Mazama's 10GW Geothermal Bet on Oregon

A well that reaches 750°F (400°C) doesn't produce steam the way a conventional geothermal plant does. At those temperatures and the pressures found deep underground, water stops behaving like water. It becomes something between liquid and gas — a supercritical fluid — and it can carry far more energy than ordinary steam. That is the target Mazama Energy is drilling toward in Oregon, and on Thursday the startup said it has raised $135 million to get closer to it.

The Series B was oversubscribed, and Mazama said the money will fund horizontal wells in super-hot rock, each one designed to generate 15 megawatts of electricity. The company plans to start generating power sometime next year, according to reporting from TechCrunch.

Drilling Past 10,000 Feet

Mazama's approach depends on depth. The company has drilled past 10,000 feet in 15 days on its way to roughly 15,000 feet, a target it says it can reach with horizontal wells rather than the vertical bores that have defined geothermal development for decades.

At those depths, the rock is hot enough to push water into the supercritical state. Mazama said that state lets each well produce up to 10 times more power than traditional geothermal technologies. The company is betting that the engineering work of reaching that heat — and keeping a well intact once it gets there — is now tractable.

What Supercritical Fluid Buys You

Temperature is the whole story in geothermal. Conventional plants depend on heat that is relatively close to the surface, which limits where they can be built. Mazama is going after rock that is deeper and hotter, and the supercritical fluid it extracts from that rock is the source of its stated advantage.

Because supercritical water absorbs more energy than steam, a single well can carry more of it to the surface. That is the basis for Mazama's 15-megawatt-per-well figure and for the company's claim that its wells can outperform traditional geothermal by an order of magnitude.

The Oregon Site, Revised Upward

Mazama's first site, in Oregon, is capable of producing 10 gigawatts of electricity, the company said. That is a sharp revision from its estimate last year, when investor Vinod Khosla put the site's potential at 5 gigawatts.

The company aims to complete development of that first site by 2030, at which point it says it should generate 200 megawatts. Work there is still in its early stages, but Mazama has already secured land for a second development.

The Investor Roster

The round was led by Centaurus Capital and Doerr Capital. ConocoPhillips and Shell Ventures participated, alongside existing investors Khosla Ventures and Gates Frontier, which returned. New investors SiteGround Capital, H. Barton Asset Management, and the Jeffrey and Marieke Rothschild Foundation also joined.

Mazama was incubated at Khosla Ventures, the firm founded by Vinod Khosla, whose name has been attached to the company since its earliest days.

The Scale of the Resource

The case for drilling this deep rests on how much heat is down there. Tapping just 1% of super-hot rock worldwide could generate more than 63 terawatts of electricity, according to the University of Twente and the Clean Air Task Force.

That figure is a global resource estimate, not a production forecast. It describes what is theoretically available if the technology to reach it works at scale — which is what Mazama's wells are meant to test.

Why Data Centers Are Watching

Enhanced geothermal startups have been advancing their technology quickly, and they are shaping up to be the dark horse in the battle to power AI data centers and other large loads on the grid. Tech companies and data center developers have been throwing their weight behind natural gas, according to the reporting, while geothermal companies push their own approach.

That framing puts Mazama in a race that is less about replacing one fuel with another overnight than about whether a different kind of well can deliver power at all.

What the Money Has to Prove

The new funding buys drilling time and hardware, not certainty. Mazama has set out a sequence: horizontal wells, supercritical fluid, 15 megawatts per well, first electricity next year, full development of the Oregon site by 2030, and 200 megawatts at that point.

Each step depends on the one before it. The company's stated numbers are targets and estimates, and the gap between a resource figure like 10 gigawatts and an operating plant is where geothermal projects have historically stalled. Mazama's answer, for now, is that it has drilled fast and raised enough to keep going deeper.

What It Means for Power Buyers

This is still a single-source story about a private startup's funding and plans, and the numbers involved — 15 megawatts per well, 200 megawatts by 2030, 10 gigawatts for one site — are the company's own. That matters for anyone weighing them against a grid that needs firm capacity.

If Mazama's wells perform as described, the implication is a source of electricity that does not depend on weather or time of day, which is the profile large loads tend to want. If they don't, the $135 million buys a deeper understanding of why — and the super-hot-rock thesis stays a resource estimate rather than a power plant.