Pacific Gas and Electric Co.
Geysers Road near Healdsburg
Sonoma Cty, Geysersville, CA

Image: Credit: Pacific Gas & Electric Company Copyright authorization is limited to the promotion of the ASME landmarks program, in most cases, and therefore permission to use this image is restricted.  

Notable for: first commercial geothermal electricity-generating station in North America

More about . . .
Geysers Unit 1, the first commercial geothermal electric generating station in North America, was a rebuilt kilowatt-size General Electric generator installed by the Pacific Gas and Electric Company engineers. From this initial turbogenerator grew the largest geothermal development in the world, pioneering the design of systems to provide corrosion-resistant cooling, remove noncondensible gas, and provide environmental controls.

The field was first discovered in 1847 and minor attempts to develop it were made in 1922, but the steam that billowed from fumaroles was too corrosive for the piping and materials technology of the day. Though the Larderello, Italy, geothermal fields are the world's first geothermal power-generation development, the Geysers is the largest vapor-dominated geothermal system, ideal for electricity generation in that steam rises by natural means and can be applied directly to the turbine. It provides a fairly clean, slightly super-heated dry steam. Today more than two hundred wells and thirteen generators produce 665,000 net cumulative kilowatts.

Ceremony Notes: October 1985