Superhot Rock Drillers Advance Technology to Rival Oil and Gas

The geothermal energy sector has the potential to be just as big as the oil and gas sector, if you ask Carlos Araque.

“The reason for that is that the resource truly is everywhere if you can go deep enough and the resource is reliable and firm.… Other than nuclear, there’s nothing like it that truly has a global scale,” he told Oil and Gas Investor.

Araque is CEO and co-founder of Quaise Energy, one of the few companies targeting superhot geothermal resources with specialized drilling equipment. He is building on his expertise in the oilfield services sector to transform geothermal amid the drive for lower-carbon energy.

Araque’s hopes are high for a sector that accounts for less than 0.5% of total electricity generation in the U.S., according to the U.S. Energy Information Administration, and faces stiff competition from natural gas and renewables.

But, “If you can get the oil and gas people to look at geothermal with the eyes that they look at an oil and gas project, I think you fundamentally change the trajectory of the energy transition,” he said.

Oil and gas companies are taking notice of the potential of geothermal energy. Seeing the synergies between the sector and geothermal drilling, several have doled out dollars backing geothermal initiatives as well as formed partnerships with startups and established geothermal developers.

The attention to geothermal energy, including from the administration of President Donald Trump, comes as the U.S. eyes an anticipated surge in electricity demand driven by data center growth, a rise in electrification and the return of manufacturing amid a domestic reshoring push. Users of electricity are craving affordable, reliable and lower-carbon baseload power—something that backers of geothermal say they are capable of delivering.

Geothermal energy harnesses heat below ground using wells drilled into hot reservoirs. Conventional geothermal does not require much engineering to capture heat because it’s closer to the surface, with naturally occurring fractures and fluid, such as in volcanic areas. But companies like Quaise and are targeting deeper and hotter geothermal resources as part of next-generation geothermal efforts.

“That’s what it takes to cover the world in industrial-scale geothermal power,” Araque said.

Targeting superhot rock

Modeling by the Clean Air Task Force (CATF) indicates harnessing only 1% of the world’s superhot rock geothermal could generate 63 terawatts of clean firm power. That equates to 8 times more than the world’s current total electricity capacity.

In the U.S. alone, tapping 1% of superhot rock geothermal potential could produce
4.3 terawatts of clean firm power. The CATF said that is enough energy to power New York City 687 times over.

Geothermal baseload production in the U.S., however, is currently limited to about 4 gigawatts, according to the U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E). But the U.S. is taking steps to seize superhot rock opportunities.

Earlier this year, ARPA-E unveiled a new program that allocates $30 million to efforts focused on the development of superhot rock resources. The Stimulate Utilization of Plentiful Energy in Rocks through High-temperature Original Technologies (SUPERHOT) program focuses on modification of conventional well designs or novel designs, materials, and materials systems that satisfy requirements to survive superhot conditions.

The program aims to “develop robust geothermal well construction capable of a 15-year operational life and enable transfer of heat from the surrounding geologic formation to the well,” according to ARPA-E. The agency is targeting projects that unlock geothermal resources at temperatures greater than 375 C and pressures greater than 22 megapascals.

“Geothermal is a reliable and secure baseload power source, but today we are only able to access a fraction of the energy it can provide,” Evelyn N. Wang, who served as director of ARPA-E at the time, said in a news release. “SUPERHOT projects can change that and allow access to hotter reservoirs to create more domestic flow of energy onto America’s grid.”

Enhanced geothermal systems and closed-loop geothermal systems at subsurface temperatures above 400 C are used to develop superhot rock geothermal resources using “very high-enthalpy systems where the circulating fluid reaches supercritical conditions,” the DOE said in its Pathways to Commercial Liftoff: Next-Generation Geothermal Power report. The systems being deployed in these conditions can be extremely efficient, the report said, but technologies that enable this potential are still in development.

Quaise is moving its millimeter wave drilling technology into the field demonstration phase in 2025, having already publicly showcased system integration tests of a full-scale drilling rig with its system. In late 2026, plans are to have the technology operating in a commercial project at a power plant.

Eliminating the drillbit

Going to depths as deep as 12 miles and to temperatures up to 500 C is not without challenges. Among the complexities is the size of drilling rig needed to support piping and wellbore integrity, according to Araque.

“Lucky enough for us, the drill pipe we use is a lot lighter than the drill pipe the oil and gas industry uses,” Araque said. “Some of the big oil and gas drilling rigs are perfectly suitable for the weight of pipes that we use. Other things that pop up is that you start getting into issues with wellbore integrity. Very deep holes at some point will collapse on themselves. So, you have to case them. You have to support and reinforce them. And the deeper you are, the harder that gets.”

But the fundamental problem in deep geothermal drilling today has less to do with those challenges and more to do with actually destroying the rock, according to Araque.

Geothermal drillers use some of the same drilling equipment as the oil and gas sector, but drillbits can quickly wear when used in hotter, harder and more abrasive geothermal drilling conditions.

“That process of drilling a little bit, replacing the drillbit, drilling a little bit more with a drill bit that’s wearing every 10 to 20 hours gets very expensive and at some point, it becomes impossible. You just can’t do it anymore.”

With millimeter wave drilling, Quaise aims to flatten the cost curve by eliminating the drillbit.

Instead of using conventional downhole techniques with drilling mud to break rock, remove materials, stabilize the borehole and manage temperature and pressure, energy matter interaction takes place as high-powered radiofrequency energy is used. For millimeter wave technology, used by Quaise, microwaves are sent downhole via a gyrotron.

The gyrotron—a device that emits intense electromagnetic waves and is commonly used in nuclear fusion as a source of millimeter wavelength radiation—allows the driller to remove rock. The rock is heated with the gyrotron, causing the rock to melt and vaporize to create deep holes to extract geothermal energy.

“What we’ve done with millimeter wave drilling is to extend the capabilities of drilling rigs. We start with conventional drilling, no changes,” Araque explained. “We’re going to drill down to where it starts to get very expensive. And once it does, once it starts to trend above $2,000 per meter, we’re going to switch to millimeter wave drilling. Millimeter wave drilling is a very different way to drill. It doesn’t require a drill bit. There’s nothing to wear.”

The estimated cost to drill a 10-km hole ranges between $10 million and $20 million, he said, noting that’s on the high side of an onshore oil well but the low side of an offshore oil well.

“We want to access heat as a resource on economic parity with oil and gas. We want these wells to produce as much energy as the equivalent oil well if you had drilled for oil, because that’s really what’s going to get the oil and gas industry interested in this business.”

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