Quaise Raises $180M to Back Superhot Geothermal

Estimated reading time: 5 minutes · Last updated: 31 August 2026

Quaise Energy has closed a $180 million Series B round, including a $35 million investment from Nabors Industries, to accelerate commercial development of superhot geothermal power and fund Project Obsidian. The financing brings Quaise’s total disclosed funding to $280 million and backs its millimeter wave drilling effort to reach depths in excess of 5 km. As first reported by Interesting Engineering, the round’s first close was announced in July 2026 and was led by Prelude Ventures with strategic investments from JERA Co., Inc. and Idemitsu Kosan. Quaise says the funds will move Project Obsidian toward demonstration of a commercial superhot geothermal plant.

“We are unlocking the most powerful clean [energy] source on Earth, and the Series B signals deep conviction across a wide range of investors,”

Carlos Araque, CEO and President, Quaise Energy

Who invested and what the cash will do

The Series B round announced in late August 2026 raised $180 million in equity and included a $35 million direct investment from Nabors Industries (NYSE: NBR). The financing follows a first close in July 2026 led by Prelude Ventures and lists strategic participants JERA Co., Inc. and Idemitsu Kosan among its backers. BofA Securities and Goldman Sachs & Co. LLC acted as advisors on the transaction, and Quaise says the proceeds will fund Project Obsidian and further commercialisation of its drilling system.

Quaise has also formalised a strategic framework with Nabors covering drilling operations, technology integration and commercial development. Under that framework Quaise gains access to a dedicated land rig and Nabors’ integrated platform for reservoir modelling, well design and drilling strategy. Quaise frames the package as a way to accelerate deployment and reduce drilling costs through shared data and operations.

The technology: millimeter wave drilling aimed beyond 5 km

Quaise is developing a millimeter wave drilling approach intended to reach superhot rock at depths conventional rotary rigs rarely access. The company says the system targets depths in excess of 5 km, where temperatures and rock properties differ materially from shallow geothermal fields. Reaching those depths is the technical core of Quaise’s claim: if millimeter wave drilling can be operated reliably and at acceptable cost, it would open resources that today are considered uneconomic with standard drilling.

The strategic framework with Nabors is presented as a way to combine Quaise’s drilling technology with a large contractor’s operational capacity. Nabors’ platform is described in the announcement as including reservoir modelling and well design tools that Quaise expects to integrate with its drilling programme. The effect, the companies say, should be faster learning, improved drilling performance and lower unit costs as the programme scales toward the pilot plant.

Project Obsidian: a planned demonstration in Central Oregon

Project Obsidian is presented as Quaise’s demonstration plant and is described in the company announcement as the world’s first commercial superhot geothermal power plant. The project is being developed in Central Oregon, southeast of Bend, and its stated purpose is to prove that superhot resources can be drilled, produced and converted to electricity at commercial scale.

Quaise frames Obsidian as a testbed: the company will demonstrate drilling to superhot rock, reservoir behaviour at those temperatures and the complete chain for electricity generation. The announcement says success at Obsidian could change geothermal from a location-dependent resource into one deployable across a far wider geography, though it does not specify a commercial commissioning date for the plant.

Why this funding matters for scaling geothermal

Quaise positions the round as stepping beyond pilot R&D into industrial-scale demonstration. The $180 million raise, plus the operational tie-up with Nabors, is intended to address three bottlenecks simultaneously: deeper, higher-temperature drilling; integrated well design and reservoir modelling; and data-driven cost reduction through repeated operations. The company argues that if those elements come together, superhot geothermal could be developed at gigawatt scale in places that lack conventional geothermal resources.

The announcement highlights strategic industrial partners from Japan and a major drilling contractor rather than only venture capital, which signals investor interest in fielding hardware and operations, not just laboratory proof-of-concept. That mix matters because moving from a single demonstration well to multiwell commercial plants requires both capital and established drilling supply chains.

How the case for and against rapid scale-up breaks down

The bottom line

The $180 million Series B and the strategic tie-up with Nabors mark a move from lab-stage claims toward field demonstration for Quaise. Project Obsidian is positioned as the company’s real-world test of millimeter wave drilling to depths above 5 km and a commercial pathway for superhot geothermal. The financing and industrial partners reduce some barriers to scaling, but the programme still faces technical, cost and permitting risks that will determine whether superhot geothermal can broaden geothermal’s geographic reach.

What to watch

• Watch for Project Obsidian’s permitting milestones; no date has been set.
• Watch for demonstrations of millimeter wave wells drilled beyond 5 km depth; no date has been set.
• Watch for commercial agreements or offtake announcements with utility partners; no date has been set.