MIT spinout Quaise Energy is working to create geothermal wells made from the deepest holes in the world.
MIT News Office
There is an abandoned coal-fired power plant in upstate New York that most people consider a useless relic. But Paul Woskov of MIT sees things differently.
Woskov, a research engineer at MIT’s Center for Plasma and Fusion Science, 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 on the grid, completely carbon-free, within a decade.
In fact, Quaise Energy, the company commercializing Wosk’s work, believes that if it can reengineer one power plant, the same process will work at nearly every coal and gas-fired power plant in the world.
Quaise hopes to achieve those lofty goals by tapping into 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 consumption for millions of years. They still haven’t solved all the associated engineering challenges, but Quaise’s founders have set an ambitious timeline to begin harvesting energy from pilot wells 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 on a microwave-emitting device called a gyrotron that has been used in research and production for decades.
“This will happen quickly once we solve the immediate engineering problems of transmitting a clean beam and operating it at high energy density without failure,” explains Woskov, who is not formally affiliated with Quaise but serves as an adviser. “It will go fast because the basic technology, gyrotrons, are commercially available. You can order the company and have the system delivered immediately – of course, these beam sources have never been used 24/7, but they are designed to be operational for a long period of time. In five or six years, I think we will have a power plant operating if we solve these engineering problems. I am very optimistic.”
Woskov and many other researchers have been using gyrotrons for decades to heat materials in nuclear fusion experiments. However, it wasn’t until 2008, after the MIT Energy Initiative (MITEI) issued a request for proposals on new geothermal drilling technologies, that Woskov considered using gyrotrons for a new application.
“[Gyrotrons] they were not well publicized in the general scientific community, but those of us in fusion research realized that these were very powerful beam sources – like lasers, but in a different frequency range,” says Woskov. “I thought, why not direct these high-powered beams, instead of into fusion plasma, down into the rock and vaporize the hole?”
As energy from other renewable energy sources has exploded over the past few decades, geothermal energy has stagnated, largely because geothermal 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 a certain point, conventional drilling becomes impractical because the deeper crust is hotter and harder, which wears out the mechanical drill bit.
Woskov’s idea to use gyrotron beams to vaporize rocks sent him on a research journey that never stopped. With some money from MITEI, he began conducting tests, quickly filling his office with small rock formations that he blasted with millimeter waves from a small gyrotron at MIT’s Center for Plasma Fusion and Science.
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 CTO of MIT’s investment fund The Engine.
That year, Araque and Matt Houde, who worked with the geothermal company AltaRock Energy, founded Quaise. Quaise soon received a grant from the Department of Energy to scale up Woskov’s experiments using 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 that this will be achieved by the end of this year. After that, the team will vaporize a hole 10 times the size of the previous one – what Houde calls a 100-to-1 hole.
“That’s something [the DOE] is particularly interested, because they want to solve the challenges posed by removing material at these longer lengths – in other words, can we show that we completely wash away rock vapors?” Houde explains. “We believe the 100 to 1 test also gives us the confidence to go out and mobilize a prototype gyrotronic drilling rig in the field for the first field demonstrations.”
Tests on the 100 to 1 hole are expected to be completed sometime next year. Quaise also hopes to begin vaporizing rock in field tests late next year. The short time frame reflects the progress Woskov has already made in his lab.
Although more engineering research is needed, the team ultimately expects to be able to safely drill and operate these geothermal wells. “We believe, because of Paul’s work at MIT over the past decade, that most, if not all, fundamental questions in physics have been answered,” says Houde. “These are really engineering challenges that we have to answer, which does not mean that they are easy to solve, but we are not working against the laws of physics, which have no answers. It’s more a matter of overcoming some of the technical and cost considerations to make this a big deal.”
The company plans to begin harvesting energy from pilot geothermal wells that reach rock temperatures of up to 500°C by 2026. From there, the team hopes to begin converting coal and natural gas plants using their system.
“We believe if we can drill down to 20 kilometers, we can access these super-hot temperatures in more than 90 percent of locations around the world,” says Houde.
Quaise’s 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 final well stability issue, Houde believes additional computer modeling is needed and expects that modeling to be completed by the end of 2024.
By drilling holes in existing power plants, Quaise will be able to move faster than if it had to obtain permits to build new power plants and transmission lines. And by making their millimeter wave drilling equipment compatible with the existing global fleet of drilling rigs, it will also allow the company to tap into the global oil and gas industry workforce.
“At these high temperatures [we’re accessing], we produce 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 use by developing a geothermal field and generating steam from the Earth, at the same temperature 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 consider crucial to avoiding the most catastrophic global warming scenarios.
“There have been huge improvements in renewables over the past decade, but the big picture today is that we are not going nearly fast enough to reach the milestones we need to limit the worst impacts of climate change,” says Houde. “[Deep geothermal] is an energy source that can be scaled anywhere and has the ability to engage a large workforce in the energy industry to easily repackage their skills for a completely carbon-free energy source.”
Related: Researchers pioneer new look at deep rock fractures for geothermal energy
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