Logical4u
Geothermal plants are great. They can only be built close to fault lines where magna is relatively close to the surface (or volcanic vents).
Wrong, completely wrong.
It is true the costs are comparable for "those areas". What about the areas hundreds of miles away from geothermal pockets? There are limits to wind, solar, tidal, hydro units (they are not reliable generators in "most" areas); there is a need for baseline plants (plants that generate 24/7 in large amounts), baseline plants away from geothermal pockets are steam driven (heated by coal or nuclear reaction). Most people do not understand our electricity cannot be stored. It must be made (converted), constantly. It becomes more difficult to transmit over increasing distances, that makes production in limited areas, unreasonable.
Environmentalists want to declare all the progress we have made as terrible and "poluting", but very few want to live without all the wonders electricity provides (pumping clean water to our homes and "waste" away from our homes). They want other people to sacrifice without demonstrating how living without the "modern conveniences" is beneficial to anyone.
3.1. What is the official government estimate of potential geothermal electric resources in the U.S.?
3.2. Are there other examples of how geothermal resources are utilized?
3.3. How much energy is geothermal electricity capable of supplying to the U.S?
3.4. Where are geothermal resources located?
3.5. "How much electricity can geothermal supply worldwide?"
3.1. What is the official government estimate of potential geothermal electric resources in the U.S.?
The heat of the Earth is considered limitless; its use is only limited by technology and the associated costs. Technology development and further studies are expected to show even greater potential, but here we have cited the first part of a new assessment released in September 2008 by the U.S. Geological Survey (USGS). (1) The report focuses on 13 western states and breaks the geothermal estimate into three categories:
Identified Geothermal Systems: The resource is either liquid or vapor dominated and has moderate to high temperature. The resource is either producing (the reservoir is currently generating electric power), confirmed (the reservoir has been evaluated with a successful commercial flow test of a production well), or potential (there are reliable estimates of temperature and volume for the reservoir but no successful well tests to date).
Undiscovered Geothermal Resources: Geothermal resources were assessed for the same 13 states in which the identified resources are located. The assessment was based on mapping potential via regression analysis.
Enhanced Geothermal Systems (EGS): Resource probability in regions characterized by high temperatures but low permeability and lack of water in rock formations.
The assessment estimates power generation potential as follows:
Identified Geothermal Systems: 3,675 MWe (95% probability) to 16,457 MWe (5% probability)
Undiscovered Geothermal Systems: 7,917 MWe (95% probability) to 73,286 MWe (5% probability)
EGS: 345,100 MWe (95% probability) to 727,900 MWe (5% probability).
The USGS assessment evaluates geothermal resources in the states of Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. The assessment identified 241 moderate-temperature (90 to 150°C; 194 to 302°F) and high-temperature (greater than 150°C) geothermal systems located on private and public lands in these states. Geothermal systems located on public lands closed to development, such as national parks, were not included in the assessment. Electric-power generation potential was also determined for several low-temperature (less than 90°C) systems in Alaska for which local conditions make electric power generation feasible.
Although the assessment only accounted for large-scale geothermal power production, the USGS is also in the process of updating information about direct use, small power, oil and gas co-production and geopressured resources and the potential energy contribution of those portions of the geothermal resource base are not included in the estimates above.
The USGS assessment is the first new national geothermal resource assessment since 1979, when USGS released its last geothermal resource estimate, Circular 790. A new component of the 2008 assessment is the inclusion of production potential of EGS techniques. For more information on the USGS assessment, please visit
USGS Release: Substantial Power Generation from Domestic Geothermal Resources (9/29/2008 5:06:28 PM).
In 2006, Massachusetts Institute of Technology (MIT) prepared an analysis of the future geothermal potential in the U.S. The report estimated that geothermal systems could produce 100 GWe in the next 50 years with a reasonable investment in R&D. The report, The Future of Geothermal Energy, is available at
http://geothermal.inel.gov/publicat....energy.gov/geothermal/future_geothermal.html
3.2. Are there other examples of how geothermal resources are utilized?
Distributed generation: Distributed generation facilities such as those at Chena Hot Springs in Alaska, the Burgett greenhouse in New Mexico, and the Oregon Institute of Technology are examples of small-scale electricity produced to cover the electricity needs of each facility. Energy not being used by the facility is sold back to the grid.
Figure 15: Chena Hot Springs, AK, Gains Distributed Generation Begins in 2006
Geopressured resources: Geopressured resources are deep reservoirs of high-pressured hot water that contain dissolved methane. The Department of Energy built a demonstration plant in Texas which produced electricity from geopressured resources, pictured below. Preliminary testing (Phase 0) of Well No. 2 took place during 1979, reservoir limits testing during 1980 (Phase I), and long-term testing (Phase 11) was conducted during 1981–1983. The plant was dismantled after being deemed a success.( 2)
Figure 16: Geopressured Demonstration Plant in Texas
Co-production geothermal fluids: Usable geothermal fluids are often found in oil and gas production fields. The Southern Methodist University Geothermal Energy Program has identified thousands of megawatts of potential energy production from hot water being co-produced with oil and gas. There are presently two geothermal co-production demonstrations underway supported by the U.S. DOE, at the Rocky Mountain Oil Test Center in Wyoming and the Jay oil field in Florida. ( 3)
Enhanced Geothermal Systems (EGS): EGS involves developing tools and techniques that will allow geothermal production by artificially creating permeability in hot rock and introducing water (or another working fluid) to extract the heat. While reaching the full potential of EGS may take a decade or more to realize, there are many aspects of EGS that are already being applied. In California at The Geysers field—the oldest geothermal field in the U.S. and the largest geothermal venture in the world—operators have expanded the capacity of wells by injecting millions of gallons of reclaimed wastewater into the geothermal reservoir. Some experts call the Geysers wastewater project the first large-scale EGS project. There are several EGS projects that are already, or will soon, produce power:
Soultz project, in France, a 1.5-MW EGS plant already in operation
Landau project, in Germany, a 2.5-MW operational plant
Paralana, in Australia, a 7–30-MW plant in drilling stages
Cooper Basin, in Australia, a 1-MW showcase plant will be operational in 2008 and a 250–500-MW plant in drilling stages, expected to have the first 50 MW EGS plant operating as early as 2011–2012
Desert Peak, in the U.S. ( Nevada), in planning stages, the expansion of an existing natural geothermal field
In October of 2008, the U.S. Department of Energy selected four new cooperative projects with the U.S. geothermal industry for EGS systems demonstrations in the U.S. which it hopes will lead to technology readiness by 2015. For more information on the DOE effort visit:
Geothermal Technologies Program: Enhanced Geothermal Systems. Also, the International Partnership for Geothermal Technology provides information about efforts to developed advanced technologies for EGS and related areas. You can visit their web site at:
IPGT | International Partnership for Geothermal Technology.
Figure 17: Soultz, France, 1.5-MW EGS Power Plant
3.3. How much energy is geothermal electricity capable of supplying to the U.S?
In 2006 the National Renewable Energy Laboratory (NREL) released a report, Geothermal—The Energy Under Our Feet, which estimates domestic geothermal resources. The report estimates that 26,000 MW of geothermal power could be developed by 2015, with direct use and heat pumps contributing another 20,000 MW of thermal energy. The report suggests that by 2025 more than 100,000 MW of geothermal power could be in production, with direct use and heat pumps adding another 70,000 MW of thermal energy. (4)
As the report concludes, “these estimates show the enormous potential of the U.S. geothermal resource.” For power production, the report includes specific estimates of the potential for identified resources, deep geothermal co-produced fluids and geopressured resources, and EGS. In addition, the report examines the potential for geothermal direct use and geothermal heat pumps.
The report does not include hidden or undiscovered geothermal systems, which the USGS report estimates have substantial energy potential. Nor does the report specifically examine small power systems (distributed generation).
For more information on the NREL report, please visit
http://www1.eere.energy.gov/geothermal/pdfs/40665.pdf.
Geothermal Energy Association
