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Houston cleantech startup secures $134M to develop ‘superhot’ geothermal plant

deep round

A rendering of a Quaise Energy geothermal plant. Rendering via quaise.com

Houston-based Quaise Energy, a producer of utility-scale geothermal power, raised $134 million in a Series B round to advance its “superhot” geothermal power plant.

Climate-focused San Francisco-based investment firm Prelude Ventures led the round, with participation from JERA Co., Japan’s largest power generation company, and Idemitsu Kosan, one of Japan’s largest energy companies. Nearly all existing investors, including cleantech-focused investment firm Safar Partners, participated in the round.

“We have backed Quaise since the beginning because we believed accessing superhot rock would unlock geothermal energy at a scale the world has never seen,” Mark Cupta, managing director at Prelude Ventures, said in a press release.

The startup expects more equity and debt deals to close “imminently.” Quaise has raised $230 million since its founding in 2018.

Quaise says some of the fresh funding will go toward building the world’s first commercial-scale “superhot” geothermal power plant —Project Obsidian in central Oregon. In addition, Quaise is earmarking money for continued development and commercialization of its millimeter-wave drilling system toward depths exceeding 5 kilometers (about 16,400 feet).

Quaise uses a millimeter-wave drilling system developed at the Massachusetts Institute of Technology to remove rock at depths and temperatures that aren’t economically feasible with conventional drilling. With this technology, Quaise can reach rock at temperatures of around 570 degrees to 930 degrees in most places worldwide, enabling construction of geothermal systems that rival fossil fuels and nuclear energy in power density and that rival renewables in cost.

“Our ambition is to power civilization with Earth's most compelling energy source. This round takes us from field-proven technology to first commercial revenues,” Carlos Araque, co-founder, president and CEO of Quaise, added in the release.

Quaise has demonstrated the capability of its millimeter-wave drilling system at its Central Texas test site, drilling more than about 330 feet through granite in 2025—the first time the technology penetrated basement rock at full scale in the field. The company is approaching a depth of about 3,300 feet at the same site.

Construction of Project Obsidian is underway at Oregon’s Deschutes National Forest. The project, which has the potential to generate gigawatt-scale power, is slated to deliver electricity to the Pacific Northwest grid by 2030.

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

Houston cleantech startup seeks $200M for superhot geothermal plant

seeing green

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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Houston cleantech startup closes $17M round to tap into hot geothermal sector

fresh funding

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.

Houston clean energy events announce keynote speakers from Fervo, Phillips 66

where to be

Two Houston energy institutions will host their signature events this September and have named industry leaders as their keynote speakers.

The Rice Alliance Energy Tech Venture Forum and Greentown Lab's Climatetech Summit kick off Sept. 16. The events are part of Houston Energy and Climate Startup Week and Houston Energy and Climate Week.

The two-day Energy Tech Venture Forum will bring together climatech startups and professionals from around the world to hear pitches, participate in one-on-one office hours and connect with energy innovators.

Sean Maher, chief economist at Phillips 66, will open the forum with a keynote address on the macroeconomic forces shaping the energy industry. Maher also serves as vice president of investor relations at Phillips 66. He previously launched Third Gear Investments, a Houston-based energy investment firm.

Ira Ehrenpreis, founder and managing partner of DBL Partner, which manages more than $1 billion of capital and invests in companies driving social change, will present the keynote on the second day of the forum, Sept. 17. Ehrenpreis is a board member of Tesla and an investor of SpaceX. He will share insights on commercializing breakthrough technologies and what investors are looking for in today's energy innovations.

Applications for the Energy Tech Venture Forum close July 17. Register for the event here.

Fresh off a landmark IPO, Tim Latimer, co-founder and CEO of Houston-based Fervo Energy, will present the keynote at Greentown's Climatetech Summit. Latimer was recently named one of Fast Company's 2026 Visionaries of the Year.

He will be joined by Houston-based SCF Partners' David Baldwin, who will moderate the discussion. The conversation will focus on the timing of Fervo's IPO, what Latimer would have done differently at the early stages of the business, and why the company chose Houston as its headquarters.

The Climatetech Summit will bring together philanthropists, executives and innovators in the energy transition space. Greentown member startups will also present their pitches at the event. Learn more and secure tickets here.

13 Houston energy sector companies make U.S. News' best places to work

where to work

A new U.S. News & World Report ranking of the best employers has named two dozen Houston-based companies among the best companies to work in the South, and more than half are part of the region's booming energy sector.

U.S. News' prestigious "2026-2027 Best Companies to Work For" ratings examine 3,900 public and privately owned companies across 14 industries to help employees and job seekers make decisions about workplaces that may be a good fit.

Each company is rated on a scale of 1-5 across six metrics: quality of pay and benefits; work-life balance and flexibility; job and company stability; physical and psychological comfort; belongingness and esteem; and career opportunities and professional development.

"Job seekers' definitions of 'best' evolve with their needs," said Carly Chase, vice president of Careers at U.S. News. "From new grads in the AI era and seasoned pros seeking a career change, to HR leaders researching organizational trends, the ratings are a central hub that highlights businesses that U.S. News found effectively support their staff."

The number of employers headquartered in the Houston area that made the cut for 2026-2027 has skyrocketed over previous years. A total of 24 local public and private companies made the list this year, up from 16 companies in 2024 and 11 in 2025.

The highest concentration of top employers is located in Houston proper (20), followed by two companies in The Woodlands and one each in Kingwood and Spring.

Several leading Houston energy powerhouses on the list include petroleum corporation Occidental (Oxy) and oil and gas giants Chevron and Phillips 66.

Other energy sector companies on the list are:

  • EOG Resources, Houston
  • Targa Resources, Houston
  • TechnipFMC, Houston
  • Cheniere, Houston
  • Baker Hughes, Houston
  • KBR, Houston
  • CenterPoint Energy, Houston
  • Powell Industries
  • S&B, Houston
  • DXP, Houston
Here are the remaining best Houston-based companies to work for:
  • David Weekley Homes
  • Comfort Systems USA, Houston
  • Corebridge, Houston
  • Cornerstone Home Lending, Houston
  • Farouk, Houston
  • Hines, Houston
  • Insperity, Kingwood
  • HPE, Spring
  • Sterling Infrastructure, The Woodlands
  • LGI Homes, The Woodlands
  • PROS, Houston
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A version of this article originally appeared on CultureMap.com.
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