Hephae raises $17.8M Series A to drill geothermal's hottest rocks
What's the deal? Hephae Energy TechnologyDealroom has a profile for this one. Try Dealroom →, a high-temperature geothermal drilling startup, has closed a $17.8 million Series A, co-founder and chief executive officer Steve Krase told Axios Pro. The round was co-led by Susquehanna Sustainable InvestmentsDealroom has a profile for this one. Try Dealroom → and Underground VenturesDealroom has a profile for this one. Try Dealroom →.
The details: Participating investors included alfa8Dealroom has a profile for this one. Try Dealroom →, Baruch Future VenturesDealroom has a profile for this one. Try Dealroom →, Centaurus CapitalDealroom has a profile for this one. Try Dealroom → LP (John Arnold's family office), Elemental ImpactDealroom has a profile for this one. Try Dealroom →, Exa VenturesDealroom has a profile for this one. Try Dealroom → (Chris Anderson's family office), Future VenturesDealroom has a profile for this one. Try Dealroom →, the Grantham Foundation for the Protection of the Environment, New System VenturesDealroom has a profile for this one. Try Dealroom →, and True North Institute. The Spring, Texas-based startup, founded in 2021, has now raised $24.7 million in total.
How it works: Standard drilling systems use computing, robotics, and sensors to measure the process, but the electronics fry when rocks exceed 175 C. Hephae has engineered a system that shields those components, enabling drilling up to 210 C, with next-generation tools targeting over 300 C.
Why now? Interest in the geothermal supply chain is growing after Fervo Energy's IPO. Hotter rocks can deliver more energy, lowering costs — but companies struggle to tap them with standard tech.
What's the endgame? Hephae rents its systems to developers at temperature-based day rates and counts Fervo and Mazama as customers. It plans to spend the proceeds building out a dozen drilling systems and on R&D for higher temperatures. The company says its systems can save as much as $1 million per well through improved efficiency.
What they're saying: "We're the only ones working on this," Krase said. "This market is just too small for the big guys to focus on it."
The signal: Geothermal is riding a wave of data center demand, bipartisan support, and new tools after years as a clean energy niche. It could meet up to 15% of global electricity demand growth by 2050, according to the International Energy Agency — and reaching the hottest rocks is central to that promise.
Read more: Axios
Image credit: ThinkGeoEnergy
