The Department of Energy is providing $74 million for a geothermal pilot project that harnesses heat miles underground to unlock massive amounts of renewable electricity.
The funding announced last week will be used for up to seven pilot projects. Funders will test whether a new kind of geothermal technology called EGS (Enhanced Geothermal Systems) could be an economical way to convert heat into electricity almost anywhere on Earth.
This is part of the Biden administration’s commitment to halving greenhouse gas emissions by 2030 and transitioning to a zero-carbon grid by 2035. Geothermal energy has been an effective method of generating electricity for decades, but is currently restricted to some areas. Active volcanoes, hot springs, geysers.
DOE funding is aimed at accessing heat buried deep within the earth that is theoretically available everywhere. While current geothermal power plants use hot water from geysers to power turbines, ESG effectively builds man-made geysers. In this method, a stream of cold, high-pressure water is injected into the rock, where it is heated and then piped back to the ground to generate carbon-free electricity.
According to the DOE, the United States has over 5 terawatts of thermal resources. This is enough power to meet the world’s power demand. A recent analysis of EGS predicts that the successful development of EGS could deliver 90 gigawatts of power to the US grid by 2050.
“The appeal of EGS over conventional geothermal systems is that it uses heat everywhere, on all continents, at depths of 5 to 15 kilometers,” says the Institute of Energy and Earth Sciences at the University of Utah. Research Professor Stuart Simmons said. “This funding will provide a seed investment to further de-risk the technology, [help] its geographical spread. ”
Like gas and coal power plants, geothermal systems can meet fluctuating power demands. This complements solar and wind power, which are vulnerable to changing weather conditions, said Mark White, a geothermal expert and mechanical engineer at the Pacific Northwest National Laboratory. For example, an EGS system could theoretically increase output during peak demand periods by increasing the flow of water injected into the rock.
Simmons says the biggest challenge in building a commercially viable EGS is the high cost of drilling. Developers would have to dig miles deep into the earth’s crust, requiring extremely hot fluids for efficient power generation, making the project prohibitively expensive.
Minimizing drilling costs is key to achieving the DOE’s goal of reducing the cost of geothermal power by 90% to $45 per MWh by 2035.
Both Simmons and White say costs have come down in recent years. For his major EGS test project, Utah Forge, he found ways to reduce drilling time by 20 to 30 percent, leading to cost savings, said Simmons, who also works on the project.
This method is similar to that used by the oil and gas industry for fracking. Developers first dig a well and inject high-pressure water to break up underground rocks. A second well then pumps water. This water is heating up as it flows through the cracks.
A successful EGS project will require multiple fracturings to connect these two wells. This is a drilling technique that the hydraulic fracturing industry mastered nearly a decade before him.
Enhanced geothermal systems could offer a valuable opportunity for the oil and gas industry to use existing expertise and capital investments to transition to low-emission operations, White said.
“We see a lot of these oil companies are very interested in geothermal right now. [fracking] geothermal expertise,” he said.
Reprinted from E&E News with permission of POLITICO, LLC. Copyright 2023. E&E News provides essential news for energy and environmental professionals.
