Geothermal energy – using the heat from deep within the earth as renewable energy to make electricity and heat buildings – has been long on promise and short on delivery. Today, mature technology from the oil and gas industry may be ready to help realize the promise of hot rocks.
For many, “fracking” is a dirty word. Yet hydraulic fracturing of rock formations, combined with horizontal drilling, revolutionized U.S. energy and turned the nation into a net exported of oil and gas and contributed mightily to the decline of U.S. coal. Unfortunately, oil and gas also make major contributions to increasing concentrations of greenhouse gases.
Now, reports Time, former oilman Tim Latimer and his Houston-based Fervo Energy are using horizontal drilling and fracking to dramatically maximize the earth’s hot rocks as an essentially endless source of pollution-free energy. Fervo says, “We employ precision directional drilling technology to drill horizontally in geothermal reservoirs. This enables us to drill multiple wells from a single location, dramatically lowering our surface footprint and reducing drilling risks. Horizontal drilling also facilitates greater access to geologies that were previously challenging to reach, increasing the total resource potential for geothermal energy.”
Conventional water well companies have long used hydraulic fracturing of water-bearing rock strata. It’s a way to increase the water capacity in existing wells for rural farms and homes that rely on them for household and agricultural water. Fervo is also using water pressure to crack open the hot rocks and increase production.
Fervo announced July 18 that it had “completed the well test at its full-scale commercial pilot, Project Red, in northern Nevada,” calling it “the most productive enhanced geothermal system in history. The 30-day well test, a standard for geothermal, achieved a flowrate of 63 liters per second at high temperature that enables 3.5 MW of electric production, setting new records for both flow and power output from an enhanced geothermal system.”
Project Red is expected to connect to the grid later this year, power Google data centers. Coming later is a possible 400-MW Utah project.
In an interview in the Seattle Times, Colorado Gov. Jared Polis said, “There have been enormous technological breakthroughs in geothermal. More geographic areas are now eligible and capable of producing inexpensive geothermal energy. You’re seeing more and more states addressing geothermal opportunities with the urgency that Colorado is.” His state legislature this year approved several geothermal measures, including a regulatory framework. The state’s Oil and Gas Conservation Commission was renamed the Energy and Carbon Management Commission and given oversight of geothermal. Polis is chairman of the Western Governors Association.
CEO and Fervo founder Latimer had worked as a drilling and completion engineer for BHP Billiton in Houston before founding Fervo in 2017. It was at BHP that he began thinking about using horizontal drilling to overcome the major problem with conventional geothermal, which has limited its ability to scale up commercially. Conventional geothermal projects drill vertical wells into often limited hot rock resources.
Latimer told Time, “Traditionally, you would drill simple vertical wells, and you would flow [water] between injection wells and production wells. What’s novel about our site is we drilled down about 8,000 ft., and then we turned and drilled horizontally for 4,000 ft. And then we flowed [water] from one horizontal well to the other across several hundred feet in that high temperature rock 8,000 ft. beneath our feet. That solves some of these economic challenges and allows us to go to deeper places and still make the economics work.”
Latimer told Time, “Our current projects are in states like Utah and Nevada that have good natural geology for geothermal, where we can still drill relatively shallow wells and get to high temperature [rock]. But we’re not limited to those geologies. We’re just starting there first because it’s the low-hanging fruit.”
There is nothing new about geothermal energy. Hot water from the earth has been used for cooking and heating for millennia, including district residential heating in the U.S. and elsewhere in the 1890s, according to Encyclopedia Brittanica. Geothermal electric production began in Italy in the early 20th Century.
New Zealand commissioned commercial geothermal electric production in 1958, and Pacific Gas and Electric in California started the Geysers project in 1960. Tectonically-active Iceland gets most of its electric energy and district heat from hot rocks. Most have used steam directly from the earth, which required some pollution controls because of chemicals in the water that hot rocks were converting to steam. The Fervo project – and other advanced geothermal plays – use Rankin Cycle binary power generation, completely free of emissions.
Today, despite its promise, geothermal electric generation accounts for about 0.4% of U.S. generation. Many experts say that figure could be as high as 20%, if the technology works and is affordable.
Latimer noted, “The world is really big, and the world is really hot. We’ve got billions of years of energy under our feet. It’s all a question about how much you can access economically. We think with existing technology, drilling down to about 4,000 meters [over 13,100 ft.] is probably cost effective.”
–Kennedy Maize