Mazama Energy raises $135 million for super-hot-rock geothermal

Geothermal startup Mazama Energy has raised $135 million in an oversubscribed Series B round, the company said. The funding will support horizontal wells in super-hot rock that Mazama says can generate up to 15 megawatts of electricity per well.

Mazama plans to begin generating electricity sometime next year. Its first site in Oregon is now estimated to be capable of producing 10 gigawatts, up from the 5 gigawatts investor Vinod Khosla cited last year.

The company has drilled past 10,000 feet in 15 days on its way to about 15,000 feet. At that depth, Mazama says it can access heat of 750°F (400°C). Under high pressure, the heat turns water into a “supercritical” fluid that can absorb more energy than ordinary steam. Mazama says each well could produce up to 10 times more power than traditional geothermal technology.

According to the University of Twente and the Clean Air Task Force, tapping 1% of the world’s super-hot rock could generate more than 63 terawatts of electricity. Mazama said work in Oregon remains in its early stages, but it has secured land for a second development. The company aims to complete its first site by 2030 and says it should generate 200 megawatts then. The round was led by Centaurus Capital and Doerr Capital, with participation from ConocoPhillips and Shell Ventures, while existing and new investors also joined.