Geothermal Energy is an enormous underused heat and power resource that is clean, reliable and homegrown. The energy is derived from the natural heat of the earth. This heat is brought to the surface as steam or hot water created when water flows through heated permeable rock. It's used directly for space heating in homes and buildings or converted to electricity. Most of the country's geothermal resources are located in the western U.S.
Geothermal energy has been used to provide electricity in the United States since 1960. .
The primary use of geothermal resources is in district, space heating, greenhouses, and aquaculture facilities. A 1996 survey found that these applications were using nearly 5.8 billion mega joules of geothermal energy each year, the energy equivalent of nearly 1.6 million barrels of oil. In the U.S. there are more than 120 operations, with hundreds of individual systems at some sites that are using geothermal energy for district and space heating. District systems distribute hydrothermal water from one or more geothermal wells through a series of pipes to several individual houses and buildings. Space heating uses one well per structure. In both types, the geothermal production well and distribution piping can help replace the fossil fuel burning heat source of the traditional heating system. Geothermal district heating systems can save consumers 30% to 50% of the cost of natural gas heating. .
Greenhouses and aquaculture are the two primary uses of geothermal energy in the agribusiness industry. Most greenhouse operators estimate that using geothermal resources instead of traditional energy sources saves about 80% of fuel costs and about 5% to 8% of total operating costs. The relatively rural location of most geothermal resources also offers advantages, including clean air, few disease problems, clean water, a stable workforce, and, often, low taxes. Dehydration or the drying of vegetable and fruit products is the most common industrial use of geothermal energy.