MIT spinout Quaise Energy is working to create geothermal wells made from the world’s deepest holes.
MIT News Office
In upstate New York, there is an abandoned coal-fired power plant that most people consider a useless relic. But Paul Woskov of MIT sees things differently.
Woskov, a research engineer at MIT’s Plasma Science and Fusion Center, notes that the plant’s power turbine is still intact and transmission lines still run to the grid. Using the approach he’s been working on for the past 14 years, he hopes to be back online, completely carbon-free, within ten years.
In fact, Quaise Energy, the company commercializing Woskov’s work, believes that if it can retrofit one power plant, the same process will work for virtually every coal and gas-fired power plant in the world.
Quaise hopes to achieve these lofty goals by tapping the energy source beneath our feet. The company plans to vaporize enough rock to create the world’s deepest holes and harvest geothermal energy on a scale that could meet human energy needs for millions of years. They haven’t yet solved all the engineering challenges involved, but Quaise’s founders have set an ambitious timeline to begin harvesting energy from the pilot well by 2026.
It would be easier to dismiss the plan as unrealistic if it was based on new and unproven technology. But Quaise’s drilling systems center around a microwave device called a gyrotron that has been used in research and production for decades.
“This will happen quickly once we solve the immediate technical problems of transmitting the pure beam and operating it at high energy density without failure,” explains Woskov, who is not formally affiliated with Quaise but serves as an advisor. “It will go quickly because the basic technology, gyrotrons, is commercially available. You can place an order with the company and have the system delivered to you now – of course, these beam sources have never been used 24/7, but they are designed to be operational for a long time. In five or six years, I think we will have a plant in operation if we solve these technical problems. I’m very optimistic.”
Woskov and many other researchers have been using gyrotrons to heat material in nuclear fusion experiments for decades. It wasn’t until 2008, after MIT’s Energy Initiative (MITEI) published a request for proposals for new geothermal drilling technologies, that Woskov thought of using gyrotrons for a new application.
“[Gyrotrons] they weren’t publicized enough in the general scientific community, but those of us in fusion research understood that these are very powerful beam sources – like lasers, but in a different frequency range,” says Woskov. “I thought, why not direct these high-powered beams down into the rock instead of into the fusion plasma and vaporize the hole?”
As energy from other renewable energy sources has exploded in recent decades, geothermal energy has stagnated, largely because geothermal power plants exist only in places where natural conditions allow energy to be extracted at relatively shallow depths of up to 400 feet below the Earth’s surface. At some point, conventional drilling becomes impractical because the deeper crust is hotter and harder, which wears out mechanical drills.
Woskov’s idea to use gyrotron beams to vaporize rock sent him on a research journey that never really stopped. With some funding from MITEI, he began conducting tests and quickly filled his office with small rock formations that he blasted with millimeter waves from a small gyrotron at MIT’s Plasma Science and Fusion Center.
Around 2018, Woskov’s rocks caught the attention of Carlos Araque ’01, SM ’02, who had spent his career in the oil and gas industry and at the time was the technical director of MIT’s investment fund The Engine.
That year, Araque and Matt Houde, who worked with geothermal company AltaRock Energy, founded Quaise. Quaise soon received a grant from the Department of Energy to expand Woskov’s experiments with a larger gyrotron.
With the larger machine, the team hopes to vaporize a hole 10 times the depth of Woskov’s lab experiments. It is expected to be done by the end of this year. Then the team vaporizes the hole 10 times the depth of the previous one—what Houde calls a 100-to-1 hole.
“It’s something [the DOE] is of particular interest because they want to address the challenges of removing material at these longer lengths—in other words, can we show that we’re fully leaching rock vapors?” Houde explains. “We believe the 100 to 1 test also gives us the confidence to go out and mobilize the prototype gyrotron drilling rig in the field for the first field demonstrations.”
Tests on the 100 to 1 pit are expected to be completed sometime next year. Quaise also hopes to begin vaporizing rock in field tests late next year. The short timeline reflects the progress Woskov has already made in his lab.
Although more engineering research is needed, the team eventually expects to be able to safely drill and operate these geothermal wells. “Thanks to Paul’s work at MIT over the last decade, we believe that most, if not all, fundamental questions in physics have been answered and resolved,” says Houde. “We have to answer really technical challenges, which doesn’t mean they can be easily solved, but we’re not working against the laws of physics that don’t have an answer. It’s more about overcoming some of the more technical and cost aspects to make it work at scale.”
The company plans to start extracting energy from pilot geothermal wells, which reach rock temperatures of up to 500°C by 2026. Since then, the team hopes to begin converting coal and natural gas power plants using their system.
“We believe that if we can drill down to 20 kilometers, we will have access to these extremely high temperatures in more than 90 percent of places around the world,” says Houde.
Quais’ work with DOE addresses what he sees as the biggest remaining questions about drilling holes of unprecedented depth and pressure, such as removing material and determining the best casing to keep the hole stable and open. For the second well stability issue, Houde believes more computer modeling is needed and expects to complete that modeling by the end of 2024.
By drilling holes in existing power plants, Quaise will be able to move faster than if it had to get permits to build new plants and transmission lines. And by making their millimeter wave drilling rig compatible with the existing global rig fleet, it will also allow the company to tap into the global oil and gas industry workforce.
“At these high temperatures [we’re accessing], we are producing steam very close to, if not exceeding, the temperature at which today’s coal and gas-fired power plants operate,” says Houde. “So we can go to existing power plants and say, ‘We can replace 95 to 100 percent of your coal consumption by developing a geothermal field and generating steam from the earth at the same temperature that you burn coal to run your turbine.’ directly replacing carbon emissions.”
Transforming the world’s energy systems in such a short time frame is something the founders believe is essential to avoid the most catastrophic global warming scenarios.
“Over the last decade, there have been huge gains in renewable energy, but the big picture today is that we are not moving fast enough to achieve the milestones we need to limit the worst impacts of climate change,” says Houde. “[Deep geothermal] is an energy source that can scale anywhere and has the ability to tap into a large workforce in the energy industry and readily repackage their skills into a completely carbon-free energy source.”
Related: Researchers are pioneering a new look at deep rock fractures for geothermal energy
Do you appreciate CleanTechnica’s originality and reporting? Consider becoming a CleanTechnica member, supporter, technician or ambassador – or a patron on Patreon.