Mazama Energy Raises $135M to Advance Super-Hot Geothermal Power
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Mazama Energy, a geothermal startup backed by Khosla Ventures, has raised $135 million to advance its efforts to generate electricity from some of the hottest rocks deep beneath the Earth’s surface.
The company announced the funding on Thursday, calling it an oversubscribed Series B round. The capital will support the development of horizontal wells drilled into super-hot rock, with each well designed to generate as much as 15 megawatts of electricity.
Mazama expects to begin generating power sometime next year. Its first project, located in Oregon, is now estimated to have the potential to produce 10 gigawatts of electricity. That figure is double the 5-gigawatt estimate shared last year by investor Vinod Khosla.
Going Deeper for More Power
Mazama’s approach focuses on geothermal resources found much deeper underground than those used by traditional geothermal projects. The company has drilled beyond 10,000 feet in just 15 days as part of its progress toward a target depth of approximately 15,000 feet.
At those depths, temperatures can reach around 750°F (400°C). Under high pressure, water can become a “supercritical” fluid—a state that is neither fully liquid nor fully gas. This fluid can absorb substantially more energy than ordinary steam, potentially allowing Mazama’s wells to produce up to 10 times more power than conventional geothermal technologies, according to the company.
The opportunity is drawing increasing attention as energy demand rises, particularly from artificial intelligence data centers and other large electricity consumers. Enhanced geothermal startups are emerging as an alternative in a market where technology companies and data center developers have also been investing heavily in natural gas.
The potential resource is enormous. Research from the University of Twente and the Clean Air Task Force estimates that tapping just 1% of the world’s super-hot rock could generate more than 63 terawatts of electricity.
Oregon Project Targets 2030 Completion
Mazama’s Oregon development remains in its early stages, but the company has already secured land for a second project. It aims to complete development of its first site by 2030, with a projected generation capacity of 200 megawatts at that point.
The latest funding round was led by Centaurus Capital and Doerr Capital. ConocoPhillips and Shell Ventures also participated, while existing backers Khosla Ventures and Gates Frontier returned for the round.
New investors included SiteGround Capital, H. Barton Asset Management, and the Jeffrey and Marieke Rothschild Foundation.
Mazama Energy was incubated at Khosla Ventures, which has continued to support the startup as it develops its super-hot-rock geothermal technology.
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