seeing green

Houston cleantech startup seeks $200M for superhot geothermal plant

Quaise Energy is developing Project Obsidian, a superhot geothermal plant in central Oregon. Rendering via quaise.com.

Houston-based Quaise Energy is looking to raise $200 million to support the development of a 50-megawatt superhot geothermal plant in Oregon.

The company is seeking $100 million in Series B funding, plus an additional $100 million from grants, debt and project-level finance, a representative from the company tells Energy Capital. Axios first reported the news late last month.

Quaise specializes in terawatt-scale geothermal power. It is known for its millimeter-wave drilling technology, which was developed at MIT.

The company's Project Obsidian development in central Oregon will combine conventional drilling with its millimeter-wave technology. Quaise says the project, targeted to come online in 2030, could be the first commercial plant to operate in superhot rock, a more efficient and abundant resource, but one that requires more advanced and durable drilling technology.

Quaise says Obsidian would initially generate 50 megawatts of "always-on" power and would be designed to add 200 megawatts as additional wells are developed. A power-purchase deal has already been signed for the initial 50 megawatts with an undisclosed customer.

A representative from the company says Quaise would also use the funding to continue advancing its millimeter-wave technology and prepare it for commercialization.

Last year, the company drilled to a depth of about 330 feet using its millimeter-wave technology at its field site in Central Texas.

“Our progress this year has exceeded all expectations,” Carlos Araque, CEO and president of Quaise Energy, said at the time. “We’re drilling faster and deeper at this point than anyone believed possible, proving that millimeter-wave technology is the only tool capable of reaching the superhot rock needed for next-generation geothermal power. We are opening up a path to a new energy frontier.”

Canary Media reports that Quaise plans to drill to nearly 3,300 feet later this year and to deploy its millimeter-wave technology at its power plant in 2027.

Quaise raised $21 million in a Series A1 financing round in 2024 and a $52 million Series A in 2022. Major investors include Prelude Ventures, Safar Partners, Mitsubishi Corporation, Nabors Industries, TechEnergy and others.

Quaise was one of eight Houston-area companies to appear on Time magazine and Statista’s list of America’s Top GreenTech Companies of 2025.

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A View From HETI

The company develops ultra-high-temperature tools to withstand the heat of geothermal reservoirs. Photo via hephaeet.com

Houston-area startup Hephae Energy Technology Corp. has closed a $17.8 million Series A financing round to commercialize its geothermal technology.

The round was co-led by Pennsylvania-based Susquehanna Sustainable Investments, which invests in early-stage climatech companies, and Copenhagen-based Underground Ventures, which focuses on geothermal energy startups. Alfa8, Baruch Future Ventures, Centaurus Capital LP, Elemental Impact, Exa Ventures, Future Ventures, Grantham Foundation for the Protection of the Environment, New System Ventures and True North Institute joined the round, along with existing Houston-based investor Nabors Industries. Hyphae reports in a news release that the Series A round brings the company's total capital raised to $24.7 million.

Hephae develops ultra-high-temperature downhole sensing, measurement, communications and control systems that can withstand the heat of geothermal sites, which are hotter and deeper than traditional oil and gas reservoirs. The company's Pandora210 system can operate at up to 400 degrees Fahrenheit.

Hephae reports that it plans to use the new funding to commercialize its Pandora210 tool and to launch research and development into systems that can withstand temperatures of up to 570 degrees Fahrenheit. Houston-based Fervo Energy, for instance, recently tapped its hottest geothermal well to date in western Utah, showing temperatures above 555 degrees Fahrenheit.

"Commercial deployment represents a major milestone in our mission to scalable, always-on, emission-free power globally, with a world-class team to tackle this problem," Steve Krase, CEO of Hephae Energy Technology, said in the release." This investment enables Hephae to transition from development to scale, delivering the ultra-high temperature drilling technologies needed to support the rapid growth of the geothermal industry in the US and international markets."

Hephae has been collaborating with Fervo Energy in the field. The company told the Houston Business JournalHouston Business Journal this spring that it expected its Pandora210 technology to be deployed at its Utah sites.

“Fervo is encouraged by the early progress of our collaboration with Hephae, whose novel high-temperature innovations have the potential to contribute positively to EGS economics, unlock higher-energy geothermal resources, and further cement the competitiveness of next-generation geothermal power," Elliot Howard, director of drilling and completions at Fervo, added in the release.

As the geothermal industry continues to scale, Hephae says it aims for its technology to help companies "unlock hotter, deeper resources that result in lower produced energy costs."

The Spring-based startup was founded in 2020 by CEO Steve Krase and CTO John Clegg. Krase previously launched Navigate Energy Services, which was acquired by Nabors in 2013. Clegg is also an industry veteran and has held numerous leadership positions at energy companies, including Weatherford, NOV, Schlumberger and others.

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