Ultra‑Hot Geothermal: Tapping Newberry Volcano’s Superhot Rock to Power Homes

On the slopes of Oregon’s Newberry Volcano, engineers are building what could become the hottest geothermal power facility on Earth. The project, led by Mazama Energy, has already encountered rock measured at about 629°F (332°C) and aims to push temperatures above 750°F (399°C) to access so‑called “superhot” or supercritical conditions. If successful, the site will begin selling electricity to nearby homes and businesses next year.

What makes superhot geothermal different?

Superhot geothermal relies on rock hot enough that water under high pressure becomes supercritical—neither a typical liquid nor a simple gas—around the water critical point near 705°F (374°C). Supercritical water combines high heat capacity with low flow resistance, allowing a single well to produce roughly five to ten times the energy of a conventional 400°F (204°C) well. That potential could dramatically reduce the number of deep, costly boreholes required for utility‑scale geothermal.

How the Newberry project works

Mazama is using an enhanced geothermal systems (EGS) approach: fracturing hot but dry rock and circulating a working fluid to extract heat. Unlike traditional geothermal that needs natural underground water, EGS injects and recovers fluid in sealed, deep wells so energy can be harvested in many more locations.

To reach deeper, hotter formations, the company cooled drilling equipment using circulating liquid carbon dioxide, enabling crews to drill roughly two miles and find temperatures near 629°F. Mazama plans additional wells next year to reach its >750°F target and initially produce about 15 megawatts, scaling toward 200 megawatts and, in theory, even larger outputs from the broader resource.

Risks and technical hurdles

Accessing and operating at superhot temperatures creates severe engineering challenges. Conventional drilling electronics and materials fail at these extremes. Past experiments have run into molten rock, broken drill bits, and damaged casings—wells in Japan and Italy reached temperatures above 900°F (482°C) but were abandoned when hardware could not withstand the conditions.

“They get fried,” said Sriram Vasantharajan, Mazama’s CEO, describing how standard components behave under superhot conditions.

There is also seismic risk: injecting fluid into rock can trigger earthquakes. Newberry has recorded small tremors (the largest recent event was magnitude 2.5). Experts say seismicity can be managed with careful monitoring, adaptive injection protocols, and engineering controls, and that contamination risk is limited because EGS circulates fluid in deep, sealed wells well below groundwater.

Why it matters

If superhot geothermal can be commercialized at scale, it could transform geothermal from a niche baseload source into a major contributor to clean electricity. The International Energy Agency and other analysts estimate enhanced and superhot geothermal could meaningfully expand geothermal’s share of global power through midcentury. Advocates argue it could reach cost parity with natural gas or solar once technological and operational challenges are resolved—while providing always‑on, low‑emissions power.

Mazama’s initial plan for Newberry—15 MW in the near term and 200 MW as it scales—illustrates a feasible path. Company leaders estimate the broader Newberry resource could theoretically support gigawatts of capacity, though turning that potential into long‑lived, reliable plants will require sustained engineering advances and careful environmental management.