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Drilling 12 Miles Down to Tap Geothermal Energy

Quaise Energy, a Boston company, is using tech from nuclear fusion experiments to reach new depths.

Most geothermal power today comes from natural geysers or drilling operations that plunge a few miles down to harness heat from buried rock. 

Quaise Energy, a startup based in Boston, is taking a third approach: digging deeper—and using more heat—than any company has before. To do so, it’s refashioning a millimeter-wave drilling technique from nuclear fusion experiments.

Carlos Araque, Quaise’s chief executive officer, likens it to “a big cousin of the microwave in your kitchen”—only with 1,000 times more power. “It’s a fairly mature technology,” he says. “We just use it for this purpose.” 

Geothermal is an also-ran of renewables. It only accounts for 0.2% of the world’s power supply, according to BloombergNEF, a clean energy research group. It’s a risky business, but one with the capacity produce terrific amount of energy with limited emissions. But geothermal operators often struggle to find fruitful places to dig and few have tried digging much below a few miles down.

Araque, a former engineer for oil services company Schlumberger, says that’s because it hasn’t made financial sense. For years, oil and natural gas has been cheaper to produce and easier to sell. Once a drill gets a few miles down into the Earth’s crust, the high temperature and pressure start to damage the equipment.

“It’s very simple,” Araque says. “It’s risk-reward. It’s the economics.”

Those economics are changing as ESG standards and new legislation reward buying cleaner energy. Quaise plans to start testing its drills in fields near Albuquerque, New Mexico, and Bend, Oregon in 2024.

The company’s drill—it is building three prototypes in laboratories—is about 100 feet tall and looks like conventional equipment used in the oil and gas industry. Except built into the center of the drill is a gyrotron, an electrical vacuum designed to heat plasma in thermonuclear fusion machines. It’s designed to go as much as 12 miles deep and access steam as hot as 500C. 

Right now, experts consider 150C an extraordinarily high temperature for such operations, says Maria Richards, who runs the Geothermal Laboratory at Southern Methodist University.

She applauds Quaise’s ambition, but is skeptical that it can dig as deeply as advertised in its designated areas, where the terrain is volcanic and tough. “All of a sudden, the equipment fails,” Richards says. “It’s not an easy area to drill.”

Quaise has an aggressive timeline. By 2026, the startup hopes to have the “first super-hot” system producing 100 megawatts of power—Araque estimates this will take less than 10 geothermal wells. By 2028, Quaise wants to retrofit an entire fossil fuel power plant with geothermal. 

Araque says Quaise has held talks with power plant owners and other energy providers, although he isn’t ready to share names. The company has raised $75 million since spinning out of MIT, where the initial concept for the drilling tech was formed. To fully retrofit a first power plant, Araque estimates that the overall process will cost $1 billion. 

He says he isn’t worried about capital. Quaise counts several individual investors who, according to Araque, know that a clean energy economy requires taking some technical risks. “We’re not doing this because it’s cool,” he says. “We do this because there are very few other options.”