Quaise Energy has closed its Series B round at a total of $180 million in equity financing, bringing the company’s cumulative capital raised to $280 million. The announcement came on August 28, confirming a $35 million investment from Nabors Industries, one of the world’s largest land drilling contractors, which through this stake becomes Quaise’s largest shareholder with a 14% diluted interest.
The funds will be used to develop Project Obsidian in central Oregon: the world’s first commercial superhot rock geothermal plant ever built. The project targets 50 MW of capacity in its first phase, with an ultimate goal of 250 MW. This is not conventional geothermal. Quaise aims to reach depths exceeding 5 km, where rock temperatures allow heat extraction at levels comparable to the best fossil fuel plants — or nuclear ones.
The technology underpinning the entire approach is a millimeter-wave drilling system, developed over more than a decade of research at the Massachusetts Institute of Technology. The operating principle relies on a gyrotron: energy is transmitted deep underground through a waveguide and ablates rock without direct physical contact, reducing the mechanical complexity of downhole components exposed to extreme temperatures. In 2025, at the experimental site in Texas, the system drilled more than 100 meters through granite — the first time the technology had penetrated basement rock at full scale under field conditions. The same site is now approaching one kilometer in depth, a record for any contactless drilling technology.
The initial tranche of $134 million had been led by Prelude Ventures, with strategic participation from JERA and Idemitsu, two of Japan’s leading energy groups. Nabors’ entry marks the final close. The two companies have also signed a strategic collaboration agreement giving Quaise access to a dedicated drilling rig and Nabors’ full technology platform — reservoir modeling, well design, and drilling strategy. The shared objective is to cut operational costs and compress the timeline for the Oregon project.
Superhot geothermal energy — unlike conventional geothermal resources, which are concentrated in volcanic or tectonically active regions — can theoretically be tapped almost anywhere in the world, as long as you can drill deep enough. That is the core premise of Quaise’s bet: making geothermal power independent from surface geology. If Project Obsidian proves the commercial viability of the model, the implications for clean, continuous power generation — without intermittency, without storage — will be tangible and measurable on a global scale.
