Quaise closes $180M Series B as superhot geothermal draws drilling money
Nabors put $35M into the Houston startup's final close, betting superhot rock drilling can move geothermal beyond its 0.4% US generation share.
Quaise Energy closed its Series B at $180 million, the Houston-based startup said during the week of 2026-08-31, with $35 million of that from drilling contractor Nabors Industries. The final close follows an initial $134 million tranche announced on Tuesday (2026-07-07) and brings total funding to $230 million.6,3
The composition of the raise matters more than the headline figure. Nabors is not a venture fund chasing a story; it is a rig company that would have to build and operate the hardware if superhot drilling works at commercial scale. Its $35 million is a bet that the millimetre-wave drilling Quaise is developing can move from laboratory demonstration to something a contractor can deploy across a fleet.6
Quaise's first target is Project Obsidian, a superhot geothermal power plant in central Oregon. The company has already signed a power-purchase agreement for an initial 50 megawatts with an undisclosed customer and is working to sign deals for an additional 200 MW in future capacity. It is also seeking another $100 million in grants and debt for the project, on top of the Series B.3
To understand why investors are writing these cheques, look at the base rate. The United States has about 4 gigawatts of geothermal capacity spread across 99 plants, more than half of them in California. Together they supply 0.4% of national electricity generation.5
That is the number Quaise and its peers are trying to change. The pitch is straightforward: conventional geothermal is limited to places where hot rock is shallow and permeable enough to tap with existing drilling. Superhot rock, by contrast, exists almost everywhere at depth. Researchers estimate that tapping 1% of the world's superhot resources could meet global electricity demand eight times over.1
The investment case has also been helped by the artificial intelligence buildout, which is driving power demand growth and pushing utilities and developers toward an all-of-the-above approach to generation. Enhanced geothermal has been a beneficiary of that shift, catching a wave of investment dollars and renewed policy interest.6
Quaise is not alone in drawing capital. Fervo Energy became the first next-generation geothermal firm to go public in May 2026, netting about $1.9 billion in the process. That exit gave the sector a public-market comparable, which is the kind of thing that makes later-stage private investors more comfortable writing larger cheques.3
The international dimension is broadening too. JERA, Japan's largest power generator, invested in Quaise through its corporate venture capital arm, JERA Ventures, with the two companies set to explore deploying the technology in Japan. That is a useful signal: a utility with a large LNG import book and a stated decarbonisation target is looking at superhot geothermal as a potential domestic baseload source.4
In Taiwan, Baseload Power Taiwan and state-owned CPC Corporation signed a memorandum of understanding to accelerate geothermal development, with an initial focus on the Tuchang project in Yilan County. That deal is smaller and more conventional, but it points in the same direction: Asian utilities and state oil companies are putting exploration dollars into geothermal after years of treating it as marginal.2
Where this gets harder is delivery. Superhot drilling has never been demonstrated at the depths, temperatures and durations required for a commercial power plant. Quaise's millimetre-wave approach is a departure from conventional rotary drilling, which means the supply chain — rigs, bits, downhole tools, casing — has to be adapted or rebuilt. Nabors' investment gives the company access to operational expertise and hardware, but it does not de-risk the physics.6
There is also a financing gap between the Series B and the project. Quaise has raised $180 million in equity, but it is still $100 million short of what it says it needs for Obsidian, and that shortfall is to be filled with grants and debt rather than more venture money. Grants are competitive and debt requires a project that banks can underwrite.3
For energy traders and portfolio managers, the relevance is not immediate. Superhot geothermal will not move Henry Hub or JKM this year. But the direction of travel matters for long-dated power curves. If even a fraction of the 200 MW Quaise hopes to contract materialises, it adds firm, dispatchable, zero-fuel-cost capacity to a grid that is currently short of exactly that.3
The nearer-term signal to track is whether Quaise converts its 50 MW PPA into a financial close for Project Obsidian, and whether it signs the additional 200 MW. Until then, the $180 million is a statement of intent from a drilling contractor and a Japanese utility, not a proven cost curve.3,4