A piece of Soviet-era physics equipment may hold the key to global geothermal energy.
MIT research engineer Paul Woskov spent 14 years developing a technique to use gyrotrons, normally used to heat plasma, to drill geothermal wells. Gyrotrons emit microwaves and have been used in physics research for decades; The repurposing of Woskov gives the venerable devices a new use case.
According to people at the International Thermonuclear Experimental Reactor project, first gyrotron was developed in 1964 at the Institute of Applied Physics (the Russian Academy of Sciences).
Despite their age, gyrotrons are not well publicized in the scientific community, Woskov said. “Those of us in fusion research understood that they were very powerful beam sources – like lasers, but in a different frequency range. I thought, why not direct these powerful beams down into rock instead of fusion plasma and vaporize the hole,” he said. Woskov.
The commercialization of Woskov’s gyrotron drill comes from Quaise Energy, a company out of MIT. Woskov does not work for the company, but acts as a consultant.
Paul Woskov with his gyrotron core samples
Other forms of renewable energy have risen in popularity beyond geothermal, MIT said Today. The reason has nothing to do with the effectiveness of geothermal energy, rather its impracticality and enormous cost.
“Geothermal plants only exist in places where natural conditions allow for energy extraction at relatively shallow depths up to 400 feet (c 120 m),” MIT said.
Drill much deeper, and the heat of the Earth’s crust wears out drills too quickly to be practical.
The ultimate goal of Quaise is to convert coal and natural gas plants into geothermal generators, but there are two technical issues that need to be solved before they get there: the gyrotron beam must be clean and must continuously produce a high energy density without breaking down.
Matt Houde, who left the geothermal company AltaRock Energy to found Quaise with MIT administrator Carlos Araque, said that all of the fundamental physics problems have been solved by Woskov, leaving “only” those technical problems. “It’s more a matter of overcoming some of the more technical and cost considerations to make this work at scale,” Houde said.
By the end of 2022, Quaise aims to have vaporized a hole 10 times as deep as Woskov’s lab experiments, and by 2023 it plans to vaporize a second hole 10 times deeper than the first. Houde said the planned depth of the second hole will give the company enough confidence to begin field experiments next year as well. By 2026, Quaise aims to have an active pilot well that will reach temperatures of 500°C (932°F).
“If we can drill up to 20 kilometers, we can access these super-hot temperatures in more than 90 percent of locations around the world,” Houde said.