Green Energy
- Geothermal Energy
The Earth as an Energy SourceThe geothermal energy available from the Earth is potentially enormous. A United States Government energy agency estimates that the total energy available from global geothermal resources is approximately 15,000 times the...
- About Green Power Sources
Green power or green energy is classified as the generation of electricity or heat making use of the sources that have minimum carbon footprint. Our planet is constantly getting damaged due to the adverse effects of greenhouse gas emission, solid...
- Geothermal Energy
What is Geothermal Energy? Basically, geothermal energy is the technique of gaining heat as energy source from earth’s surface. In order to produce electricity, most power plants require steam. Geothermal power plants use steam which is produced from...
- Solar Energy: The Energy That Comes From Outer Space
Solar energy is a clean energy as it generates neither greenhouse gas emissions nor pollution. Today, solar energy represents less than 1% of all energy produced by humans and Germany is the country that produces the most. There are two technologies for...
- Ocean Energy
The ocean can produce two types of energy: thermal energy from the sun's heat, and mechanical energy from the tides and waves. Oceans cover more than 70% of Earth's surface, making them the world's largest solar collectors. The sun's...
Green Energy
Geothermal Energy
Geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma.
Almost everywhere, the shallow ground or upper 10 feet of the Earth's surface maintains a nearly constant temperature between 50° and 60°F (10° and 16°C). Geothermal heat pumps can tap into this resource to heat and cool buildings. A geothermal heat pump system consists of a heat pump, an air delivery system (ductwork), and a heat exchanger-a system of pipes buried in the shallow ground near the building. In the winter, the heat pump removes heat from the heat exchanger and pumps it into the indoor air delivery system. In the summer, the process is reversed, and the heat pump moves heat from the indoor air into the heat exchanger. The heat removed from the indoor air during the summer can also be used to provide a free source of hot water.
In the United States, most geothermal reservoirs of hot water are located in the western states, Alaska, and Hawaii. Wells can be drilled into underground reservoirs for the generation of electricity. Some geothermal power plants use the steam from a reservoir to power a turbine/generator, while others use the hot water to boil a working fluid that vaporizes and then turns a turbine. Hot water near the surface of Earth can be used directly for heat. Direct-use applications include heating buildings, growing plants in greenhouses, drying crops, heating water at fish farms, and several industrial processes such as pasteurizing milk.
Hot dry rock resources occur at depths of 3 to 5 miles everywhere beneath the Earth's surface and at lesser depths in certain areas. Access to these resources involves injecting cold water down one well, circulating it through hot fractured rock, and drawing off the heated water from another well. Currently, there are no commercial applications of this technology. Existing technology also does not yet allow recovery of heat directly from magma, the very deep and most powerful resource of geothermal energy.
Many technologies have been developed to take advantage of geothermal energy - the heat from the earth. NREL performs research to develop and advance technologies for the following geothermal applications:
Almost everywhere, the shallow ground or upper 10 feet of the Earth's surface maintains a nearly constant temperature between 50° and 60°F (10° and 16°C). Geothermal heat pumps can tap into this resource to heat and cool buildings. A geothermal heat pump system consists of a heat pump, an air delivery system (ductwork), and a heat exchanger-a system of pipes buried in the shallow ground near the building. In the winter, the heat pump removes heat from the heat exchanger and pumps it into the indoor air delivery system. In the summer, the process is reversed, and the heat pump moves heat from the indoor air into the heat exchanger. The heat removed from the indoor air during the summer can also be used to provide a free source of hot water.
The Earth's heat-called geothermal energy-escapes as steam at a hot springs in Nevada. Credit: Sierra Pacific
Hot dry rock resources occur at depths of 3 to 5 miles everywhere beneath the Earth's surface and at lesser depths in certain areas. Access to these resources involves injecting cold water down one well, circulating it through hot fractured rock, and drawing off the heated water from another well. Currently, there are no commercial applications of this technology. Existing technology also does not yet allow recovery of heat directly from magma, the very deep and most powerful resource of geothermal energy.
Many technologies have been developed to take advantage of geothermal energy - the heat from the earth. NREL performs research to develop and advance technologies for the following geothermal applications:
- Geothermal Energy
The Earth as an Energy SourceThe geothermal energy available from the Earth is potentially enormous. A United States Government energy agency estimates that the total energy available from global geothermal resources is approximately 15,000 times the...
- About Green Power Sources
Green power or green energy is classified as the generation of electricity or heat making use of the sources that have minimum carbon footprint. Our planet is constantly getting damaged due to the adverse effects of greenhouse gas emission, solid...
- Geothermal Energy
What is Geothermal Energy? Basically, geothermal energy is the technique of gaining heat as energy source from earth’s surface. In order to produce electricity, most power plants require steam. Geothermal power plants use steam which is produced from...
- Solar Energy: The Energy That Comes From Outer Space
Solar energy is a clean energy as it generates neither greenhouse gas emissions nor pollution. Today, solar energy represents less than 1% of all energy produced by humans and Germany is the country that produces the most. There are two technologies for...
- Ocean Energy
The ocean can produce two types of energy: thermal energy from the sun's heat, and mechanical energy from the tides and waves. Oceans cover more than 70% of Earth's surface, making them the world's largest solar collectors. The sun's...