Mazama Energy has completed a US$135mn fundraising to help scale the world’s hottest engineered geothermal system, a financing supported by some of the world’s major oil and gas corporations.
Lead Investors included Centaurus Capital and Doerr Capital, with strategic participation from oil majors ConocoPhillips and Shell Ventures, alongside other backers including Gates Frontier and the Jeffrey and Marieke Rothschild Foundation.
Mazama holds the record for the hottest engineered geothermal system (EGS) ever built.
“The breakthrough in superhot geothermal is turning extreme heat into a repeatable, economic power system,” said Sriram Vasantharajan, CEO of Mazama Energy.
In 2025 at Newberry, Oregon, the company created an engineered geothermal system at 629°F (331°C), proving reservoir creation, connectivity and heat recovery.
It is now pushing toward even hotter targets — its second well, Project Athena, reached that same 10,350-foot depth in 15 days during September, about 80% faster than the 2025 well, and is drilling a mile further down toward 750°F (400°C).
“At Newberry, we have demonstrated the critical pieces together: extreme-temperature drilling, reservoir creation and heat harvesting, at temperatures no other engineered geothermal system has achieved,” said Vasantharajan.
“We are now driving that integrated system toward greater speed, efficiency and scale. That is the foundation for commercial superhot power.”
According to Mazama, reaching 750°F (400°C) delivers up to 10 times the power of a conventional 390°F (200°C) well, owing to the much higher energy density of supercritical water and improved reservoir productivity.
This allows the company to deliver projects using 75% less water and drilling 80% fewer wells than conventional geothermal developments.
Mazama said its technology has the potential to significantly improve the viability and permitting prospects of geothermal projects across a wide range of regions, reducing both surface infrastructure requirements and overall project footprint.
“Unlocking superhot rock geothermal requires solving three interconnected challenges: reaching extreme temperatures without compromising the equipment, creating a productive reservoir where none exists naturally, and efficiently extracting heat to generate and sustain power,” a company statement read.
“Mazama has spent the last several years developing these capabilities into a single integrated system, paving the way toward delivering carbon-free, baseload power competitive with fossil fuels.”
The new financing will fund Project Ceres, supported by the US Department of Energy, to advance horizontal well development in superhot rock toward a 15 MWe of capacity per well and demonstrate power generation in 2027.
Athena and Ceres are the near-term ‘proof points’ for a much larger ambition, the statement added.
“Mazama is targeting independent certification of more than 10 GWe of resource potential at Newberry alone, while evaluating additional sites in the United States and internationally as it builds toward multi-gigawatt-scale developments,” it noted.
“Mazama’s goal is to make superhot rock geothermal a scalable source of firm power to address rising electricity demand, affordability and energy security around the world.”
A quote from ConocoPhillips was also included in the Mazama statement: “We are pleased to support Mazama as it advances a differentiated pathway to commercial scale ultra-high-temperature geothermal based on demonstrated field performance.”