- Geothermal energy holds great promise for the United States as it is directly underfoot and can be used for electric generation, space heating and energy storage.
- Hydraulic fracturing and horizontal drilling pioneered in the oil and gas industry are being employed to assist in unlocking geothermal energy’s potential.
- Unlike wind and solar power favored by the Biden Administration, geothermal energy can be produced without disturbing large areas of land.
- Geothermal is receiving less than 1 percent of the federal funding that “clean” hydrogen is receiving in the recent infrastructure bill.
The United States is looking to unlock its geothermal resources by using techniques from the oil and gas fracking boom. A drilling rig transplanted from the oil fields of North Dakota is now drilling for heat in Utah using hydraulic fracturing and horizontal drilling technologies. Geothermal energy, a source of renewable power, is found in the Earth’s hot interior. Unlike wind and solar power, geothermal does not use much land and it also does not produce carbon emissions. Traditional geothermal plants work by tapping natural hot water reservoirs underground to power turbines that can generate electricity 24 hours a day, but the technology is very expensive. Because few geothermal sites have the right conditions, the resource produces only 0.4 percent of America’s electricity currently. By using advanced drilling techniques developed by the oil and gas industry, some believe it is possible to tap that larger store of heat in the ground and create geothermal energy almost anywhere. The U.S. Energy Department estimates there is enough energy in underground rocks to power the entire country five times over and is working to help develop technologies to harvest that heat.
One company, Fervo, is using fracking techniques, similar to those used for oil and gas, to crack open dry, hot rock and inject water into the fractures, creating geothermal reservoirs. Another company, Eavor, a Canadian start-up, is building large underground radiators with drilling methods pioneered in Alberta’s oil sands. Others possibilities being considered use plasma or energy waves to drill even deeper and tap “superhot” temperatures that could power coal-fired power plants with steam instead of coal.
Obstacles to Expansion
Investors are wary of the cost and risks of new geothermal projects. Some worry about water use or earthquakes from drilling as earthquakes were a problem that plagued geothermal projects in South korea and Switzerland. Underground geology is complex, and it is tricky to create fractures that maintain heat and do not lose too much water over time. Permitting, as in other projects, is difficult and time-delaying. The best geothermal resources are located on federal lands where regulatory reviews take years. Geothermal also gets less federal support than other technologies. The recent infrastructure bill provided $9.5 billion for “clean” hydrogen, but just $84 million for advanced geothermal, an amount less than 1 percent of the former.
Geothermal Fracking
Traditional geothermal production relies on hot, naturally porous rocks that allow groundwater to percolate and heat up enough to create steam for generating electricity. Bus such conditions are rare. Much of the underground hot rock is hard granite, and water cannot flow easily, making the way for fracking to be tried. Innovations like horizontal drilling and magnetic sensing pushed oil and gas production to record highs due to steep cost declines in the drilling process. These techniques can be adapted for geothermal, where drilling can make up half the cost of projects.
Two teams are trying to tap the hot granite using fracking technologies. One is Utah FORGE, a $220 million research effort funded by the Energy Department, and the other, mentioned above is Fervo, a Houston-based start-up. Using similar methods, they drill two wells shaped like giant L’s, extending thousands of feet into hot granite and then curving and extending thousands of feet horizontally. Hydraulic fracturing is then used to create a series of cracks between the two wells. Finally, water is injected into one well, where it mitigates through cracks, heats up over 300 degrees Fahrenheit and comes out the other well.
In July FORGE announced it had successfully sent water between two wells. Two weeks later, Fervo announced a breakthrough at a 30-day test in Nevada that produced enough heat for electricity. Fervo is now drilling wells for its first 400-megawatt commercial power plant in Utah, next to the FORGE sire. Fervo’s drilling is conducted by Helmerich & Payne, a major oil and gas contractor that developed a high-tech rig with software and sensor that allow operators to steer drill bits underground. Sixty percent of Fervo’s employees came from the oil and gas industry, using their highly developed skills to benefit the operation.
The Energy Department estimates that geothermal could supply 12 percent of America’s electricity by 2050 if technology improves. But, it still needs to make enhanced geothermal affordable. Costs need to plummet to $45 per megawatt-hour for widespread employment. Drilling deeper and hotter can make projects more cost-effective, since more heat means more energy. But existing oil and gas equipment was not designed for temperatures above 350 degrees, so new tools in hotter rock are being tested.
In Texas, Sage Geosystems is pursuing fracked wells that act as batteries. When there is surplus electricity on the grid, water gets pumped into the well. When energy is needed, pressure and heat in the fractures pushes water back up, delivering energy.
Other Techniques
Another technique for accessing geothermal resources is a “closed loop” system, which involves drilling sealed pipes into hot, dry rocks and then circulating fluid through the pipes, creating a giant radiator. This avoids the unpredictability of water flowing through underground rock, but requires more complicated drilling. Eavor tested a closed-loop system in Alberta and is now building its first 65-megawatt plant in Germany.
“Superhot” geothermal works by drilling six miles or more underground where temperatures exceed 750 degrees Fahrenheit. At that point, water goes supercritical and can hold five to 10 times as much energy as normal steam. If it works, “superhot” geothermal could be used anywhere. Going that deep, however, requires futuristic tools. GA Drilling, a Slovakian company, is developing plasma torches for drilling at high temperatures. Quaise, a Massachusetts-based start-up, wants to use millimeter waves – high-frequency microwaves – to pulverize rock and reach depths of up to 12 miles.
Advocates against Oil and Gas Want to Ban Fracking
Since hydraulic fracturing and horizontal drilling opened shale rock to oil and natural gas production, liberal politicians have tried to discredit the procedure to essentially ban the use of the technology. New York State, for example, has banned fracking, despite huge resources in its “southern tier” which is an extension of the Marcellus Shale deposit. It is due to hydraulic fracturing, however, that the United States achieved an oil and natural gas renaissance and the the United States could become energy independent. The procedure also enabled the United States to become the top oil and natural gas producer in the world, taking away OPEC’s monopoly power and lessening Russia’s sway in world markets.
There have been a number of studies trying to tie health issues to fracking to ban its use for oil and gas production. The most recent study on health effects related to fracking was commissioned by former Pennsylvania Governor Tome Wolf, funded by $2.5 million from the Pennsylvania Department of Health. The study did not show a causal relationship between certain childhood health problems and they hydraulic fracturing process but did establish a very small correlation between childhood lymphoma and some fracking procedures. The study, however, did not review other possible reasons for the correlations.
Conclusion
Geothermal drillers are using hydraulic fracturing and horizontal drilling to reach hot rock in the Earth’s interior to produce steam that can generate electricity. Traditional geothermal technology is expensive and thus not competitive with other types of generating technologies. Previous attempts at geothermal projects had failed because they had not taken advantage of oil and gas innovations like horizontal drilling of fiber-optic sensor that have reduced the cost of drilling. Cost declines in horizontal drilling, magnetic sensing and other technologies have helped make the United States a global leader for oil and gas production. Fervo Energy and the Energy Department’s FORGE project are both leveraging hydraulic fracturing techniques to potentially enable enhanced geothermal production in Utah, and many others are lining up in hopes to make geothermal cost-competitive.
