Published on October 27th, 2011 | by Charis Michelsen7
Geothermal Energy Could Power Entire U.S. (Maybe)
October 27th, 2011 by Charis Michelsen
Google is dipping its toes in renewable energy – according to Science Daily, it provided a grant to SMU Geothermal Laboratory which indicates a pretty hefty amount of geothermal power lurking across the United States. The total amount of available power is claimed to be more than three million megawatts (current coal power plants produce 300,000 megawatts, for the curious). Maps are viewable on Google Earth (where else?) and SMU believes that they are accessible with current technology.
We Know More Than Before!
Traditional geothermal production in the U.S. is in the western part of the country, where there’s more tectonic activity, but the new research has refined the geothermal map. Using nearly 35,000 data points (twice the number in a previous survey, and primarily drawn from oil and gas drilling), more local variations were found for temperatures at depth. The eastern half of the country seems to hold much more potential than previously thought – through the Appalachians, for example.
The new data points were used for in-depth analysis (more information means a better overall picture, usually) to create heat flow maps and temperature-at-depth maps from 11,500 to 31,000 feet. Surprisingly, some of the areas of the eastern part of the U.S. actually appear to be hotter than the areas in the Western U.S. currently generating the bulk of American geothermal power.
The new study does take into account some practical limitations – no geothermal power plants are going to be in cities or national parks, for instance – and doesn’t analyze heat below 21,500 feet of crust. With those guidelines, the study stays within newly proposed international standards for geothermal resource potential.
SMU Hamilton Professor of Geophysics David Blackwell, half of the research team leadership, still feels that the full potential of American geothermal energy has yet to be explored:
“This assessment of geothermal potential will only improve with time,” said Blackwell. “Our study assumes that we tap only a small fraction of the available stored heat in the Earth’s crust, and our capabilities to capture that heat are expected to grow substantially as we improve upon the energy conversion and exploitation factors through technological advances and improved techniques.”
The new version of the map, produced by Blackwell and research partner Geothermal Lab Coordinator Maria Richards, is not the first SMU has offered. Their earlier survey has been the national standard for evaluating heat flow, temperature, and thermal conductivity since it was published in 2004.
We Can Do More Than Before!
More refined information isn’t the only reason for improved geothermal prospects; the technology is also advancing. New drilling methods, for instance, can be used in a wider range of geologic conditions. Three more specific examples of new technology used to generate geothermal energy under previously unusable conditions, also according to Science Daily, are:
- 1. Low Temperature Hydrothermal — Energy is produced from areas with naturally occurring high fluid volumes at temperatures ranging from less than boiling to 150°C (300°F). This application is currently producing energy in Alaska, Oregon, Idaho and Utah.
- 2. Geopressure and Coproduced Fluids Geothermal — Oil and/or natural gas are produced together with electricity generated from hot geothermal fluids drawn from the same well. Systems are installed or being installed in Wyoming, North Dakota, Utah, Louisiana, Mississippi and Texas.
- 3. Enhanced Geothermal Systems (EGS) — Areas with low fluid content, but high temperatures of more than 150°C (300°F), are “enhanced” with injection of fluid and other reservoir engineering techniques. EGS resources are typically deeper than hydrothermal and represent the largest share of total geothermal resources capable of supporting larger capacity power plants.
As the tools available continue to improve, geothermal energy comes under more and more consideration as a source of clean, renewable power. The SMU assessment was specifically aimed toward evaluating non-conventional resources, and its results were perhaps unexpectedly positive.
Karl Gawell, executive director of the Geothermal Energy Association, has nothing but praise for both Google and the SMU:
“Once again, SMU continues its pioneering work in demonstrating the tremendous potential of geothermal resources. Both Google and the SMU researchers are fundamentally changing the way we look at how we can use the heat of the Earth to meet our energy needs, and by doing so are making significant contributions to enhancing our national security and environmental quality.”
Whether SMU’s new geothermal energy sources are viable or not remains to be seen – and depending on the exact locations of proposed plants, there could be an outbreak of NIMBY. How would you feel about a geothermal plant in your community’s back yard? Let us know in the comments, below.
Source | Image: Science Daily