Geothermal energy startup Mazama Energy announced on Thursday that it has closed a $135 million Series B financing round, which was oversubscribed. The company stated that the capital will be used to advance the development of horizontal wells designed to extract energy from super-hot rock formations, with each well projected to generate up to 15 megawatts of electricity.
Mazama aims to begin generating power at its inaugural site in Oregon sometime next year. The company recently revised its capacity estimates for this location upward significantly, now claiming the site can produce 10 gigawatts of electricity. This marks a sharp increase from figures provided last year, when investor Vinod Khosla estimated the site’s potential at 5 gigawatts.
Enhanced geothermal systems are emerging as a competitive option for powering AI data centers and other high-demand grid loads. While many technology firms and data center developers have historically leaned toward natural gas, geothermal startups are rapidly advancing their capabilities. Unlike conventional geothermal projects, these newer initiatives target much deeper and hotter rock formations.
Mazama has demonstrated significant drilling speed, penetrating past 10,000 feet in just 15 days as it pushes toward a target depth of approximately 15,000 feet. At these depths, the company accesses temperatures of 750°F (400°C). Under extreme pressure, this heat converts water into a supercritical fluid—a state that is neither fully liquid nor gas—which allows the medium to absorb substantially more energy than traditional steam. Consequently, Mazama estimates that each well can produce up to ten times more power than standard geothermal technologies.
The scale of the opportunity is substantial. According to research from the University of Twente and the Clean Air Task Force, harnessing just 1% of the world’s super-hot rock resources could yield over 63 terawatts of electricity. While operations at the Oregon site are still in the early phases, Mazama has already secured land for a second development project. The company plans to complete the first site by 2030, at which point it expects to generate 200 megawatts of electricity.
The funding round was led by Centaurus Capital and Doerr Capital. Participation came from major energy players ConocoPhillips and Shell Ventures. Existing investors Khosla Ventures and Gates Frontier also returned, alongside new backers including SiteGround Capital, H. Barton Asset Management, and the Jeffrey and Marieke Rothschild Foundation. Mazama was originally incubated by Khosla Ventures.
Great news for Oregon, but I wonder how much water these super-hot rock systems actually consume? The environmental impact of drilling that deep remains a concern.
15,000 feet in just 15 days is impressively fast. Has anyone else seen drilling stats like this before? It feels almost too efficient compared to conventional methods.
Finally, a realistic alternative to natural gas for AI data centers! This could bridge the gap perfectly while we wait for fusion or better battery storage.
I love the tech, but doubling their estimated capacity from five to ten gigawatts in one year feels risky. I’ll believe the output when I see it on the grid.
Ten times more power than standard geothermal? That is a massive leap. If they can deliver on that promise, it changes everything for grid stability.