Geothermal 1 is a regulated geothermal power plant located in Middletown, California, within the Western Electricity Coordinating Council (WECC) region. The facility operates with a capacity of 110 megawatts and is managed under the California Independent System Operator’s jurisdiction. The plant is primarily owned and operated by the Northern California Power Agency, which also serves as the holding company. In addition to the Northern California Power Agency, Silicon Valley Power is recognized as another owner of the facility.