Enhanced Geothermal Technology Cracks The 24/7 Energy Code
The US has vast geothermal energy resources, but most of it is trapped within stubborn rock formations, beyond reach. That is about to change. The US Department of Energy has been supporting R&D on a new approach to 24/7 thermal energy called enhanced geothermal systems, and one of its private sector partners just pulled in $138 million in new funding to complete the construction of two new geothermal-fueled power plants in the US. At least five more could soon be in the pipeline, with more to come overseas.
The Long Road To Enhanced Geothermal Technology…
Unlike other renewable energy sectors, the US geothermal field has been slow on the uptake. The domestic wind and solar industries sprinted ahead over the past 10 years, but US geothermal stakeholders were more or less in a holding pattern. For a while back there, the Energy Department was focused was on just keeping the industry afloat by supporting R&D for export.
Things began to heat up in 2015, when the Energy Department began organizing a major new research facility aimed at developing enhanced geothermal systems. Loosely speaking, the technology involves building underground reservoirs in rock formations, to access thermal energy that would otherwise be inaccessible.
“Enhanced Geothermal Systems (EGS) hold the potential to power tens of millions of American homes and businesses,” explains the Energy Department’s Geothermal Technologies Office.
That’s easier said than done, but the prize is a big one. Spreading more geothermal love around the US will help send more fossil power plants to the dustbin of history more quickly, hopefully in time to avoid a global climate catastrophe.
In particular, the ability to exploit more underground thermal energy could upend the energy profile in West Virginia, which has just begun to explore the full extent of its renewable underground resources.
The main challenge is engineering a reservoir deep underground where nobody can see it. Enhanced reservoirs don’t resemble anything like a conventional reservoir. The idea is to create networks of fractures in basement rock formations, and the first big research challenge is how to stabilize the new fractures.
“This critical knowledge will be used to design and test a methodology for developing large-scale, economically sustainable heat exchange systems, paving the way for a rigorous and reproducible approach that will reduce industry development risk and facilitate EGS commercialization,” GTO explains. “The R&D activities include innovative drilling techniques, reservoir stimulation techniques, well connectivity and flow-testing efforts, and other related activities.”
“GTO actively supports R&D initiatives that guide enhanced geothermal toward a commercially viable platform by 2030, including technology validation, cost reduction, and improved performance,” they add.
…Just Got A Lot Shorter
One significant development in the Energy Department’s geothermal program is the new Frontier Observatory for Research in Geothermal Energy (aka FORGE), an underground laboratory in Utah sponsored by the agency in partnership with the University of Utah. Planning for the project took years and it won’t be fully completed until 2024, but as of 2020 FORGE was already engaging stakeholders in preliminary work.
“Near term goals are aimed at perfecting drilling, stimulation, injection-production, and subsurface imaging technologies required to establish and sustain continuous fluid flow and energy transfer from an EGS reservoir,” the Energy Department explains.
FORGE hopped across the CleanTechnica radar last year, when we took note of the geothermal startup Fervo Energy, which has been developing its EGS technology with an assist from the Energy Department funding pot.
One leg up occurred in 2019, when the Energy Department’s cutting-edge funding office, ARPA-E, awarded the company $4.5 million in funding for a project called Long duration In-reservoir Energy Storage and Load-Following, Dispatchable Geothermal Generation.
“The FervoFlex TM technology effectively enables Fervo to operate their assets to achieve multi-day energy storage attributes in addition to the traditional benefits of clean, firm geothermal power,” ARPA-E noted.
Last year, the University of Utah included Fervo in a round of $49 million in funding for 17 R&D projects at FORGE. Fervo and the University of Texas at Austin split a $12 million out of that pot for something called Stimulation and Configuration of the Well(s).
Geothermal Money Comes To Money
Meanwhile, Fervo is already on track to commercialize its enhance geothermal system. The clean tech incubator Elemental Excelerator was an early-on supporter of Fervo, partly on account the firm’s potential for bringing its technology to market quickly.
Elemental’s former Director of Energy Innovation, Nneka Uzoh, explained the interest in Fervo to CleanTechnica last year.
“A lot of what we’re looking at is drive by market need and what can be scaled. The other part is focused on supporting [the technology] with partners in utilities, cities and towns. So, it has to be at the commercialization stage,” said Uzoh, who is also the founder of GreenTech Noir and is currently the Senior Vice President at Aligned Climate Capital.
“There is no shortage of geothermal solutions and many of them are academically and technically advanced but the cost is incredibly high,” she added. “They are capital intensive and require a great number of stakeholders, so they are not the best fit for us. But Fervo stood out because they were a startup that was quick as relates to rollout.”
That was last year. Last week, Fervo wrapped up the aforementioned a new $138 million round of funding spearheaded by the “deep tech” firm DCVC.
For those of you keeping score at home, other new investors were the Canada Pension Plan Investment Board (aka CPP Investments), Liberty Energy, Macquarie, Grantham Foundation for the Protection of the Environment, Impact Science Ventures, and Prelude Ventures. Existing investors also chipped in, including Elemental Excelerator and the well-known Breakthrough Energy Ventures along with Capricorn’s Technology Impact Fund, Congruent Ventures, 3X5 Partners, and Helmerich & Payne, along with Elemental Excelerator.
“Fervo’s innovations include technologies such as advanced computational models, horizontal drilling, and distributed fiber optic sensing that have been developed with partners including Schlumberger, ARPA-E, and the Lawrence Berkeley National Lab,” Fervo said, noting that the new funding will enable it to complete work on a geothermal power plant in Nevada, commissioned by Google.
How Does It Work?
Fervo drew heavily from the fossil energy skill set to develop its new geothermal technology, which explains why some of language on its website sounds familiar.
“Fervo’s horizontal well design connects subsurface wells with a set of hydraulically conductive fractures surrounded by impermeable rock. These fractures act as flow pathways, providing contact areas with the geothermal reservoir to enable sustained heat recovery, and the low-permeability rock prevents fluid leak- off,” the company explains.
“Charging and discharging cycles are performed by controlling the injection and production well flow rates and pressures to deliver flexible generation profiles in response to grid demands and time-shift energy at high round-trip efficiencies,” they add.
Next steps for Fervo involve fine tuning a fiber-optics tool that will enable the geothermal researchers to see what is going on underground, so stay tuned for more on that.
Follow me on Twitter @TinaMCasey.
Image (cropped): EGS infographic via US Department of Energy.
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