Fusion Technology to Revolutionize Geothermal Power
Haley Zaremba

The Earth’s core produces so much heat that if we could tap just one tenth of one percent of it, the world’s energy needs would be satisfied for the next 20 million years. And that infinite source of power would yield zero greenhouse gases in the process. But while geothermal energy thrives today in places like Iceland, where heat from the Earth’s core naturally comes up to the surface of the Earth’s crust, for the rest of the world it remains out of reach. 

At present, geothermal accounts for a mere 0.5% of renewable energy on a global scale. And growing that share will require some serious technological breakthroughs. “To grow as a national solution, geothermal must overcome significant technical and non-technical barriers in order to reduce cost and risk,” says the introduction to a 2019 U.S. Department of Energy (DOE) report — GeoVision: Harnessing the Heat Beneath Our Feet. “The subsurface exploration required for geothermal energy is foremost among these barriers, given the expense, complexity, and risk of such activities.” 

But scientists are hard at work trying to figure out a way to tap into that heat from anywhere on the planet. All it will require is digging the deepest hole in human history. The Earth's crust varies from about 3 to 47 miles in thickness, and most of those thin bits are way out in the deepest parts of our oceans. So far, the deepest humans have ever dug was a vertical depth of just 12,289 meters (40,318 feet or just over 7.6359848 miles) way back in 1989. And in that project, the Russian Kola Superdeep Borehole, was deemed a failure after it was unable to reach its end goal of the Earth’s mantle – but it managed to tap into temperatures measuring 180 °C (356 °F) using traditional drilling technologies alone.

“Where conditions become too difficult for physical drill bits to operate, researchers have been testing the capabilities of directed energy beams to heat, melt, fracture and even vaporize basement rock in a process called spallation, before the drill head even touches it,” New Atlas recently reported.

Now, researchers are investigating other, more reliable ways to reach depths as great and greater than the Kola borehole, in order to make geothermal plants feasible for installation anywhere on the planet. Some projects have looked into borrowing technologies from the fracking industry to accomplish this goal. But so far this approach has not been fruitful, either as these technologies remain cost prohibitive. “For now, federal analysis shows this type of geothermal costs around $181 per megawatt hour, while utility-scale solar costs just $25,” NPR reported in 2023. However, some geothermal experts project that those costs will decrease by about a third over the next decade. 

So now science has turned to poaching technology from an entirely different sector – nuclear fusion research. Gyrotrons are currently used in nuclear fusion experiments to super-heat and maintain plasma. But Quaise Energy, and MIT offshoot based in Cambridge, Mass., argues that they can also be used to drill deeper and more efficiently than ever before, by melting rock with energy beams. Quaise Energy has already raised $95 million from investors (including Mitsubishi) to apply gyrotrons to geothermal energy extractions. 

The MIT team’s experimenting and mathematical models suggest that “a millimeter-wave source targeted through a roughly 20 centimeter waveguide could blast a basketball-size hole into rock at a rate of 20 meters per hour,” according to IEEE Spectrum. “At that rate, 25-and-a-half days of continuous drilling would create the world’s deepest hole.” Move over, Kola Superdeep Borehole. 

This could have enormous ramifications for the future of energy as we know it, and a silver bullet for climate change to boot. “Barring too many further surprises, [gyrotron technology] should [...] significantly change the equation for ultra-deep drilling, making it possible and profitable to get deep enough into the crust to unlock some of the Earth's immense geothermal energy potential,” New Atlas reports. 

By Haley Zaremba for Oilprice.com

  

 

 

Haley Zaremba is a writer and journalist based in Mexico City. She has extensive experience writing and editing environmental features, travel pieces, local news in the Bay Area, and music/culture reviews.

 

 

 

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