Tapping Geothermal Energy in the 21st Century
America’s state geological surveys, under the auspices of the Association of American State Geologists (AASG), are playing a leading role in exploring America’s geothermal potential in the 21st century. AASG and its partners are striving to broaden US energy landscape with environmentally sound, renewable geothermal energy.
To support AASG efforts, the Department of Energy (DOE) provided a three year, $18-million grant as part of the American Recovery and Reinvestment Act (ARRA). Eighty-five percent of the funds supported the 46 participating states in compiling, digitizing, and building metadata for data objects populating the National Geothermal Data System (NGDS).
In support of NGDS – a national, distributed, and interoperable geothermal data system – state geological surveys built four regional data / training centers (Arizona Geological Survey, Kentucky Geological Survey, Illinois State Geological Survey and Nevada Bureau of Mines and Geology) to catalog geothermal data delivered by 46 states surveys.
NGDS serves data to government, NGOs, and industry in order to reshape America’s energy portfolio by tapping into renewable geothermal energy for homes, industry, and communities. Data delivery is complemented by a suite of free desktop tools for mining, sharing, and evaluating data.
Geothermal energy abounds in the US, ranging from low-temperature, ground-source heat that can be extracted to cool homes in the summer and heat them in the winter; to direct use of low- to moderate-temperature water (68 F to 302 F) for homes, industry and commercial uses; to high-temperature systems capable of driving turbines and generating electricity.
U.S. geothermal resources are capable of providing a substantial portion of the nation’s energy needs in the 21st century.
Principal Means of Geothermal Energy Production
- Heat Pump (loop) Technology – highly efficient ground source approach with nationwide potential.
- Direct Use Geothermal – Using moderate temperature waters for direct heating, highest potential is in western US, Alaska and Hawaii.
- Geopressured – Deeply buried, overpressured reservoirs of hot brine largely limited to the Gulf of Mexico and environs.
- Enhanced Geothermal Systems – deep engineered reservoirs requiring the addition of water, potentially nationwide at depths of 6- to 8-km.
- Hydrothermal – Higher temperature sources used to pilot dry steam, flash steam, or binary cycle geothermal power plants principally in the western US, Alaska and Hawaii.
Funding for the National Geothermal Data System
Provided by the Department of Energy (DOE) Geothermal Technologies Program
