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MIT Spinout Tapping Into the Million-Year Energy Source Below Our Feet

Earth's Internal Stucture

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

Quaise Energy, an 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 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 science community, but those of us in fusion research understood they were very powerful beam sources — like lasers, but in a different frequency range,” Woskov says. “I thought, why not direct these high-power beams, instead of into fusion 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 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 in, because they want to address the challenges posed by material removal over those greater lengths — in other words, can we show we’re fully flushing out the rock vapors?” Houde explains. “We believe the 100-to-1 test also gives us the confidence to go out and mobilize a prototype gyrotron 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 is also hoping 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, ultimately, the team expects to be able to drill and operate these geothermal wells safely. “We believe, because of Paul’s work at MIT over the past decade, that most if not all of the core physics questions have been answered and addressed,” Houde says. “It’s really engineering challenges we have to answer, which doesn’t mean they’re easy to solve, but we’re not working against the laws of physics, to which there is no answer. It’s more a matter of overcoming some of the more technical and cost considerations to making this work at a large 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 to begin repurposing coal and natural gas plants using its system.

“We believe, if we can drill down to 20 kilometers, we can access these super-hot temperatures in greater than 90 percent of locations across the globe,” Houde says.

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

By drilling the holes at 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 equipment compatible with the existing global fleet of drilling rigs, it will also allow the company to tap into the oil and gas industry’s global workforce.

“At these high temperatures [we’re accessing], we’re producing steam very close to, if not exceeding, the temperature that today’s coal and gas-fired power plants operate at,” Houde says. “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 producing steam from the Earth, at the same temperature you’re burning coal to run your turbine, directly replacing carbon emissions.”

Transforming the world’s energy systems in such a short timeframe is something the founders see as critical to help avoid the most catastrophic global warming scenarios.

“There have been tremendous gains in renewables over the last decade, but the big picture today is we’re not going nearly fast enough to hit the milestones we need for limiting the worst impacts of climate change,” Houde says. “[Deep geothermal] is a power resource that can scale anywhere and has the ability to tap into a large workforce in the energy industry to readily repackage their skills for a totally carbon-free energy source.”

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  • The description of the second figure is incorrect. Gyrotron drilling technology does NOT use X-rays! (Only Superman can do that.) It uses microwaves, or more properly, millimeter waves. However, the process is very energy intensive. A large amount of energy will be required just to drill the hole(s).

    A headache for all geothermal energy systems is that the water used is contaminated with dissolved minerals, which precipitate out when the water cools or evaporates, plugging pipes and heat exchangers. Water is close to being a universal solvent, meaning it can dissolve anything under the right circumstances. Once they drill their hole(s) and inject water, it will start dissolving the walls of the holes, which will then start plugging up their plumbing system. It will also start cooling the surrounding rocks, resulting in reduced thermal efficiency. Additionally, there should be concern about eventually dissolving the impermeable silicate-glass walls of the drill holes, and possibly leaking to places the steam or hydrothermal water is not wanted. In any event, it doesn't look like they have done an analysis of the expected longevity of the geothermal wells, and therefore, can't estimate the net energy gain over the energy cost of drilling the wells.

    Once again, technologists enamored with their pet technology appear not to have looked at the Big Picture.

  • Sounds great! My layperson's long-term concern is the possibly this tech at scale could cause Earth's interior to cool enough to affect the molten iron dynamo that generates our magnetic field

  • Clyde: "Quaise’s work with the DOE is addressing what it sees as the biggest remaining questions about drilling holes of unprecedented depth and pressure, such as material removal and determining the best casing to keep the hole stable and open. "

    Most of your critique seems to center on them pumping water into a raw drilled hole. Note they mention the oil and gas industry and casing type for the drilled holes. Obviously this hasn't been done(successfully, or with this kind of technique) before and as they admit the engineering isn't figured out yet. Without knowing the engineering or materials involved and having no real world case studies(how many 20 km deep holes have been drilled...hmmm?) its impossible to do a cost analysis.

    They may never drill as deep as they hope and/or other problems may occur that prevent this from being successful. However, if it works as they hope it could be one of the biggest advances for mankind in our lifetimes. Don't be so quick to label it a pipe dream... heh.

    • Conventional drill holes are cut with diamond-tipped cutting heads, leaving rock that is porous. They have to be lined with steel casing. This new technique is melting the rock, essentially sealing it with glass. However, it may well still need to be lined. We'll find out.

      Inasmuch as they are doing their drilling at an abandoned power site, this isn't just an experimental drilling program. The implication is that they intend to put water down the bore holes. All deep wells to date have ended up being responsible for small earthquakes, which the local residents haven't been happy with. I predict that the situation will be worse here because as they cool the surrounding rocks, they will contract, causing a different environment than injecting high-pressure liquids.

      https://www.westword.com/news/denver-earthquakes-40-years-ago-were-caused-by-uncle-sam-not-mother-nature-5833488

  • Gods...y'know, millions of volts at hundreds of thousands of amps enter and leave the Earth every second, and what do people want to do?

    Burn stuff. Dig junk up. Spin blades in the air and water. Then, after all the fun, only then convey it to the electricity that is *already in the air*.

    100 volts-per-meter, that's the Earth's Fairweather field. How much power could be shorted to use at a ground station with a balloon and some highly conductive cabling? Multiple balloon rigs?

    Cheap, easy, ready to use power right there in the sky, being constantly ignored because research grants, right?

    Greed and capitalism will kill us as a species yet. Earth will be better off without us, too.

    • Yes, there is a substantial electric gradient between the Earth and the ionosphere. It increases substantially when a thunder storm passes overhead. However, because air is a good insulator (except when it is broken down into ions by a lightning discharge) only microamperes are capable of being drawn. Even lightning bolts don't provide usable power because they are of such short duration.

  • "The Rocky Mountain Arsenal deep injection well was constructed in 1961, and was drilled to a depth of 12,045 feet. The well was cased and sealed to a depth of 11,975 feet, with the remaining 70 feet left as an open hole for the injection of Basin F liquids. For testing purposes, the well was injected with approximately 568,000 gallons of city water prior to injecting any waste. However, when the Basin F liquids were actually introduced, the process required more time than anticipated to complete because of the impermeability of the rock. The end result was approximately 165 million gallons of Basin F liquid waste being injected into the well during the period from 1962 through 1966."

    That is drilling a hole and injecting fluid into the rock. They were basically drilling a super deep hole and fracking mystery waste water into it. Hydraulic fracturing does, or can cause quakes, that is well documented. This has been a criticism of the oil and gas industry's hydraulic fracturing technique.

    Drilling cased holes(presumably joined at the bottom) and pumping water into one end and getting steam out of the other end is an entirely different process. This isn't fracking, but the extreme depth creates unknowns. I don't think they mentioned it in this particular article, but the deepest hole ever drilled is about 7km. These guys are talking about drilling to several times the depth that holes have been drilled at before. There could be unforeseen consequences with these new depths, but their intent is not fracking.

  • Why is geothermal not being mentioned in the news as much as solar and wind is? I just learned that Northern California has a few small G.T. plants. And with Plasma drill bits we may be able to get deeper especially when drilling for oil is already part of our fossil fuel 'life'. Seems it would be easier to train drilling companies to drill deeper with high tech bits rather than retrain them into solar and wind? Let's find a way to get Geo-thermal out and into the public mindset!

By
Zach Winn, Massachusetts Institute of Technology
Tags: EnergyMIT

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