Mazama Energy Raises $135 Million to Expand Superhot Rock Geothermal Power

Geothermal energy startup Mazama Energy has raised $135 million in a Series B funding round to develop next-generation geothermal power systems using extremely hot underground rock.

The company said the funding will support developing horizontal wells in superhot rock formations that could generate up to 15 megawatts of electricity per well. Mazama plans to begin producing electricity next year from its first project in Oregon.

Using Superhot Rock for Large-Scale Power

Mazama said its Oregon site could produce up to 10 gigawatts of electricity, up from its previous estimate. The company is targeting deeper underground areas where temperatures can reach about 750 degrees Fahrenheit (400 degrees Celsius).

At those depths, water can reach a supercritical state, where it is neither fully liquid nor fully gas. Mazama says this allows the fluid to carry more energy than traditional geothermal steam systems, potentially increasing electricity production from each well.

The company has drilled beyond 10,000 feet in 15 days as part of its effort to reach depths of around 15,000 feet. Mazama expects to complete development of its first site by 2030, with a planned capacity of 200 megawatts.

Geothermal Technology Gains Attention

Enhanced geothermal startups are attracting interest as demand for reliable electricity grows, including from energy-intensive industries such as artificial intelligence data centres. Unlike conventional geothermal projects, these companies are exploring deeper and hotter rock formations to expand where geothermal power can be used.

Research from the University of Twente and the Clean Air Task Force estimates that accessing just 1% of global superhot rock resources could represent more than 63 terawatts of electricity potential, according to a superhot rock geothermal analysis.

Mazama’s latest funding round was led by Centaurus Capital and Doerr Capital, with participation from ConocoPhillips, Shell Ventures, Khosla Ventures, Gates Frontier, and other investors. Khosla Ventures originally incubated the company.