Mazama Energy Raises $135 Million to Drill Deeper for Superhot Geothermal

Mazama Energy has raised $135 million in an oversubscribed Series B round to move superhot geothermal toward commercial scale. The financing was led by Centaurus Capital and Doerr Capital, according to TechCrunch.

The investor list blends oil and gas capital, climate venture and family office money. ConocoPhillips and Shell Ventures participated alongside existing investors Khosla Ventures and Gates Frontier. New investors include SiteGround Capital, H. Barton Asset Management and the Jeffrey and Marieke Rothschild Foundation. Mazama was incubated at Khosla Ventures.

The capital will fund horizontal wells in super-hot rock, each built to generate 15 megawatts of electricity. The company says each well will produce up to 10 times more power than traditional geothermal wells. Hotter rock holds more energy, so fewer wells are needed for the same output, according to company materials.

The technical target is 750°F (400°C), heat that turns water into a supercritical fluid at high pressure. Water crosses its critical point at roughly 705°F, becoming a fluid that is neither conventional liquid nor steam, according to Mazama Energy. The company states its pilot demonstration brought that supercritical threshold within reach.

Drilling is already underway. Mazama drilled past 10,000 feet in 15 days on the way to about 15,000 feet. Drilling speed in hard, high-temperature rock is a primary cost driver for enhanced geothermal systems, which make reservoirs in hot rock that lacks natural steam, and horizontal sections add stress on tools and materials.

The first development site is in Oregon. As of September 2026, the company described the site as capable of producing 10 gigawatts of electricity, up from 5 gigawatts estimated for the same site in 2025. Mazama has also secured land for a second development site.

As of September 2026, the company planned to start generating electricity in 2027 and to build the first site to 200 megawatts by 2030. That follows staging described in November 2025, when the company unveiled what was described as the world's hottest enhanced geothermal system and planned to move to commercial projects with horizontal wells, beginning with a 15 MW pilot in 2026, according to Renewable Energy Magazine.

Mazama describes superhot rock geothermal as always-on firm power without fuel and with a small footprint. It states the approach can be built wherever rock is hot enough rather than only where geology allows, and projects that at scale it will compete with the cheapest firm power on the grid.

The broader context here is well construction and plant integration at supercritical conditions more than confirming the resource. Higher energy per well only lowers cost if casing, cement, downhole tools and surface handling survive steady operation, and if flow rates hold without rapid cooling of the rock. Fewer wells per megawatt reduce pad footprint and drilling cost, but concentrate performance risk in each borehole.

In my view, worth flagging is the shift at the Oregon site from 5 gigawatts to 10 gigawatts within a year, paired with participation from two large hydrocarbon investors. That combination suggests growing confidence in subsurface heat and in drilling speed, while giving Mazama access to deep-well operating experience. For grid planners watching firm capacity, the test to monitor is simple. Deliver 15-megawatt-class horizontal wells, hold output, then repeat them to reach 200 megawatts by 2030.