Quaise Closes $180M Series B for Superhot Geothermal

Rock approaching 500°C turns drilling into a materials problem before it becomes a power resource. Quaise Energy is putting a $180M Series B behind its millimeter-wave drilling technology and Project Obsidian. The final close includes a $35M investment from Nabors Industries, which says it now owns 14% of Quaise on a fully diluted basis.

The round matters because Nabors is already operating a PACE-B rig at Project Obsidian in central Oregon. Its relationship with Quaise now combines equity, drilling equipment, field execution, reservoir modeling, well design, technology integration, and an exclusive drilling-services framework.

Quaise reports $280M in total funding to date. That capital expands the attempt to turn a proven physical concept into reliable wells and grid power, but the difficult proof remains underground: drilling performance, well materials, reservoir behavior, project cost, permitting, and a commercial schedule must work together.

What Quaise Energy Closed

Quaise announced the final close on August 27, 2026. The $180M figure represents the full Series B, not another $180M added in August. The company had announced a $134M first close on July 7, so the final close increased the round by $46M.

Nabors supplied $35M of that increment. Quaise has not identified the investors responsible for the remaining $11M of the final-close increase, and no valuation was disclosed. Prelude Ventures led the first close, with strategic investments from JERA and Idemitsu Kosan; Quaise also said nearly all existing investors, including Safar Partners, participated.

BofA Securities and Goldman Sachs advised on the fundraise. Quaise says the proceeds will fund Project Obsidian and continue commercial development of its millimeter-wave drilling system toward depths beyond 5 km.

Why Nabors Changes the Financing Story

Nabors is not arriving as a financial investor with a distant view of the field. The drilling contractor says its PACE-B rig is operating at Project Obsidian, and its framework with Quaise includes a dedicated land rig, drilling operations, reservoir modeling, well design, drilling strategy, technology integration, and commercial development.

The agreement also includes an exclusivity arrangement for Nabors to provide drilling services on Quaise geothermal projects. If Quaise scales, Nabors could benefit through its equity position and through demand for rigs, engineering, automation, and field services. That alignment puts the contractor learning where the system loses time and wears hardware beside the capital paying for the redesign.

For Quaise co-founders Carlos Araque and Matt Houde, the partnership closes part of the distance between invention and project execution. Araque, the company's President and CEO, spent years in oil-and-gas engineering before serving as technical director at The Engine. Houde, now Chief of Staff, previously worked at AltaRock Energy and managed an ARPA-E-funded program around millimeter-wave drilling.

How Millimeter-Wave Drilling Works

Quaise's hybrid platform begins with conventional rotary drilling and adds a gyrotron-powered system for harder, hotter rock. The gyrotron produces high-power millimeter waves that travel down a waveguide and ablate rock, reducing reliance on complex mechanical equipment in the most extreme downhole conditions.

The concept grew from more than a decade of research at the MIT Plasma Science and Fusion Center. Gyrotrons are established devices in fusion research and industrial applications, but drilling demands sustained energy transmission, material removal, well stability, and reliable operation at depths and temperatures that have not been commercial norms.

Quaise reported drilling more than 100 meters through granite at its central Texas field site in 2025. In July 2026, the company said that program was approaching 1 km, which is progress worth separating from the larger commercial target. A field demonstration can validate equipment and physics without yet proving a long-lived, economical power plant.

Project Obsidian Moves the Test to Oregon

Project Obsidian is located near La Pine in Deschutes County, Oregon, on a federal geothermal lease. The Bureau of Land Management's project record covers a geothermal well pad, a resource-confirmation well, auxiliary storage areas, and freshwater wells. BLM's 2025 categorical-exclusion decision was an interim approval step, with later drilling permits still part of the process.

Nabors describes a planned 50 MW first phase, while Quaise has targeted first grid power by 2030. The companies say later phases could add up to 1 GW of capacity. Those figures describe the ambition and project plan; they do not represent operating output today.

The location offers an unusually studied geothermal setting near Newberry Volcano, but the project still has to confirm the resource and engineer the system around it. Geology does not read investor decks, and a commercial plant cannot choose only one hard problem at a time.

The Market Case for Going Hotter

The U.S. Department of Energy defines superhot geothermal resources as temperatures above 375°C. At those temperatures, water can carry far more heat to the surface, allowing systems to produce several times the power density of lower-temperature geothermal resources.

That potential explains the appetite for next-generation geothermal as power demand rises and grids look for reliable generation that does not depend on weather. It also explains why strategic investors such as JERA, Idemitsu, and Nabors are useful beyond their checks: they bring power-market knowledge, project-development experience, drilling infrastructure, and large-scale operating discipline.

The technical frontier remains demanding. ARPA-E's SUPERHOT program highlights materials that must survive extreme temperatures for years, well designs that handle rapid thermal changes and corrosive fluids, and heat-extraction methods that remain untested in superhot ductile rock. Better access to heat solves only part of the system.

What the $180M Must Prove

Quaise has assembled a substantial financing round around a specific commercial handoff. The company has to move from record-setting drilling tests into repeatable wells, then connect subsurface heat to turbines, contracts, project finance, and electricity that arrives on schedule.

Nabors makes that handoff more credible because it puts field equipment and a major drilling operator inside the same economic relationship. It also makes the next evidence easier to judge. Project Obsidian can now be measured through drilling depth, resource confirmation, well performance, construction milestones, and ultimately the 50 MW first phase rather than through laboratory promise alone.

The Series B buys Quaise time, equipment, and institutional alignment. The heat was already there; Carlos Araque, Matt Houde, and the Nabors crews now have to build the path that lets a power plant use it.