Geothermal energy in the Great Basin of Nevada and adjoining states could produce electricity equal to one-tenth of the current U.S. power supply, the U.S. Geological Survey assessed in a paper released May 22.
The projected 10 percent would be a major increase, as geothermal energy currently generates less than 1 percent of the nation’s power supply. The new assessment, which updates a 2008 USGS assessment, depends on widespread commercial-scale development and continued successful application of evolving and emerging technologies, many of which have been developed over the past several decades in the geothermal and oil and gas industries.
“USGS assessments of energy resources are about the future,” said Sarah Ryker, acting director of the USGS. “We focus on undiscovered resources that have yet to be fully explored, let alone developed. We launched this work in the Great Basin because of the area’s history of geothermal activity – and we found even more potential for baseload power than had previously been known. Leveraging this work along with artificial intelligence and machine learning techniques will help us assess the entire nation’s potential for geothermal energy with greater speed and accuracy.”
Almost all existing geothermal power production comes from hydrothermal systems, in which groundwater naturally circulates through heated rocks. However, there are far more areas where heat is trapped in impermeable rock, where technology is needed to produce geothermal energy. In enhanced geothermal systems, engineers create open fractures in impermeable rock down to 3.7 miles (6 kilometers) below the surface allowing water to circulate and extract heat to generate electricity.
The arid lands of the Great Basin of Nevada and adjoining parts of California, Oregon, Idaho, Wyoming and Utah were the last part of the lower 48 states to be mapped in the 1800s. Mapping and assessing the geological resources of the public lands of the Great Basin through surveys led by Clarence King and John Wesley Powell led to creation of the USGS in 1879.
“Natural resources continue to drive much of the nation’s economy,” Ryker said. “Over our history we have reinvented our techniques for mapping and characterizing resources, and in fact our newest surveys of the subsurface help identify both geothermal and critical mineral resources, and in some cases groundwater.”
The Energy Act of 2020 directed the USGS to assess the entire nation’s potential for geothermal energy. To conduct the assessment the USGS and partners created new heat flow maps, new underground temperature maps, and new methods to estimate energy extraction efficiency and conversion of heat to electricity. Following the Great Basin, the next region to be assessed will be the Williston Basin in North Dakota.
“The new map showing the distribution of enhanced geothermal resources is the culmination of decades of work by the USGS; federal partners, including the Department of Energy; universities and the state geological surveys. The best estimates of available resources reflect the early successes of technology development and application by the geothermal industry,” said Erick Burns, lead author of the assessment.
The assessment finds that with sufficient technological advances in the coming years, there is enough geothermal potential in the Great Basin to meet a large percentage of the nation’s electrical needs. In other words, the heat is there, but greater engineering efficiency is needed to take full advantage of the resource.
The Great Basin Enhanced Geothermal Assessment is available here.
