Mazama, a geothermal startup with backing from longtime cleantech investor Vinod Khosla, says it has drilled into rock hot enough to upend the conventional wisdom about providing 24/7 clean electricity using volcanoes to supercharge water. The company is positioning its “superhot rock” approach as a way to provide grid-scale, round-the-clock power that can keep data centers humming and shore up the gap left by thermal generation, but without carbon or fuel risk.
Why Superhot Rock Alters the Grid Math for 24/7 Power
Temperature is destiny in geothermal. Heat carried by a mass of water or steam increases rapidly as rock temperatures reach levels approaching 400°C and higher. Analyses by the Clean Air Task Force and academic work examining superhot rock energy show that wells above roughly 375–450°C should be able to produce an order of magnitude more power than traditional geothermal wells, which work well enough at water temperatures still five or six times higher than those used for spent fuel storage.
Mazama’s most recent well is aimed at that regime. The goal is to extract at least 25 megawatts from a single borehole — as much as two or three times what the best enhanced geothermal projects can do today. The internal modeling indicates places where there might be eventual room for multiple wells to tap in at gigawatt-scale plants. Khosla has stated each site could host around 5 gigawatts, should the resource pan out.
That power density matters. With capacity factors regularly in the 85–90% range, geothermal can offer the always-on backup that wind and solar do not. It’s why hyperscalers are inking geothermal deals for data centers; to wit, Google has a deal for next-gen geothermal in Nevada. If superhot systems get out of the lab and up to industrial scale, they could deliver 24/7 clean power — but without the expanse of land or storage profile other options might demand.
How The Technology Works To Tap Superhot Rock Energy
Enhanced geothermal systems (EGS) develop engineered reservoirs in hot, impermeable rock and circulate fluid to extract heat. What Mazama is after, simply put, is the superhot end of EGS, at which point the working fluid nears a condition known as supercritical — an incredibly energy-dense state that can reduce the number of wells and volume of water needed to operate.
It is not an easy task to drill and operate in 400°C rock. Drilling with sandstone cutters impacts designs, which are programmed as being suitable for an 80-acre lateral to minimize the risk of one becoming stuck. The industry has been pushing high-temperature drilling fluids, cement, packers, and logging tools; managed pressure drilling and better PDC bits are expanding the envelopes. Mazama’s discovery indicates those pieces are fitting together more quickly than many had anticipated.
The company says it can reduce water use by 75% compared to traditional geothermal loops. That follows physics: hotter reservoirs pack more energy per kilogram of fluid, so less fluid can be circulated for the same output. With fewer wells and smaller surface plants, there is also less of a footprint on the site in the interim, which helps projects connect into existing substations — a particularly good fit when near retiring fossil facilities.
Cost And Scale Signals For Superhot Rock Geothermal
The U.S. Department of Energy’s Enhanced Geothermal Shot aims to reach $45/MWh by 2035. If high output per well does come to pass, superhot rock could beat that mark sooner. At around 450°C, energy per well becomes roughly 10x higher than for resources at 200°C, which would provide a step change and spread drilling costs and surface facilities over a much larger amount of generation. Its backers say that puts all-in costs competitive with modern gas power, without fuel volatility or emissions.
Resource potential is not the issue. For years, the U.S. Geological Survey has designated the Great Basin a “geothermal hotspot,” and calculated that EGS installations in that region alone could meet substantial portions of national demand. By aiming for deeper, warmer rock, superhot projects could expand that promise to more regions and into geologies once dismissed as too cool or impermeable.
The timing is fortuitous. The International Energy Agency is forecasting up to a doubling of worldwide power demand underwritten by data centers, A.I., and crypto from current levels to as much as 1,000 TWh per year by the middle of this decade. Utilities require reliable, 24/7 power inside existing grid boundaries. If Mazama and its peers can stand up multi-hundred-megawatt blocks of load near demand centers, they will have ready buyers.
Competition And Risks In Emerging Superhot Rock
Mazama is not alone. Fervo Energy has demonstrated modern EGS with horizontal drilling and fiber optics, and is scaling to hundreds of megawatts. Eavor is commercializing closed-loop “radiator” systems, which do not exchange fluids with the formation. The company is working on so-called millimeter-wave drilling, which can penetrate to depths and temperatures previously unattainable. Each possibility has unique technical and permitting risks — and each, if it works, grows the same clean baseload pie.
Special challenges face superhot rock: materials and sensors that can last months at 400°C, pathways for flow without excessive induced seismicity, and turbines designed for high-enthalpy fluids. Funding will be contingent on multi-month flow tests with parallels and downward pressure on cost per foot drilled. Look for upcoming milestones to cover long-running production runs and transition into surface power blocks.
What To Watch Next As Superhot Rock Projects Scale
Near-term catalysts include Mazama’s record-temperature well continuing to return heat-flow test results, follow-on wells announced from the same pad, and off-take agreements that establish bankability.
Regulation, too, is progressing; both federal and state agencies are developing ways for EGS to move forward that include the use of water and monitoring for seismicity while also decreasing timelines.
And if Mazama can make the case that they know how to turn a single borehole into 25 MW and replicate it, superhot rock suddenly goes from lab curio to grid asset. Amid a decade of tight power markets and escalating demand for electricity, that change would rank as one of the most pivotal shifts in clean power.