Geothermal Energy in Virginia

in Virginia, geothermal heat flow reaching the surface (measured in milliwatts/sqare meter) is highest near Bath County
in Virginia, geothermal heat flow reaching the surface (measured in milliwatts/square meter) is highest near Bath County
Source: Department of Energy, Geothermal Heat Flow and Existing Plants

Virginia has 20 thermal springs, ranging in temperature from 60-106°F. The water in Virginia's thermal springs is rainwater which is heated by the geothermal gradient as it travels underground before resurfacing.1

The state's greatest geothermal asset is the stable-temperature bedrock, which averages around 55°F near the surface. In the winter, that temperature is warm. In the summer, 55°F is cool.

Virginia lacks the geothermal potential for generating electricity as California does at The Geysers, but there is great potential for heating/cooling buildings.

Geothermal energy is a renewable resource that could reduce the use of fossil fuels that produce greenhouse gas emissions. Ground source heat exchangers can use standard heat pump technology, but rely upon fluid moving through pipes in the ground rather than exchange heat with the air. In contrast to air-based heat exchangers, the fluid is always 55°F.

Deep wells into drill into hard, impermeable rocks can be connected through horizontal drilling. Since water can be pumped underground, existing groundwater is no longer required. In northern Nevada, in a location without geysers and hot springs, the Project Red site can generate 3.5 megawatts of electricity from wells drilled 7,700 feet deep. The US Department of Energy calculated that 65 million homes could be powered eventually by 90 gigawatts of geothermal electricity. In 2022, geothermal power plants generated less than four gigawatts.2

geysers such as Old Faithful in Yellowstone National Park are generated by water heated at depth, reaching the boiling point, and then surging to the surface
geysers such as Old Faithful in Yellowstone National Park are generated by water heated at depth, reaching the boiling point, and then surging to the surface

Temperature increases at depth. The geothermal gradient averages 25–30°C/km, or 15°F/1,000 feet in depth. Geothermal wells can be drilled deeper in order to access warmer rocks below the surface.3

temperature at depth, 200m below ground surface
temperature at depth, 200m below ground surface
Source: Virginia Department of Energy, Geothermal Resources for the Eastern United States (2013)

heat flow, the ability of bedrock to conduct heat, is greatest near Bath County
heat flow, the ability of bedrock to conduct heat, is greatest near Bath Countye
Source: Virginia Department of Energy, Geothermal Resources for the Eastern United States (2013)

Radioactive elements in granitic plutons generate heat more than other bedrock, and plutons buried deep below the Coastal Plain sediments may offer geothermal potential for deep wells. The US Department of Energy has provided over $7 million to West Virginia University, so it can drill 15,000 feet deep in 2023 to assess if deep wells in the eastern United States could provide a reliable supply of geothermal energy near Morgantown.4

geothermal energy potential in the United States
geothermal energy potential in the United States
Source: US Energy Information Administration, Geothermal Explained: Where Geothermal Energy Is Found

The US Department of Energy launched the Enhanced Geothermal Shot in 2022, seeking to lower costs for enhanced geothermal systems by 90% by 2035.5

Traditionally, geothermal systems are designed with heat exchangers to transfer underground heat (or coolness) to enclosed spaces in buildings on the surface. An additional possibility is to use fracking technology to pump water/fluids underground when solar/wind systems generate excess electricity, then extract the fluids when there demand for electricity increases at a different time of day.

If the underground reservoir is pressurized by the pumping, then the fluid could be released as needed to create an artesian flow at the surface strong enough to power a generator producing electricity. Such a geothermal system could serve as a battery, as well as a source of heat. Virginia lacks above-average temperatures underground, but may have geologic formations suitable for creating a geothermal battery system.6

Thermal Springs in Virginia

a geothermal battery would store fluids in pressurized geologic formations, then extract the fluids to power a generator
a geothermal "battery" would store fluids in pressurized geologic formations, then extract the fluids to power a generator
Source: US Department of Energy, Geothermal Energy: A Glance Back and a Leap Forward

Links

References

1. "Thermal Springs in the United States," National Oceanographic and Atmospheric Service (NOAA), National Geophysical Data Center, http://maps.ngdc.noaa.gov/viewers/hot_springs/; "Thermal Springs Of The United States And Other Countries Of The World," Professional Paper 492, US Geological Survey (USGS),1965, pp.43-44, http://pubs.usgs.gov/pp/0492/report.pdf (last checked September 12, 2022)
2. "Average Annual Temperature for Each US State," Current Results, https://www.currentresults.com/Weather/US/average-annual-state-temperatures.php; "What is Geothermal Energy?," Virginia Department of Energy, https://energy.virginia.gov/geology/Geothermal.shtml;"Startup claims breakthrough in turning the earth’s heat into clean power," Canary Media, July 18, 2023, https://www.canarymedia.com/articles/geothermal/startup-claims-breakthrough-in-turning-earths-heat-into-clean-power; "DOE Analysis Highlights Opportunities to Expand Clean, Affordable Geothermal Power," US Department of Energy, January 25, 2023, https://www.energy.gov/eere/articles/doe-analysis-highlights-opportunities-expand-clean-affordable-geothermal-power (last checked July 21, 2023)
3. "Explore the Energy Glossary," SLB, https://glossary.slb.com/Terms/g/geothermal_gradient.aspx (last checked July 24, 2023)
4. "Geothermal gradient," AAPG Wiki, American Association of Petroleum Geologists, https://wiki.aapg.org/Geothermal_gradient; "Drilling For Geothermal Data in West Virginia," West Virginia University, https://geothermal.wvu.edu/ (last checked September 12, 2022)
5. "DOE Launches New Energy Earthshot to Slash the Cost of Geothermal Power," US Department of Energy, September 8, 2022, https://www.energy.gov/articles/doe-launches-new-energy-earthshot-slash-cost-geothermal-power (last checked September 13, 2022)
6. "This Texas geothermal startup is storing energy in the ground," Canary Media< April 4, 2023, https://www.canarymedia.com/articles/geothermal/this-texas-geothermal-startup-is-storing-energy-in-the-ground (last checked April 5, 2023)

the US Department of Energy launched an earthshot in 2022 to cut the costs of geothermal energy
the US Department of Energy launched an earthshot in 2022 to cut the costs of geothermal energy
Source: US Department of Energy, Enhanced Geothermal Shot infographic


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