Mazama Energy raises $135M for super-hot-rock geothermal
Original: Khosla-backed Mazama Energy just raised $135M to drill deeper into super-hot-rock geothermal
Why This Matters
Super-hot geothermal is emerging as a serious baseload alternative to natural gas for AI data center power demand.
Geothermal startup Mazama Energy closed an oversubscribed $135M Series B on September 17, 2026. Led by Centaurus Capital and Doerr Capital, with ConocoPhillips and Shell Ventures among new backers, the funds will develop horizontal wells in super-hot rock targeting 15 MW per well and 200 MW total by 2030.
Mazama Energy, incubated at Khosla Ventures, has raised $135 million in a Series B to push enhanced geothermal technology deeper than anyone has drilled commercially. The round was oversubscribed and led by Centaurus Capital and Doerr Capital, with ConocoPhillips, Shell Ventures, SiteGround Capital, H. Barton Asset Management, and the Jeffrey and Marieke Rothschild Foundation joining existing backers Khosla Ventures and Gates Frontier.
The company's approach targets super-hot rock at roughly 15,000 feet — a depth it has reached in 15 days of drilling. At those depths, temperatures hit 750°F (400°C), turning water into a supercritical fluid that absorbs far more energy than conventional steam. Mazama says each well can generate up to 15 MW, roughly ten times more than traditional geothermal wells.
The flagship Oregon site, previously estimated by investor Vinod Khosla to hold 5 GW of potential, has now been revised upward to 10 GW. Mazama plans to begin generating electricity in 2027 and expects the Oregon site to reach 200 MW by 2030. A second site has already been secured. According to research from the University of Twente and the Clean Air Task Force, tapping just 1% of the world's super-hot rock could yield over 63 terawatts of electricity globally.