The Mammoth Geothermal Complex is located in the Eastern Sierra Nevada mountain range in California. It features three power plants that generate 29 MW, enough electricity for 22,000 homes. Ormat, the world leader in the geothermal market, owns the facility.
The first power plant, G1 (MP1), started operations in 1984 and G2 (MPII) and G-3 (PLES-1) came online in 1990. All the power plants use air-cooled binary technology. The G1 power plant was the first binary power plant in California and the world’s first air-cooled geothermal power plant to incorporate two closed-loop systems. In 2005, the wellfield was expanded into what is known as Basalt Canyon west of the power plants. Two production wells were drilled and connected to the existing power plants. Ormat repowered the G1 power plant in 2014 replacing 30-year old equipment with Ormat-manufactured OECs to improve its efficiency.