“The Geysers is the world’s largest geothermal field, containing a complex of 22 geothermal power plants, drawing steam from more than 350 wells, located in the Mayacamas Mountains approximately 72 miles (116 km) north of San Francisco, California.”
https://en.wikipedia.org/wiki/The_Geysers
Thank you everyone who responded to me. I didn’t know this. Now I am well informed because of fellow Freepers!