The Telephone Flat Geothermal Field has a possible potential of over 100 Megawatts of electrical potential. The site consists of over 5,000 acres of leased BLM land located at an elevation of about 6,800 feet within the broad volcanic highland known as Medicine Lake Volcano. This area is known for several spectacular about 1,000 year old volcanic flows, the largest being Glass Mountain, and a recreation area associated with Medicine Lake. The geothermal reservoir is over 480ºF and is associated with deep water circulation around a cooling magma body.
In 2006 and 2007, Earth Systems assisted the Calpine Corporation, the lease holder and operator of the project, in preparing and getting acceptance of a groundwater monitoring plan through the Central Valley Regional Water Quality Control Board. With planned depths of up to 400 feet, the groundwater monitoring wells present unique challenges in that they will be drilled through solid volcanic rock, at formation temperature up to 100ºF, in an area that gets over 10 feet of snow each winter, and with an attention to materials of completion to allow for detection of water contaminates in the parts per billion range.
Earth Systems’ key geothermal expert has been associated with the project since 1982. He helped direct the exploration program for the area; the work culminated in the successful drilling of the deep discovery well, GMF-68-8.