Institute for Energy Research (Geothermal energy)
"Geothermal energy is harnessed from the natural heat of the Earth. In some cases, this means tapping extremely hot temperatures via steam at great depths. In others, it involves the use of moderate temperatures at shallow depths. These are known as "heat sinks" and are valuable for their use in creating energy.
Geothermal energy is gaining support as a potential contributor to meeting the growing energy needs of our nation. Today, however, geothermal energy only provides about two-tenths of 1 percent of all the energy consumed in the United States.[i]
To produce electricity, hot water or steam extracted from high temperature geothermal reservoirs in the Earth's crust is piped to steam turbines at electric utilities that drive generators. Moderate-to-low temperature geothermal resources are used for direct-use applications such as space heating or “district†heating, where a sole source of geothermal energy is used to heat multiple buildings or in some cases, a whole community.
Lower-temperature, shallow-ground geothermal resources are used by geothermal heat pumps to heat and cool individual buildings. Such uses of geothermal energy are becoming increasingly popular as an option for new home construction by those who seek long-term energy savings, as heating and cooling via a geothermal heat pump is very cost-effective.
As of April 2011, only nine states in the United States have geothermal power plants: California (with 48), Nevada (21), Utah (3), Alaska (1), Idaho (1), Hawaii (1), New Mexico (1), Oregon (1), and Wyoming (1). Total U.S. geothermal capacity is rated at 3,102 megawatts (MW).
Geothermal power plants do not burn fuel to produce electricity, so their emission levels are very low. They typically release less than 1 percent of the carbon dioxide emissions of a fossil fuel plant and about 3 percent of their acid rain emissions." more
|
