"Geothermal energy is available everywhere on massive scales," said Araque. "If you take all fossil, all nuclear, and all other forms of renewable energy combined, they're not even a millionth of a millionth of the thermal stores of energy" below the Earth's surface. "It's mind-boggling, and to get it, we only have to go down two to twelve miles. That's how close we are to infinite clean energy no matter where you are in the world."
Araque was speaking on May 21 at the first demonstration of the company's drilling technology at a full-scale oil rig owned by Nabors, one of the world's largest oil-and-gas drilling companies. Among the approximately 50 attendees, who included reporters, potential investors, and even potential Quaise customers, was William Restrepo, CFO of Nabors and a Quaise board member. Also on hand was Lauren Boyd, director of the Geothermal Technologies Office at the U.S. Department of Energy.
The mother lode of geothermal energy is some two to 12 miles beneath the Earth's surface where the rock is so hot that if water could be pumped to the area it would become supercritical, a steam-like phase that most people aren't familiar with. (Familiar phases are liquid water, ice, and the vapor that makes clouds.) Supercritical water, in turn, can carry some 5-10 times more energy than regular hot water, making it an extremely efficient energy source if it could be pumped above ground to turbines that could convert it into electricity.
Today we can't access those resources, except in places like Iceland where they are relatively close to the surface. The number one problem: we can't drill down far enough. The drills used by the oil and gas industries can't withstand the formidable temperatures and pressures that are found miles down without becoming exponentially more expensive with depth.
Quaise is working to replace the conventional drill bits that mechanically break up the rock with millimeter-wave energy (cousins to the microwaves many of us cook with). Those millimeter waves literally melt then vaporize the rock to create ever-deeper holes.
The general technique behind the Quaise drilling approach was developed at MIT over some 15 years. Scientists there showed that millimeter waves could indeed drill a hole in basalt (basalt and granite make up the majority of rock at great depth). This was promising in part because the gyrotron machine that produces the millimeter-wave energy is not new. It's been used for some 70 years in research toward nuclear fusion as an energy source.
Quaise has been developing the technique to drill deeper and deeper holes. The holes drilled at MIT were two inches in diameter by two inches deep. Outside the Quaise lab in Houston earlier this year, engineers succeeded in drilling a hole four inches in diameter and 10 feet deep (see video).
Andres Calabressi, Head of Manufacturing at Quaise, emceed the Quaise demonstration with a microphone to communicate over the steady rumble of powerful equipment. He explained that beginning in March, the company lowered columns of granite about nine inches in diameter into a conventionally drilled hole under the rig. Together those columns made a core some 80 feet long that sits inside a metal casing. The latter is outfitted with ports to monitor parameters like heat and pressure, data that allow the team to test recipes for optimal drilling.
The Quaise engineers then integrated the millimeter-wave technology with the rig. In the May 21 demo, they shot millimeter waves into the granite column, deepening a hole four inches in diameter that they'd already drilled to ten feet. (The next week, the team successfully drilled to 30 feet for the first time; the next goal on this phase of the work is 40 feet.)
During the demonstration, Calabressi was flanked by three large flat screens showing different dimensions of the work. One tracked key parameters like rock temperature, while another showed a video close-up of the millimeter waves melting rock. (The latter was taken previously in the Quaise lab since those interactions were not visible at the Nabors rig.)
Araque noted that the demo was "full scale in size, but not in power." The gyrotron involved produced 100 kilowatts of power. "That's a tenth of the power that will be commercially relevant, and is roughly equivalent to the power of the car you drove to this demonstration."
Next month, Quaise expects the delivery of a much larger gyrotron capable of producing one megawatt of power. "That is commercially relevant. We aim to get it to the field over the next two years," Araque said.
In the meantime, the company is preparing for another demonstration planned for July in Marble Falls, Texas. There, the team aims to drill multiple holes 130 meters (about 425 feet) deep into an actual granite outcrop for the first time. Henry Phan is Vice President of Engineering at Quaise. He explained that the Marble Falls rig will be smaller, "allowing us to be more nimble in terms of moving from one hole to another."
Cladouhos said that Quaise is working with vendors and universities "to push them to consider higher and higher temperatures." For example, last year a team at the Ecole Polytechnique Federal de Lausanne reported new insights into what happens when superhot, superdeep rock is exposed to water that can eventually transfer the rocks' heat to the surface. The work, supported in part by Quaise, was published in the journal Nature Communications. It confirmed earlier modeling work also supported by Quaise.
In addition, Cladouhos noted that Quaise has an in-house engineer who has been working on the design of superhot geothermal power plants. Earlier this year Senior Mechanical Engineer Daniel Dichter reported insights to that end in two papers.
Although still a ways off, Tier III sites, which will involve drilling as much as 12 miles down, "hold the key to making superhot geothermal a truly global energy source," according to this Quaise video. "Tier III sites could provide power to more than 90% of humanity."
For example, several were involved in the invention and development of Manara, a production and reservoir management solution developed at Schlumberger to substantially increase the recovery of oil from complex production systems. And among them, Quaise team members hold several patents.
"So I'm confident that together we can make this work," Araque concludes.
Related Links
Quaise Energy
Powering The World in the 21st Century at Energy-Daily.com
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