamed the facility Calistoga (Unit 19).