Mazama Raises $135 Million to Push Superhot Geothermal Wells Toward 2027 Test

Interesting Engineering documents Mazama Energy’s $135 million raise as the financing push behind a hotter and deeper geothermal test in Oregon, where the company wants to turn extreme underground heat into repeatable power generation.

The capital, announced September 17, is meant to accelerate commercial work on superhot rock geothermal energy at Newberry, including Project Athena and the U.S. Department of Energy-supported Project Ceres.

Mazama is aiming for a power-generation demonstration in 2027, putting the funding round on a defined technical clock rather than leaving it as a general climate-technology pledge.

The engineering target is rock at 750°F, or 400°C. Mazama frames that threshold as the point where one borehole may produce as much electricity as about 10 standard geothermal wells operating near 390°F, or 200°C. At 750°F, water can shift into a supercritical state, which gives the circulating fluid a denser energy load before it returns to equipment at the surface.

Newberry already gives the company a proof point.

In 2025, Mazama created an engineered geothermal system there that reached 629°F, or 331°C, and demonstrated reservoir creation, underground connectivity and heat recovery.

Engineered geothermal systems differ from conventional geothermal projects because they create pathways through hot rock instead of depending only on naturally occurring reservoirs.

Project Athena is now pushing that platform deeper.

Mazama’s second well reached 10,350 feet in 15 days in September, roughly 80% faster than the well drilled in 2025.

The company is extending the well about one mile farther to chase the 750°F target.

Chief executive Sriram Vasantharajan described the work at Newberry as a move from individual technical pieces toward an integrated system with more speed, efficiency and scale.

The proposed operating model is not only about hotter wells.

Mazama says its approach could use 75% less water and require 80% fewer wells than conventional geothermal developments, reducing surface infrastructure and the physical footprint of each project.

The technical program ties together three problems that usually sit in separate workstreams: keeping equipment alive in extreme heat, opening usable flow paths inside dry hot rock and pulling enough thermal energy from that artificial reservoir to run a power plant.

The Series B round was oversubscribed, with Centaurus Capital and Doerr Capital at the front of the investor group.

Strategic and venture participants included ConocoPhillips, Shell Ventures, Khosla Ventures and Gates Frontier, giving the company backing from energy incumbents and climate-focused investors.

Part of the money will fund Project Ceres, which is designed to advance horizontal wells in superhot rock.

That project is targeting 15 megawatts of electrical capacity per well and is also expected to show power generation in 2027.

Beyond the two named projects, Mazama wants outside validation that Newberry can support a geothermal resource above 10 gigawatts.

It is also reviewing other sites in the United States and overseas as it tries to move from a high-temperature demonstration toward multi-gigawatt geothermal developments.

The remaining test is execution at scale.

The financing gives Mazama money for deeper drilling, horizontal well work and certification, but the source evidence still points to 2027 as the moment when Newberry must show that extreme heat can be converted into dependable generation rather than only measured underground.