Geothermal energy has long been among the more niche methods of renewable power generation. Wind and sunlight affect (almost) every part of the globe. Geothermal power, by contrast, can only be captured in volcanic regions like Iceland, where boiling water rises through the earth to the surface.
Until now, that is.
New technologies and techniques developed over the past decade promise to overcome the traditional limitations of geothermal power. A new clutch of companies and government projects are making the next generation of Enhanced Geothermal Systems (EGS) look like a viable source of renewable energy at a time when the green transition is in desperate need of new ways to cut down on fossil fuel consumption.
A rocky road for EGS
For nearly 50 years, the EGS projects have been working on a way to convert low permeability, hot rock formations into economically viable geothermal reservoirs. Governments in the US and Japan, among others, have invested significantly into EGS projects. However, most have seen mixed results.
Some failed to produce significantly higher energy yields. Others caused bigger problems. In 2017, an EGS plant in South Korea had to close down after likely causing a 5.5 magnitude earthquake as a result of fracking too close to a tectonic fault.
The most successful EGS projects have depended on expanding and stimulating large preexisting faults in the rock. Working in an existing fault line makes it easier to get through the Earth’s crust, allowing deep geothermal springs to reach the surface. It also makes it less likely that you’ll accidentally shake soemthing loose (a technical mining term, I’m pretty sure) and wipe out the neighbouring city. However, the approach isn’t as scalable as the industry would like. Mark McClure, founder of ResFrac, explains that this is because “[stimulating preexisting faults] relies on finding large faults in the subsurface.”
While we aren’t exploiting anywhere near the number of usable faults today, the number of fractures to exploit is, nevertheless, finite. Finding them isn’t always easy either. Despite companies in Germany like Herrenknecht developing novel solutions like “thumper trucks” that could drive around urban areas looking for geothermal faults, most experts agree the more practical solution is find ways of creating new fault lines in the earth to access water warmed by the core.
Fervo’s Project Red and the next steps for geothermal
In late April, Turboden, a company that makes advanced turbines for capturing geothermal energy, announced a new partnership with Fervo Energy.
For Fervo, the relationship is the natural progression of a project that came online in November of 2023, but has been in the works for much longer.
Located in the heart of the Nevada desert, Fervo’s Project Red is a new kind of geothermal power plant, one which uses a new approach to dramatically increase the amount of hot water and steam it can access in an area without naturally-occurring hot springs from volcanic activity.
Project Red’s location in Nevada has seen remarkable success by harnessing techniques borrowed from the oil sector. By creating a 3000 ft lateral (sideways) extension to the bottom, the site achieved by far the highest circulation rates ever recorded between EGS wells.
Drilling and fracking methods have grown increasingly sophisticated since the 2010s, thanks to the boom in oil and gas extraction from shale. The EGS sector has embraced these methods wholeheartedly. As a result, “the techniques that are central to EGS were perfected and brought down significantly in cost,” Wilson Ricks, an energy systems researcher at Princeton University told Knowable Magazine.
Nevertheless, Project Red is a relatively small demonstration of EGS’ potential. The station draws enough steam up from the earth to generate 3.5 megawatts of power. That’s enough to power more than 2,500 homes and more than any other EGS plant today. Nevertheless, it’s significantly smaller than nuclear or coal power plants can generate, and quite a bit less than solar, wind, and traditional geothermal sources.
Now, however, Fervo plans to partner with companies like Turboden to rapidly scale up its technology.
Scaling up Project Red
Situated in southwest Utah, Cape Station is positioned to redefine geothermal energy production with an anticipated total project capacity of approximately 400 MW. If successful, Fervo has claimed the project will represent a “transformative leap towards carbon-free energy solutions.”
The project will begin with an initial 90 MW phase. This includes the installation of three generators with six ORC turbines manufactured by Turboden.
“The success of Cape Station will not only validate the efficacy of EGS technology but also unlock vast potential for future geothermal power projects across the United States,” said the company in a statement.
One 2019 report projected that advances in EGS could result in geothermal power providing about 60 gigawatts of installed capacity to the US grid by 2050. That would account for 8.5% of the country’s electricity. Not only would this be more than 20 times the geothermal capacity of the US today, but the ability to plug up geothermal reservoirs and extract energy when needed could be used to complement more sizable but capricious wind and solar power. It’s just one more piece of the green transition puzzle.
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