As we descend into hotter, deeper tiers, the process shifts from pressure-driven to density-driven stimulation. With larger density contrasts between the injected water and pore fluid in the rocks, density takes the lead. The deeper we go, fracturing becomes easier, not more challenging, and reduces the need for massive pumping fleets.
It all results in a superhot subterranean network sweeping away 10-100x more heat than all other forms of geothermal. We are sending water coursing through engineered permeability, harnessing Earth’s most abundant energy and powering the next century of global innovation.
Supercritical fluid dynamics are thus the key to superhot geothermal completions. Water above and 22 mega pascals (3191 psi) enters a supercritical state with liquid-like density and gas-like viscosity. The water that is injected into a hot, supercritical reservoir is thus much denser than the surrounding superhot fluid. The injection of relatively cool water into superhot rock creates and widens fractures increasing permeability without increased pumping pressure.
A short Quaise video (below) describes how conventional and millimeter wave drilling can be combined to reach superhot geothermal energy sources.
Keep in mind that superhot (300-500 deg. C) energy can be reached with conventional drilling at sites with high geothermal gradients. These “tier 1” sites will be the first targets (second video below).
HOUSTON (7/22/2025) – “Quaise Energy, a leading developer of grid-scale superhot geothermal energy, today announced it has successfully drilled to a depth of 100 meters using its proprietary millimeter wave technology at its field site in Central Texas. This achievement sets a record for millimeter wave drilling and marks a major step forward in unlocking the Earth’s vast geothermal energy as a scalable, baseload energy source.“
Prior to this year, millimeter wave drilling had only been demonstrated in the laboratory (a few centimeters deep).
The granite drilled during the field test is the same type of hard rock found in the basement layer of the Earth’s crust.
Quaise has plans to build a gyrotron with 10x more power.
A pilot power plant in the Western U.S. is planned for as early as 2028.
This is the first-ever hybrid drilling rig, combining conventional and millimeter wave capabilities.
Quaise plans to drill superhot geothermal wells that can generate abundant baseload power in record time. They believe there is no other energy solution capable of the same scale and speed.
“The cube sends electomagnetic energy to the drill bit to melt rock – New Atlas photoCore showing vitrified granite/basalt walls of the borehole – New Atlas photo
We reached a new milestone with our millimeter wave #drilling system: our first 10 ft hole drilled outside lab conditions
This achievement was accomplished using our compact drilling rig, now scheduled for initial field trials later this quarter targeting a depth of 100 meters pic.twitter.com/pMlhsEvSED
“Last month, we demonstrated millimeter wave drilling outside of the lab for the very first time.“
“Millimeter wave drilling is the keystone of superhot geothermal. It’s the only way to access the resource at scale while reaching economic and power parity with fossil fuels. Over the coming months, two more drilling field tests will pave the way to our first commercial developments.”
“In an age when energy policy is so often hostage to fierce partisanship, there is hope that geothermal can be the one clean energy solution that could satisfy climate change campaigners and the ‘drill baby drill’ lobby alike.”
Updates on Quaise Energy’s highly anticipated gyrotron field test and related information:
“Lab-test data suggest that the gyrotron’s beam will lose only around 50% of its power at a depth of six miles. To put that into perspective, the attenuation of a rotating drill string at 10 kilometers can be 98%,” Araque said. “You only get 2% of the mechanical power down to the bit.”
Quaise’s field test will take place on a disused oil drilling pad in the northern exurbs of Houston. Next month, a gyrotron 100 times as powerful as the one in the laboratory will be pointed at the earth and switched on.
By spring, Quaise will have erected another platform in a disused quarry near Marble Falls, a city on the Colorado River northwest of Austin.
Quaise’s ultimate ambition is that its drills can be “dropped-in” to existing oil and gas wells.
By 2026, Quaise should be positioned to launch its first commercial venture. Within that short timescale, an answer to the question of whether superdeep geothermal can be truly transformative should come into clearer focus.
Quaise’s Araque: “Our civilization uses 25 terawatts, and it doubles every 25 years. By 2050 we need 50 terawatts. By 2100 we need 200 terawatts. When you look at those numbers, you realize that diffuse and intermittent renewables don’t have the scale. The externalities are too high.”
Ultra-deep geothermal is arguably the renewable energy resource with the greatest long term potential. It is accessible everywhere, can replace thermal energy sources at existing power plants, and isn’t handicapped by the intermittency, space preemption, aesthetic, and wildlife protection challenges inherent in wind and solar development.
A new study found that rock that fractures at superhot conditions (see diagram above) can be ten times more permeable than rock that fractures at conditions closer to the Earth’s surface, and can also deform more readily.
Why is this important?
More water can pass through fractures and become supercritical (see diagram below)
The next big step for ultra-deep geothermal is demonstrating the technology to efficiently drill wells to depths of ~20 km. In that regard, we are awaiting Quaise Energy’s field test of their gyrotron drilling system.
A recent millimeter wave drilling test conducted at the Quaise laboratory, in preparation for upcoming field demonstrations
Ultradeep geothermal has enormous potential for power generation without being handicapped by the intermittency, space preemption, aesthetic, and wildlife protection challenges inherit in wind and solar projects.
Quaise Energy is an exciting company, not only because of ultradeep geothermal’s unlimited energy potential, but also because of their fascinating gyrotron technology that vaporizes hard rock and could enable drilling to depths of 20-30 km and temperatures of >1000° C.
Quaise Energy’s latest update includes some good photos of laboratory tests of their drilling technology. The first field tests of their drilling technology are supposed to be conducted later this year, but no details have been provided.
Quaise describes millimeter waves (MMWs) as follows: “… a portion of the electromagnetic spectrum between microwaves and infrared. Named for their wavelength measuring 1-10 millimeters, MMWs are everywhere yet invisible to the naked eye. The fingerprints of the Big Bang still linger as MMWs all around us in the cosmic microwave background. And if you’re reading this on a phone, chances are it was transmitted by 5G using MMWs.”
The plan is to drill through sedimentary rocks with conventional technology and use MMWs to vaporize basement rock with dielectric heat. There are many hurdles to clear, starting with the field tests, but the enormous energy potential is undeniable.