MIT spinout tapping into the million-year-old power source beneath our feet

What if we could retrofit virtually every coal and gas-fired power plant in the world to use a carbon-free energy source deep beneath our feet – geothermal energy.

Quaise Energy, a[{” attribute=””>MIT spinout, is working to create geothermal wells made from the deepest holes in the world.

There’s an abandoned coal power plant in upstate New York that most people consider a worthless relic. MIT’s Paul Woskov, on the other hand, has a different perspective.

Woskov, a research engineer in MIT’s Plasma Science and Fusion Center, points out that the plant’s power turbine is still intact and the transmission lines still run to the grid. Using an approach he’s been developing for the last 14 years, he’s hoping it will be back online within the decade, completely carbon-free.

Indeed, Quaise Energy, the company commercializing Woskov’s research, believes if it can retrofit one power plant, the same process will work on nearly every coal and gas power plant in the world.

Tapping into the energy source deep below our feet is how Quaise is hoping to accomplish those lofty goals. The company ambitious plans call for vaporizing enough rock to create the world’s deepest holes and harvesting geothermal energy at a scale that could satisfy human energy consumption for millions of years. Although they haven’t yet solved all the related engineering challenges, Quaise’s founders have set an aggresive timeline to begin harvesting energy from a pilot well by 2026.

If the plan were based on new and unproven technology, it would be easier to dismiss as unrealistic. However, Quaise’s drilling systems center around a microwave-emitting device called a gyrotron that has been used in research and manufacturing for decades.

Quaise Energy Deep Geothermal Wells

Quaise Energy wants to repurpose coal and gas plants into deep geothermal wells by using X-rays to melt rock. Credit: Collage by MIT News with images courtesy of Quaise Energy

“This will happen quickly once we solve the immediate engineering problems of transmitting a clean beam and having it operate at a high energy density without breakdown,” explains Woskov, who is not formally affiliated with Quaise but serves as an advisor. “It’ll go fast because the underlying technology, gyrotrons, are commercially available. You could place an order with a company and have a system delivered right now — granted, these beam sources have never been used 24/7, but they are engineered to be operational for long time periods. In five or six years, I think we’ll have a plant running if we solve these engineering 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, however, after the MIT Energy Initiative (MITEI) published a request for proposals on new geothermal drilling technologies, that Woskov thought of using gyrotrons for a new application.

“[Gyrotrons] haven’t been well publicized in the general scientific community, but those of us in fusion research have come to realize that these are very powerful beam sources – like lasers, but in a range of different frequencies,” says Woskov. “I thought, why not direct these high power beams, instead of merging[{” attribute=””>plasma, down into rock and vaporize the hole?”

As power from other renewable energy sources has exploded in recent decades, geothermal energy has plateaued, mainly because geothermal plants only exist in places where natural conditions allow for energy extraction at relatively shallow depths of up to 400 feet beneath the Earth’s surface. At a certain point, conventional drilling becomes impractical because deeper crust is both hotter and harder, which wears down mechanical drill bits.

Paul Woskov Displaying Samples

Paul Woskov displaying samples in his lab in 2016. Credit: Paul Rivenberg

Woskov’s idea to use gyrotron beams to vaporize rock sent him on a research journey that has never really stopped. With some funding from MITEI, he began running tests, quickly filling his office with small rock formations he’d blasted with millimeter waves from a small gyrotron in MIT’s Plasma Science and Fusion Center.

Around 2018, Woskov’s rocks got the attention of Carlos Araque ’01, SM ’02, who had spent his career in the oil and gas industry and was the technical director of MIT’s investment fund The Engine at the time.

That year, Araque and Matt Houde, who’d been working with geothermal company AltaRock Energy, founded Quaise. Quaise was soon given a grant by 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. That is expected to be accomplished by the end of this year. After that, the team will vaporize a hole 10 times the depth of the previous one — what Houde calls a 100-to-1 hole.

“That’s something [the DOE] is particularly interested, as they want to address the challenges of material removal over these longer lengths – in other words, can we show that we completely eliminate rock fumes? Houde explains. “We believe the 100-to-1 test also gives us the confidence to go out and mobilize a prototype gyrotron drill into the field for initial field demonstrations.”

Testing on the 100-to-1 hole is expected to be completed within the next year. Quaise also hopes to start vaping rock in field trials late next year. The short timeline reflects the progress Woskov has already made in his lab.

Although more engineering research is needed, the team expects to be able to drill and operate these geothermal wells safely. “We believe, through Paul’s work at MIT over the past decade, that most, if not all, of the fundamental questions in physics have been answered and resolved,” Houde says. “These are really engineering challenges that we have to meet, which doesn’t mean they’re easy to solve, but we’re not working against the laws of physics, to which there are no answers. It’s more about overcoming some of the more technical and cost considerations to make it work at scale. »

The company plans to begin harvesting energy from pilot geothermal wells that reach rock temperatures of up to 500°C (932°F) by 2026. From there, the team hopes start reallocating coal and natural gas plants using its system.

“We believe that if we can dig down to 20 kilometers, we can access these extremely hot temperatures in over 90% of places around the world,” Houde said.

Quaise’s work with the DOE addresses what he sees as the biggest remaining questions about drilling holes of unprecedented depth and pressure, such as material removal and determining the best casing for keep the hole stable and open. For this final well stability issue, Houde believes additional computer modeling is needed and expects to complete this modeling by the end of 2024.

By drilling the 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 that is very close to, if not better than, the temperature at which today’s coal and gas-fired power plants operate,” says Houde. “So we can go into existing power plants and say, ‘We can replace 95% to 100% of your coal consumption by developing a geothermal field and producing steam from the Earth at the same temperature as you burn coal to run your turbine, directly replacing carbon emissions.

Transforming the world’s energy systems in such a short time is something the Founders consider essential to help avoid the most catastrophic global warming scenarios.

“There have been huge gains in renewable energy over the past decade, but the big picture today is that we are not moving fast enough to meet the milestones we need to limit the worst impacts. of climate change,” says Houde. “[Deep geothermal] is an energy resource that can scale anywhere and has the ability to tap into a large energy industry workforce to easily retrain their skills for a completely carbon-free energy source.

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