Mazama Energy, a geothermal startup backed by Khosla Ventures, announced it has raised $135 million in an oversubscribed Series B funding round. The capital will support the company’s efforts to develop horizontal wells in super-hot rock formations capable of producing up to 15 megawatts of electricity per well.

The company plans to begin electricity generation as early as next year at its first site in Oregon. Mazama recently revised its potential output estimate for this site to 10 gigawatts, doubling the previous projection of 5 gigawatts shared by investor Vinod Khosla last year.

Mazama’s approach focuses on enhanced geothermal systems that reach depths of approximately 15,000 feet, where temperatures can reach 750˚F (400˚C). At these conditions, water becomes a supercritical fluid—a state between liquid and gas—that can carry significantly more energy than conventional steam, enabling wells to produce up to ten times more power than traditional geothermal technologies.

This deep drilling capability positions enhanced geothermal as a promising energy source for powering large-scale demands such as AI data centers, which have traditionally relied on natural gas. According to research from the University of Twente and the Clean Air Task Force, exploiting just 1% of the world’s super-hot rock resources could yield over 63 terawatts of electricity.

Mazama is still in the early development phase at its Oregon site but has already secured land for a second project. The company aims to complete the first site by 2030, targeting a generation capacity of 200 megawatts.

The Series B round was led by Centaurus Capital and Doerr Capital, with participation from energy firms ConocoPhillips and Shell Ventures. Existing investors such as Khosla Ventures and Gates Frontier also contributed, alongside new investors including SiteGround Capital, H. Barton Asset Management, and the Jeffrey and Marieke Rothschild Foundation.

Mazama Energy originated as an incubated company within Khosla Ventures, reflecting growing investor interest in advanced geothermal technologies as a clean energy solution.