Mazama Energy Raises $135M to Tap Super-Hot Rock Geothermal

Mazama Energy has raised $135 million in an oversubscribed Series B round to advance its super-hot-rock geothermal technology and develop horizontal wells capable of generating up to 15 megawatts of electricity per well.

The geothermal startup plans to use the fresh capital to develop its wells in extremely hot rock formations deep underground, targeting temperatures of around 750°F (400°C). The company expects to begin generating electricity from its first Oregon site sometime in 2027.

Targeting super-hot geothermal energy

Unlike conventional geothermal projects, Mazama Energy is drilling deeper into hotter rock. The company has already drilled beyond 10,000 feet in 15 days and is targeting a depth of approximately 15,000 feet.

At those depths, Mazama expects to access temperatures of around 750°F. Under high pressure, water can become a supercritical fluid, a state between liquid and gas that can absorb substantially more energy than conventional steam.

Mazama says this approach could allow each well to generate up to 10 times more power than traditional geothermal technologies.

Oregon site could support large-scale generation

Mazama's first development site in Oregon is estimated by the company to have potential for up to 10 gigawatts of electricity generation, doubling its previously cited estimate of 5 gigawatts.

The company has also secured land for a second development site. Mazama aims to complete development of its first site by 2030, with a target of generating 200 megawatts of electricity.

The startup says a single well using its technology could generate up to 15 megawatts of electricity around the clock, potentially providing a continuous power source for large electricity consumers such as data centers.

Funding and investors

The $135 million Series B was led by Centaurus Capital and Doerr Capital, with participation from ConocoPhillips and Shell Ventures.

Existing investors including Khosla Ventures and Gates Frontier also participated. New investors in the round include SiteGround Capital, H. Barton Asset Management, and the Jeffrey and Marieke Rothschild Foundation.

Mazama Energy was incubated at Khosla Ventures.

The funding comes as enhanced geothermal companies advance technologies designed to access deeper and hotter underground resources, with the sector increasingly being considered for reliable electricity generation alongside other energy sources.