Quaise Energy Closes $180M Series B to Commercialize Ultradeep Geothermal Power

Quaise Energy, a utility-scale ultradeep geothermal energy developer, has closed a $180 million Series B equity round, the company announced August 28.

The round included a $35 million investment from Nabors Industries, one of the world’s largest land-drilling contractors.

Quaise Energy uses millimeter-wave drilling technology—developed through more than a decade of research at the Massachusetts Institute of Technology—to reach superhot rock formations deeper than 5 kilometers below the surface, unlocking geothermal heat that can deliver clean, reliable baseload power at utility scale. With the Series B close, Quaise’s cumulative funding reaches $280 million.

Alongside the equity investment, Quaise and Nabors signed a strategic framework agreement covering drilling operations, technology integration, and commercial deployment. The collaboration gives Quaise access to Nabors’ dedicated land rigs and an advanced platform that integrates reservoir modeling, well design, and drilling strategy. The two companies plan to use shared data and operational experience to improve drilling performance, reduce costs, and accelerate project timelines.

“We are unlocking the potential of the most powerful clean-energy resource on Earth,” said Carlos Araque, Chief Executive Officer of Quaise Energy. “Nabors is an invaluable partner in transitioning millimeter-wave drilling to full commercial operations, starting with Project Obsidian and future projects.”

Anthony G. Petrello, Chairman of Nabors Industries, noted, “Ultradeep geothermal has the potential to make clean energy available everywhere. Quaise’s millimeter-wave technology transforms geothermal from a site-specific resource into a global energy solution by reaching superhot rock at depths and temperatures inaccessible to conventional drilling.”

Proceeds will fund Project Obsidian, the world’s first commercial ultradeep geothermal power plant, and the commercialization of Quaise’s millimeter-wave drilling system. The initial Series B close, announced in July 2026, was led by Prelude Ventures and included strategic investment from Japan’s largest power generator JERA and Idemitsu Kosan. BofA Securities and Goldman Sachs advised on the financing.