Mazama Energy has collected $135 million in an oversubscribed Series B, giving the Oregon geothermal developer room to chase heat that conventional drilling cannot reach.
Centaurus Capital and Doerr Capital led the round. ConocoPhillips and Shell Ventures joined, alongside returning backers Khosla Ventures and Gates Frontier. SiteGround Capital, H. Barton Asset Management and the Jeffrey and Marieke Rothschild Foundation also took part.
The pitch rests on depth. Mazama has drilled beyond 10,000 feet in 15 days on its way toward roughly 15,000 feet, where rock reaches 400C. At those temperatures and pressures water becomes a supercritical fluid that carries far more energy than ordinary steam, which the company says lets a single well produce up to 10 times the power of a standard geothermal plant.
Each well is designed to deliver as much as 15 megawatts. Mazama expects to start generating electricity next year, and puts the long-run potential of its first Oregon site at 10 gigawatts, a big upgrade on the 5 gigawatts investor Vinod Khosla floated last year. Full development of that site is targeted for 2030, when it should supply 200 megawatts.
Enhanced geothermal has become a dark horse in the scramble to power AI data centers. Hyperscalers and developers have leaned heavily on natural gas, but drilling startups keep pushing costs and timelines down. Researchers estimate that tapping just 1% of the world’s superhot rock could yield more than 63 terawatts.
Mazama has already secured land for a second site. Whether supercritical wells scale on schedule is now the question investors are paying to answer.
