Facts about Geothermal
In 2007, the world had a global capacity for 10 GW of electricity generation and an additional 28 GW of direct heating, including extraction by geothermal heat pumps (Fridleifsson et al.
The type of source impacts which method can be used for capturing geothermal energy for production of electricity or other practical use.
Most geothermal power plants planned for construction are binary cycle.
Geothermal energy/power is produced by tapping into the thermal energy created and stored within the earth.
From an economic view, geothermal energy is price competitive in some areas.
California produces the most electricity from geothermal (EIA 2011), with installed capacity estimated to 2,732.2 MW in 2012, while the USA’s second leading geothermal state, Nevada, reached 517.5 MW (GEA 2013).
The world's biggest producer of electricity from geothermal sources is the Philippines.
The development of binary cycle power plants and improvements in drilling and extraction technology enable enhanced geothermal systems over a much greater geographical range (MIT 2006).
The world's biggest geothermal energy resources are in China; the second-largest ones in Hungary.
In 2010, the United States led the world in geothermal electricity production with 3,086 MW of installed capacity from 77 power plants (Holm et al.
Prince Piero Ginori Conti tested the first geothermal power generator on 4 July 1904, at the same Larderello dry steam field where geothermal acid extraction began.
Four basic designs are typically utilized for geothermal heat pump systems: Horizontal closed loop systems, vertical closed loop systems, pond/lake closed loop systems, and the open-loop option.
The completing of a geothermal plant takes significant time (four to eight years) versus the times for wind or solar, and there is a lack of transmission lines (EIA 2011).
The thermal efficiency of geothermal electric plants is low, around 10–23%, because geothermal fluids do not reach the high temperatures of steam from boilers.
Estimates of exploitable worldwide geothermal energy resources vary considerably.
Some areas have geothermal resources that can be used directly for heating purposes.
Given enough excess capacity, geothermal energy can also be sold to outside sources such as neighboring countries or private businesses that require energy.
The International Geothermal Association (IGA) reported in 2010 that 10,715 megawatts (MW) of geothermal power in 24 countries was online and was expected to generate 67,246 GWh of electricity in 2010 (Holm et al.
Upper estimates of geothermal resources assume enhanced geothermal wells as deep as 10 kilometers (6 mi), whereas existing geothermal wells are rarely more than 3 kilometers (2 mi) deep (Fridleifsson 2008).
There also are several environmental concerns behind geothermal energy.
Enhanced geothermal systems allow the capturing of heat even in these dry locations.
The Basin and Range geologic province in Nevada, southeastern Oregon, southwestern Idaho, Arizona, and western Utah is now an area of rapid geothermal development.
Geothermal thermal energy is used to generate electricity typically via a well that is drilled into an underground reservoir of water that can be as hot as 371 degrees Celsius (700 Fahrenheit).
The hot fluid from geothermal reservoirs is passed through a heat exchanger, which transfers heat to a separate pipe containing fluids with a much lower boiling point, and thus more easily converted to steam.
The Philippines is the second highest producer, with 1,904 MW of capacity online in 2010; Geothermal power makes up approximately 27% of Philippine electricity generation (Holm et al.
A deep geothermal well was used to heat greenhouses in Boise in 1926, and geysers were used to heat greenhouses in Iceland and Tuscany at about the same time (Dickson and Fanelli 2004).
The modern practice of injecting cooled geothermal fluids back into the Earth to stimulate production has the side benefit of reducing this environmental risk.
Estimates of the potential for electricity generation from geothermal energy vary sixfold, from .035 to 2TW depending on the scale of investments (Fridleifsson 2008).
Geothermal wells do release greenhouse gases trapped deep within the earth, but these emissions are much lower per energy unit than those of fossil fuels.
In 2007, the world had a global capacity for 10 GW of electricity generation and an additional 28 GW of direct heating, including extraction by geothermal heat pumps (Fridleifsson et al.
Geothermal heat pumps are also known as ground-source heat pumps, GeoExchange heat pumps, earth-coupled heat pumps, and water-source heat pumps (USDOE 2012).
Geothermal energy is considered "sustainable energy" and a "renewable energy resource" because the thermal energy is constantly replenished and the extraction by people is small relative to total content (Ryback 2007).
The admission fees for these baths probably represent the first commercial use of geothermal power.
In 2004, 200 petajoules (56 TWh) of electricity was generated from geothermal resources, and an additional 270 petajoules (75 TWh) of geothermal energy was used directly, mostly for space heating.
The four basic means for capturing geothermal energy for practical use are geothermal power plants (dry steam, flash steam, binary cycle), geothermal heat pumps, direct use, and enhanced geothermal systems.
Geothermal electric plants were traditionally built exclusively on the edges of tectonic plates where high temperature geothermal resources are available near the surface.
The largest group of geothermal power plants in the world is located at The Geysers.
The International Centre for Geothermal Research (IGC), a German geosciences research organization, is largely focused on geothermal energy development research.
Later, in 1911, the world's first commercial geothermal power plant was built there.
Geothermal power plants use the heat from deep inside the Earth to pump hot water or hot steam to the surface to power generators.
Enhanced geothermal systems can trigger earthquakes as part of hydraulic fracturing.
Enhanced geothermal systems (EGS) actively inject water into wells to be heated and pumped back out.
Direct geothermal heating systems contain pumps and compressors, which may consume energy from a polluting source.
Geothermal plants use 3.5 square kilometers (1.4 sq mi) per gigawatt of electrical production (not capacity) versus 32 square kilometers (12 sq mi) and 12 square kilometers (4.6 sq mi) for coal facilities and wind farms respectively (Lund 2007).
A geothermal heat pump (GHP) can be used to extract heat from the ground to provide heat and cooling for buildings.
Geothermal energy is used commercially in over 70 countries (MIT 2006).
The geothermal energy of the Earth's crust originates from the original formation of the planet and from radioactive decay of minerals, resulting in continual production of geothermal energy below the earth's surface.
The world's oldest geothermal district heating system in Chaudes-Aigues, France, has been operating since the 14th century (Lund 2007).
The design selected for generating power from geothermal energy depends on the temperature, depth, and quality of the water and steam in the area.
In 1892, America's first district heating system in Boise, Idaho was powered directly by geothermal energy, and was copied in Klamath Falls, Oregon in 1900.
Outside of the seasonal variations, the geothermal gradient of temperatures through the crust is 25–30 °C (77–86 °F) per kilometer of depth in most of the world.
Geothermal thermal energy is used to generate electricity typically via a well that is drilled into an underground reservoir of water that can be as hot as 371 degrees Celsius (700 Fahrenheit).
Home heating is the fastest-growing means of exploiting geothermal energy, with global annual growth rate of 30% in 2005 (Lund et al.
The adjective geothermal originates from the Greek roots ?? (ge), meaning earth, and ?????? (thermos), meaning hot.
The Earth's geothermal resources are theoretically more than adequate to supply humanity's energy needs, but only a very small fraction may be profitably exploited.
Existing geothermal electric plants emit an average of 122 kilograms (270 lb) of CO2 per megawatt-hour (MW·h) of electricity, a small fraction of the emission intensity of conventional fossil fuel plants (Bertani and Thain 2002).
The are variants of these systems as well as hybrid systems that use different geothermal resources (USDOE 2012).
Geothermal provides a huge, reliable, renewable resource, unaffected by changing weather conditions.
Several entities, such as the National Renewable Energy Laboratory and Sandia National Laboratories, conduct research toward the goal of establishing a proven science around geothermal energy.
Flash steam power plants use hot water above 182°C (360°F) from geothermal reservoirs and has the addition of a flash tank over the dry steam design.
J. Donald Kroeker designed the first commercial geothermal heat pump to heat the Commonwealth Building (Portland, Oregon) and demonstrated it in 1946 (Kroeker and Chewning 1948).