West Virginia, United States — When you think of geothermal, West Virginia probably doesn’t come to mind. But a team of researchers at Southern Methodist University, funded by Google.org, has found that geothermal resources in the state are capable of supporting large-scale power plants for baseload electricity production.
The SMU Geothermal Laboratory recently said it has increased its estimate of West Virginia’s geothermal generation potential to 18,890 megawatts (assuming a conservative 2% thermal recovery rate). The new estimate represents a 75 percent increase over estimates in MIT’s 2006 “The Future of Geothermal Energy” report and exceeds the state’s total current generating capacity, primarily coal based, of 16,350 megawatts.
Of course, it is highly unlikely that much geothermal will get developed. But the analysis suggests that West Virginia could be a good spot for some large-scale power plants.
The West Virginia discovery is the result of new detailed mapping and interpretation of temperature data derived from oil, gas, and thermal gradient wells – part of an ongoing project to update the Geothermal Map of North America that SMU’s Geothermal Lab Director David Blackwell produced with colleague Maria Richards in 2004. Temperatures below the Earth almost always increase with depth, but the rate of increase (the thermal gradient) varies due to factors such as the thermal properties of the rock formations.
“By adding 1,455 new thermal data points from oil, gas, and water wells to our geologic model of West Virginia, we’ve discovered significantly more heat than previously thought,” Blackwell said. “The existing oil and gas fields in West Virginia provide a geological guide that could help reduce uncertainties associated with geothermal exploration and also present an opportunity for co-producing geothermal electricity from hot waste fluids generated by existing oil and gas wells.”
The high temperature zones beneath West Virginia revealed by the new mapping are concentrated in the eastern portion of the state (Figure 1). Starting at depths of 4.5 km (greater than 15,000 feet), temperatures reach over 150°C (300°F), which is hot enough for commercial geothermal power production.
Traditionally, commercial geothermal energy production has depended on high temperatures in existing subsurface reservoirs to produce electricity, requiring unique geological conditions found almost exclusively in tectonically active regions of the world, such as the western United States. Newer technologies and drilling methods can be used to develop resources in wider ranges of geologic conditions. Three non-conventional geothermal resources that can be developed in areas with little or no tectonic activity or volcanism such as West Virginia are:
- Low-Temperature Hydrothermal — Energy is produced from areas with naturally occurring high fluid volumes at temperatures ranging from 80°C (165°F) to 150°C (300°F) using advanced binary cycle technology. Low-Temperature systems have been developed in Alaska, Oregon, and Utah.
- Geopressure and Co-produced Fluids Geothermal – Oil and/or natural gas produced together with hot geothermal fluids drawn from the same well. Geopressure and Co-produced Fluids systems are currently operating or under development in Wyoming, North Dakota, Utah, Louisiana, Mississippi, and Texas.
- Enhanced Geothermal Systems (EGS) – Areas with low natural rock permeability but high temperatures of more than 150°C (300°F) are “enhanced” by injecting fluid and other reservoir engineering techniques. EGS resources are typically deeper than hydrothermal and represent the largest share of total geothermal resources. EGS is being pursued globally in Germany, Australia, France, the United Kingdom, and the U.S. EGS is being tested in deep sedimentary basins similar to West Virginia’s in Germany and Australia.
“The early West Virginia research is very promising,” Blackwell said, “but we still need more information about local geological conditions to refine estimates of the magnitude, distribution, and commercial significance of their geothermal resource.”
A summary of the research can be found here.
Funding for the research was provided by Google.org’s RE<C initiative. As part of an effort to deploy baseload, renewable energy technologies, Google has made a number of investments in geothermal companies including AltaRock Energy and Potter Drilling.
If you’re in the mood for a longer panel discussion, check out the video below. It features Google’s CEO Eric Schmidt and Google.org’s Dan Riecher talking about the company’s clean energy investment strategy.
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