Mazama Energy has closed a $135 million oversubscribed Series B round aimed at advancing its super-hot-rock geothermal technology. The recent capital infusion will support the startup’s work developing horizontal wells that tap into extremely hot subterranean rock—engineered for high output power generation.
With this funding, Mazama is targeting geothermal wells capable of delivering 15 megawatts each. The company plans to begin electricity production next year, revising earlier estimates upward: its first project in Oregon is now projected to yield up to 10 gigawatts of electricity, doubling a previous forecast of 5 gigawatts.
Super-Hot Rocks: What Makes Them Game Changers
Unlike conventional geothermal systems that rely on shallower, lower-temperature conditions, super-hot-rock geothermal operates much deeper—on the order of 15,000 feet or more. At such depths, rocks reach around 400 °C (750°F), forming supercritical fluids that aren’t quite liquid or gas. These fluids carry significantly more thermal energy than standard steam-based methods, enabling wells to produce up to ten times more electricity per well.
Mazama has already demonstrated rapid drilling, having passed the 10,000-foot mark in just 15 days as it pushes toward deeper, hotter geological formations. The promise carried by this approach is substantial: tapping even 1% of super-hot rock globally could unlock more than 63 terawatts of potential electricity generation.
Strategic Moves & Ambitious Timelines
Mazama plans to finalize its Oregon site by 2030, aiming to produce 200 megawatts from that location. Alongside this, the company has secured land for a second development site to scale its operations.
This Series B round was led by Centaurus Capital and Doerr Capital. Major energy players like ConocoPhillips and Shell Ventures also invested, alongside returning backers including Khosla Ventures and Gates Frontier. New participants in the funding include SiteGround Capital, H. Barton Asset Management, and the Jeffrey and Marieke Rothschild Foundation.
Mazama was incubated within Khosla Ventures, and its progress reflects growing momentum in enhanced geothermal technologies—especially as energy demand soars, driven in part by AI data centers and climate-driven power needs.
Analytical Angle: This investment signals that enhanced geothermal is emerging from niche status toward being a serious contender for baseload clean energy. The scaling efforts underway at Mazama—with ambitious drilling depths, upgraded power projections, and high-profile investors—show that super-hot-rock geothermal could help diversify the decarbonization toolkit. What to watch: whether Mazama can overcome technical and permitting challenges, deliver on its timeline, and prove that supercritical geothermal remains economically viable at scale.
