Quaise Energy, which is developing millimetre-wave drilling to reach superhot rock for geothermal power, announced a $134m first close of its Series B on 7 July 2026. Prelude Ventures led. JERA and Idemitsu invested as strategic partners, and nearly all existing investors, including Safar Partners, took part. Additional equity and debt are expected to close soon.
Total funding is now $230m, Quaise said. The company did not disclose a valuation.
“Our ambition is to power civilization with Earth's most compelling energy source.”Carlos Araque, CEO and President, Quaise Energy
What Quaise does
Quaise develops utility-scale superhot geothermal energy. It uses millimetre-wave drilling, developed at MIT, to reach rock at depths and temperatures that conventional drilling cannot economically access. The company says it can reach rock at 300 to 500 degrees Celsius in most places in the world.
At its Central Texas site, Quaise drilled more than 100 metres through granite in 2025 and is nearing 1km of depth, the press release says. The company is working toward depths beyond 5km.
The press release does not give a headcount.
Project Obsidian
The proceeds go to Project Obsidian, which Quaise describes as the world's first commercial superhot geothermal power plant, and to continued development of the drilling system. The project is on federal geothermal leases in Oregon's Deschutes National Forest. The company says construction is under way, that the project has gigawatt-scale potential, and that first power to the grid is targeted for 2030.
Quaise also says the round takes it toward first revenues from off-take partners it has not yet named. Equity and debt for projects are being raised at the same time, with more details expected later in 2026.
Carlos Araque, the company's chief executive, said: "Our ambition is to power civilization with Earth's most compelling energy source." Energy Global quoted him as saying the round takes the company "from field-proven technology to first commercial revenues".
Who invested
Mark Cupta, a managing director at Prelude Ventures, said the firm has backed Quaise since the beginning. Takeshi Kodama, head of JERA Ventures and managing partner at JERA, said millimetre-wave drilling has the potential to make geothermal a truly global baseload resource.
Kei Honda, executive leader of the San Jose office and head of corporate venturing at Idemitsu Americas Holdings, said the investment reflects Idemitsu's commitment to next-generation energy solutions. Parinaz Motamedy, a partner at Safar Partners, said Quaise is unlocking superhot geothermal energy at a global scale.
The funding so far
With $230m raised in total including this round, roughly $96m was raised before the Series B, though the sources do not break down earlier rounds. The $134m is described as a first close, so the final size of the Series B is not yet known.
Energy Global reported the same figures for the round, the investors and the use of funds. Neither source states the company's headquarters or the number of its employees.
Energy Global's report matches the press release on the amount, the lead and the strategic investors.
Company website: quaise.com