Nevada-based Ormat paid US energy producer Constellation $72.5m for its share in the partnership.
This gives it sole ownership of land, three geothermal power plants with a capacity of 29MW, associated equipment, and rights to more than 40 square kilometres of land at the complex, located in east-central California within Yosemite National Park.
Ormat chief executive Dita Bronicki says: “As the sole owner of the complex, we plan to move quickly to expand the facility with a goal to double generation capacity.
"Mammoth