The problem of surface disposal may be avoided by reinjection of wastewaters or condensates back into the countryside through disposal wells. Steam condensate reinjection has few problems and is practiced in Italy and the United States. The much larger volumes of separated waste hot water (about 55 tons or 50 metric tons per megawatt-electric) from water-dominated fields present a more difficult reinjection situation. Silica and carbonate deposition may cause blockages in rock fissures if appropriate temperature, chemical, and hydrological regimes are not met at the disposal depth. In some cases, chemical processing of brines may be necessary before reinjection. Selective reinjection of water into the thermal system may help to retain aquifer pressures and to extract further heat from the rock. A successful water reinjection system has operated for several years at Ahuachapan, El Salvador.
[AKam3] -- J. Patrick Muffler, Thomas C. Hinrichs, A. J. Ellis, "Geothermal power", in AccessScience@McGraw-Hill, http://www.accessscience.com, DOI 10.1036/1097-8542.287600

Temperatures in the Earth in general increase with increasing depth, to 400–1800°F (200-1000°C) at the base of the Earth's crust and to perhaps 6300–8100°F (3500–4500°C) at the center of the Earth. Average conductive geothermal gradients to 6 mi (10 km; the depth of the deepest wells drilled to date) are shown in [[#287600FG0010|Fig. 1]] for representative heat-flow provinces of the United States. The heat that produces these gradients comes from two sources: flow of heat from the deep crust and mantle; and thermal energy generated in the upper crust by radioactive decay of isotopes of uranium, thorium, and potassium. The gradients of [[#287600FG0010|Fig. 1]] represent regions of different conductive heat flow from the mantle or deep crust. Some granitic rocks in the upper crust, however, have abnormally high contents of uranium and thorium and thus produce anomalously great amounts of thermal energy and enhanced flow of heat toward the Earth's surface. Consequently thermal gradients at shallow levels above these granitic plutons can be somewhat greater than shown on [[#287600FG0010|Fig. 1]]. See also: Earth, heat flow in




loadBinary.aspx?aID=3301&filename=287600FG0010.gif
Calculated average conductive temperature gradients in representative heat-flow provinces of the United...




[AKam3] -- J. Patrick Muffler, Thomas C. Hinrichs, A. J. Ellis, "Geothermal power", in AccessScience@McGraw-Hill, http://www.accessscience.com, DOI 10.1036/1097-8542.287600




http://www.reuters.com/article/GCA-GreenBusiness/idUSTRE5AM2BE20091123

LONDON (Reuters) - Solar energy costs will drop by half in 2009 while other low-carbon technology costs will see their pre-subsidy costs drop by 10-20 percent, renewable energy analysts said on Monday.
Prices for renewable energy equipment, including wind turbines and solar panels, fell this year, but they were offset by higher financing costs in the wake of the global economic slowdown, New Energy Finance said in a quarterly research note. [AKam3]
<span style="font-family: Tahoma,Verdana,Arial,sans-serif; white-space: normal;">[[code]] {{"Geothermal energy."DISCovering Science. Online Detroit: Gale, 2003. Student  Resource Center - Silver. Gale.
 BARRINGTON HIGH SCHOOL. 24 Nov. 2009}} [[code]] </span>
 Geothermal energy is obtained from hot rocks beneath the earth's surface. The  planet's core, which may generate temperatures as high as 8,132&deg;F
 (4,500&deg;C), heats its interior, whose temperature increases, on an average,  by about 33.8&deg;F (1&deg;C)
 for every 59 ft (18 m) nearer the core.  Some heat  is also generated in the mantle and crust as a result of the radioactive decay  of uranium and
 other elements. In some parts of the earth, rocks in excess of 212&deg;F (100&deg;C) are found  only a few miles beneath the surface. Water that comes
 into contact with the  rock will be heated above its boiling point. Under some conditions, the water  becomes super-heated, that is, is prevented from
 boiling even though its  temperature is greater than 212&deg;F (100&deg;C). Regions of this kind are  known as wet steam fields.
 In other situations the water is able to boil  normally, producing steam.
 These regions are known as dry steam fields.  [AKam3]

Humans have long been aware of geothermal energy.Geothermal Power

Hydrothermal.png
(Image retrieved from www.flickr.com/photos/hshdude/419507209)

Geothermal energy is energy generated by heat stored beneath the Earth's surface. (Geothermal energy is energy generated by heat stored beneath the Earth's surface.) [CRob3]

History of geothermal power:

Archaeological evidence shows that the first human use of geothermal resources in North America occurred more than 10,000 years ago with the settlement of Paleo-Indians at hot springs. (http://www1.eere.energy.gov/geothermal/history.html) [Cbre3]

The Romans, for example, used geothermal water to treat eye and skin disease and, at Pompeii, to heat buildings. (http://geothermal.marin.org/pwrheat.html#Q41864) [Smil3]



1852

The Geysers is developed into a spa called The Geysers Resort Hotel. Guests include J. Pierpont Morgan, Ulysses S. Grant, Theodore Roosevelt, and Mark (Twain.http://www1.eere.energy.gov/geothermal/history.html ) [Smil3]
1864
Homes and dwellings have been built near springs through the millennia to take advantage of the natural heat of these geothermal springs, but the construction of the Hot Lake Hotel near La Grande, Oregon, marks the first time that the energy from hot springs is used on a large scale. (http://www1.eere.energy.gov/geothermal/history.html) [Smil3]

1900
Hot springs water is piped to homes in Klamath Falls, Oregon. (http://www1.eere.energy.gov/geothermal/history.html) [Smil3]

1940

The first residential space heating in Nevada begins in the Moana area in Ren (http://www1.eere.energy.gov/geothermal/history.html) [Smil3]

1970

The Geothermal Resources Council is formed to encourage development of geothermal resources (worldwide.http://www1.eere.energy.gov/geothermal/history.html) [Smil3]

1972

The Geothermal Energy Association is formed. The association includes U.S. companies that develop geothermal resources worldwide for electrical power generation and direct-heat (uses.http://www1.eere.energy.gov/geothermal/history.html) [Smil3]

1973
The National Science Foundation becomes the lead agency for federal geothermal programs. (http://www1.eere.energy.gov/geothermal/history.html) [Smil3]

1977

The U.S. Department of Energy (DOE) is formed. (http://www1.eere.energy.gov/geothermal/history.html) [Smil3]
1980
TAD's Enterprises of Nevada pioneers the use of geothermal energy for the cooking, distilling, and drying processes associated with alcohol fuels production. UNOCAL builds the country's first flash plant, generating 10 MW at Brawley, California. (http://www1.eere.energy.gov/geothermal/history.html) [Smil3]

1987

Geothermal fluids are used in the first geothermal-enhanced heap leaching project for gold recovery, near Round Mountain, Nevada.(http://www1.eere.energy.gov/geothermal/history.html)[Smil3]

1991
The Bonneville Power Administration selects three sites in the Pacific Northwest for geothermal demonstration projects. (http://www1.eere.energy.gov/geothermal/history.html)[Smil3]

1992
Electrical generation begins at the 25-MW geothermal plant in the Puna field of Hawaii. (http://www1.eere.energy.gov/geothermal/history.html2000)[Smil3]
DOE initiates its GeoPowering the West program to encourage development of geothermal resources in the western U. S. An initial group of 21 partnerships with industry is funded to develop new technologies. (http://www1.eere.energy.gov/geothermal/history.html)[Smil3]

2003
2003 The Utah Geothermal Working Group is formed.
http://www1.eere.energy.gov/geothermal/history.html) [Smil3]

Geothermal power (from the Greek roots geo, meaning earth, and thermos, meaning heat) is power extracted from heat stored in the earth. This geothermal originates from the original formation of the planet, from radioactive decay of minerals, and from solar energy absorbed at the surface. [CRob3]



Geothermal energy is generally harnessed in areas of volcanic activity. The Pacific Ring is a prime spot for the harnessing of geothermal activity because it is an area where the tectonic processes are always taking place. The picture below shows the general location of the Ring of Fire (EIA kids site).

external image ring%20of%20fire.jpg


(http://images.google.com/imgres?imgurl=http://academic.evergreen.edu/g/grossmaz/geowells.jpeg&imgrefurl=http://academic.evergreen.edu/g/grossmaz/heidtken.html&usg=__L6w_DLOk43O2loCkvlvUsiWruHc=&h=383&w=575&sz=24&hl=en&start=3&um=1&tbnid=kbAlWKCGtv-jkM:&tbnh=89&tbnw=134&prev=/images%3Fq%3Dgeothermal%2Benergy%26hl%3Den%26sa%3DN%26um%3D1) [CRob3]

The ancient Romans used hot springs to heat their baths and homes. This “magic water” was also used for medicinal and cooking purposes.

Archeological evidence shows that the first human use of geothermal resources occurred more than 10,000 years ago in North America, with the settlement of Paleo-Indians around hot springs.
In fact hot springs seem to have been one of our earliest luxuries. Wherever in the world hot water came to the surface, we have used it for remedial bathing.
The first known commercial use of geothermal energy in the United States occurred in Hot Springs, Arkansas in 1830. Asa Thompson charged one dollar each for the use of three spring-fed baths.
A hotel in Oregon USA used geothermal energy from underground hot springs to heat rooms in 1864.
The first industrial use of geothermal energy began near Pisa, Italy in the late 19th century. Steam coming from natural vents (and from drilled holes) was used to extract boric acid from the hot pools that are now known as the Larderello fields.
It was not until the start of the 20th century that geothermal power was used to make electricity.
In 1904 Prince Piero Conti, owner of the Larderello fields, ended a long-standing dispute with the local electricity company and attached a generator to a natural-steam-driven engine. It was a small generator which only lit four light bulbs - but the first of its kind none the less!
This experiment led to the installation of the worlds first geothermal power plant, in 1911, with a capacity of 250 kilowatts. By 1975 the Larderello fields were capable of producing 405 megawatts of power.
It was the world's only industrial producer of geothermal electricity until 1958, when New Zealand built a plant in Wairakei.
The Geysers Resort Hotel, California, was the site of the first geothermal power plant in the United States. It was built in 1922 by John D. Grant, and was capable of generating enough electricity to light the entire resort. It ceased operation when cheaper power sources became available.
In 1960, Pacific Gas and Electric began operation of the first successful geothermal power plant in the United States at The Geysers.
The largest group of geothermal power plants in the world - 21 in total - are now located at The Geysers in California.
The original turbine installed at The Geysers, lasted for more than 30 years, and produced 11 Megawatts of power. The Geysers are currently owned by the Calpine corporation and the Northern California Power agency. It currently produces over 750 Megawatts of power.
The 1950's saw the production of the first "water source" heat pumps designed for residential applications. In the early 1960's the water source heat pump was introduced into commercial and institutional applications.
By the 1980's, early versions of the geothermal heat pumps (GHP) we use today evolved from the water source heat pump industry. GHP's are rapidly growing in popularity, and GHP technology continues to evolve to this day. (http://www.top-alternative-energy-sources.com/history-of-geothermal-energy.html) [CRob3]


How is geothermal power used?:


This is how it works: When groundwater seeps below the earth's surface near a dormant volcano, the water is heated by reservoirs of molten rock, usually at depths of up to 9,800 feet (3,000 m). Wells similar to those used to produce crude oil and natural gas are drilled to recover the water. Once captured, steam and hot water are separated. The steam is cleaned and sent to the power plant. The separated water is returned to the reservoir, helping to regenerate the steam source. ( http://www.chevron.com/deliveringenergy/geothermal/?gclid=CLbx6euKp50CFQjyDAodL2yN3Q) [Smil3]

It has been used for bathing since paleolithic times and for space heating since ancient roman times, but is now better known for generating electricity. Worldwide, geothermal plants have the capacity to generate about 10 gigawattsof electricity as of 2007, and in practice supply 0.3% of global electricity demand. An additional 28 gigawatts of direct geothermal heating capacity is installed for district heating, space heating, spas, industrial processes, desalination and agricultural applications (http://en.wikipedia.org/wiki/Geothermal_power) [CRob3]

Binary System
Binary System

(http://www.alternative-energy-news.info/technology/heating/)
[GGil3]

Water is injected deep into the earth where it absorbs heat from the surrounding rock. As the fluid returns to the surface, that heat is used to generate electricity. The fluid is then re-injected. The system forms a closed loop. It creates almost no emissions and is entirely renewable. It also occupies a smaller surface area than either solar or wind power. ( "Geothermal Future.(Editorial Desk)(Editorial)." The New York Times 158.54555 (Jan 14, 2009) Editorial Desk: A32(L). Global Issues In Context. Gale. BARRINGTON HIGH SCHOOL. 3 Nov. 2009
<http://find.galegroup.com/gic/start.do?prodId=GIC>
) [CRob3]


Hot water contained in the ground near a volcano, geyser or thermal source is piped to the surface by drilling to extract steam and produce electricity (http://images.google.com/imgres?imgurl=http://visual.merriam-webster.com/images/energy/geothermal-fossil-energy/production-electricity-from-geothermal-energy.jpg&imgrefurl=http://visual.merriam-webster.com/energy/geothermal-fossil-energy/production-electricity-from-geothermal-energy.php&usg=__BobVt9Gqnt1QVgfLNMJ6AmNX7OI=&h=384&w=550&sz=88&hl=en&start=1&um=1&tbnid=B-m4S5UGK0sA7M:&tbnh=93&tbnw=133&am p;prev=/images%3Fq%3Dgeothermal%2Benergy%26hl%3Den%26sa%3DN%26um%3D1) [CRob3]

Geothermal energy is captured by using the heat below the outer layer of the earth's crust. By pumping water below the surface at "hot spots" where the earth's crust is thinner, the water is turned into steam. The steam is used to turn turbines and generate electricity. Hot spots are found all over the world, they are a very efficient and clean resource for energy. (http://images.google.com/imgres?imgurl=http://www.greenhabitatdesign.com/Alternative%2520Energy%2520Geothermal.gif&imgrefurl=http://www.greenhabitatdesign.com/Alertnative_Energy.htm&usg=__scd1t8BURXgAWZM-IAH8KU_9SyE=&h=510&w=744&sz=39&hl=en&start=2&um=1&tbnid=NO1Elou_heV_IM:&tbnh=97&tbnw=141&prev=/images%3Fq%3Dgeothermal%2Benergy%26hl%3Den%26sa%3DN%26um%3D1) [CRob3]


Geothermal energy is produced by drilling a well into the ground where thermal activity is occuring. Once a well has been identified and a well head attached, the steam is separated from the water, the water is diverted through a turbine engine which turns a generator. Usually the water is injected back into the ground to resupply the geothermal source. The pictures below illustrate how the set-up of a geothermal site collecting energy looks like(EIA kids site) and (Geothermal Education Office).external image geoplant1.gifexternal image geowells.jpeg


Benefits of using geothermal power:

Geothermal energy is available 24 hours a day, 365 days a year. Geothermal power plants have average availabilities of 90% or higher, compared to about 75% for coal plants. (http://www1.eere.energy.gov/geothermal/faqs.html) [GGil3]
In addition to providing clean, renewable power, geothermal energy has significant environmental advantages. Geothermal emissions contain no chemical pollutants or waste — they consist mostly of water, which is reinjected underground.(http://www.chevron.com/deliveringenergy/geothermal/?gclid=CLbx6euKp50CFQjyDAodL2yN3Q) [Smil3]

Geothermal energy is a reliable source of power that reduces the need for imported fuels. It's also renewable because it is based on a practically limitless resource — natural heat within the earth. ( http://www.chevron.com/deliveringenergy/geothermal/?gclid=CLbx6euKp50CFQjyDAodL2yN3Q) [Smil3]

Geothermal power is cost effective, reliable, sustainable, and environmentally friendly, but has historically been limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating, opening a potential for widespread exploitation. Geothermal wells release greenhouse gases trapped deep within the earth, but these emissions are much lower per energy unit than those of conventional fossil fuels. As a result, geothermal power has the potential to help mitigateglobal warming if widely deployed in place of fossil fuels.(http://en.wikipedia.org/wiki/Geothermal_power) [CRob3]
Energy can be extracted without burning a fossil fuel such as coal, gas, or oil. Geothermal fields produce only about one-sixth of the carbon dioxide that a relatively clean natural-gas-fueled power plant produces, and very little if any, of the nitrous oxide or sulfur-bearing gases. Binary plants, which are closed cycle operations, release essentially no emissions. Geothermal energy is available 24 hours a day, 365 days a year. Geothermal power plants have average availabilities of 90% or higher, compared to about 75% for coal plants. (http://www1.eere.energy.gov/geothermal/faqs.html) [Cbre3]

There are abundant supplies. The total power potential of geothermal hot water systems in the U.S. alone has been estimated to be as much as 10 million megawatts, with a resource life of between 100 and 300 years. Systems using the natural heat gradient of the earth are virtually unlimited in power potential; cold water would naturally sink down to replace water heated by the earth, and the rising hot water would be used to run steam generators or water desalination plants. Brine from the processed salt water could be reinjected into the rocks to replenish geothermal fluid supplies depleted by the process. Geothermal plants can be operational in as little as two years, compared to five years for fossil fuel plants and 10 years for nuclear operations. (http://www.trivia-library.com/b/geothermal-energy-arguments-for-and-against.htm) [CRob3]

Former Secretary of the Interior Walter J. Hickel concluded that ". . . geothermal resources, by approximately 1985, can have a potentially enormous impact in supplying the nation's needs for energy and augmenting the supply of water in regions with insufficient natural water. . . The development of geothermal resources could substantially increase national energy self-sufficiency and provide a dramatic improvement in the U.S. balance of payments posture." (http://www.trivia-library.com/b/geothermal-energy-arguments-for-and-against.htm) [CRob3]


Geothermal energy creates less environmental pollution, is renewable and sustainable, avoids importing energy resources, benefits remote areas, adds to energy source diversity, creates less waste disposal and has a long life span. (http://images.google.com/imgres?imgurl=http://academic.evergreen.edu/g/grossmaz/geowells.jpeg&imgrefurl=http://academic.evergreen.edu/g/grossmaz/heidtken.html&usg=__L6w_DLOk43O2loCkvlvUsiWruHc=&h=383&w=575&sz=24&hl=en&start=3&um=1&tbnid=kbAlWKCGtv-jkM:&tbnh=89&tbnw=134&prev=/images%3Fq%3Dgeothermal%2Benergy%26hl%3Den%26sa%3DN%26um%3D1) [CRob3]


  • First, it's clean. Energy can be extracted without burning a fossil fuel such as coal, gas, or oil. Geothermal fields produce only about one-sixth of the carbon dioxide that a relatively clean natural-gas-fueled power plant produces, and very little if any, of the nitrous oxide or sulfur-bearing gases. Binary plants, which are closed cycle operations, release essentially no emissions.
  • Geothermal energy is available 24 hours a day, 365 days a year. Geothermal power plants have average availabilities of 90% or higher, compared to about 75% for coal plants.
  • Geothermal power is homegrown, reducing our dependence on foreign oil. (http://www1.eere.energy.gov/geothermal/faqs.html) [CRob3]



Disadvantages of using geothermal power:
So, we have established the main disadvantages of building a geothermal energy plant mainly lie in the exploration stage. During exploration, researchers will do a land survey (which may take several years to complete) and then post their findings to the company that contracted the survey. (http://www.clean-energy-ideas.com/articles/disadvantages_of_geothermal_energy.html) [Smil3]

The disadvantages of geothermal energy are the initial expense and the amount of land required. It can cost thousands to dig out the land and lay the pipes. This is one of the geothermal energy problems and why it is not widely used. Another of the disadvantages about geothermal energy is that it requires a fair sized piece of land to implement. (http://www.articlesbase.com/environment-articles/geothermal-energy-facts-geothermal-energy-pros-and-cons-397739.html) [GGil3]

Still, large-scale commercial production is at least a decade away and will require improvements on currently available technology. Geothermal development also will mean still more competition for scarce water, more holes in the ground and more roads to service those holes. ("Geothermal Future." The New York Times 158.54555 (Jan 14, 2009) Editorial Desk: A32(L). Global Issues In Context. Gale. BARRINGTON HIGH SCHOOL. 24 Nov. 2009
<http://find.galegroup.com/gic/start.do?prodId=GIC>)
[CRob3]

Another big disadvantage of geothermal energy extraction, is that in many cases, a site that has happily been extracting steam and turning it into power for many years, may suddenly stop producing steam. This can happen and last for around 10 years in some cases. (http://www.clean-energy-ideas.com/articles/disadvantages_of_geothermal_energy.html) [CRob3]

Another big disadvantage of geothermal energy extraction, is that in many cases, a site that has happily been extracting steam and turning it into power for many years, may suddenly stop producing steam. This can happen and last for around 10 years in some cases. (http://www.clean-energy-ideas.com/articles/disadvantages_of_geothermal_energy.html) [GGil3]

Economic costs of using geothermal power:

The main costs associated with geothermal power and energy is labor, as for the average geothermal project, hundreds of meters of piping needs to be laid in order to achieve the desired output. (http://www.clean-energy-ideas.com/articles/cost_of_geothermal_energy.html) [cbre3] For every dollar invested in geothermal energy, the resulting growth of output to the U.S. economy is $2.50. This means that a geothermal investment of $400 million would result in a growth of output of $1 billion for the entire U.S. economy. (http://www.geo-energy.org/aboutGE/economicBenefits.asp#ec) [Smil3]

Costs of a geothermal plant are heavily weighted toward early expenses, rather than fuel to keep them running. Well drilling and pipeline construction occur first, followed by resource analysis of the drilling information. Next is design of the actual plant. Power plant construction is usually completed concurrent with final field development. The initial cost for the field and power plant is around $2500 per installed kW in the U.S., probably $3000 to $5000/kWe for a small (<1Mwe) power plant. Operating and maintenance costs range from $0.01 to $0.03 per kWh. Most geothermal power plants can run at greater than 90% availability (i.e., producing more than 90% of the time), but running at 97% or 98% can increase maintenance costs. Higher-priced electricity justifies running the plant 98% of the time because the resulting higher maintenance costs are recovered. (http://www1.eere.energy.gov/geothermal/faqs.html) [GGil3]

Unlike coal and natural gas, geothermal incurs no “hidden costs” such as land degradation, high air emissions, forced extinction and destruction of animals and plants, and health impacts to humans.(http://www.geo-energy.org/aboutGE/economicBenefits.asp) [GGil3]


When geothermal heat is close to the surface, it is cheap to tap: existing geothermal electricity, on average, is as cheap as wind energy. Most near-surfacegeothermal opportunities, however, have already been developed. Deeper resources, like those being developed in Australia, are more expensive because technical difficulty increases quickly with depth: the cost of a hole 6,500 feet (about 2,000 meters) deep is more than double that of a hole 3,250 feet (about 1,000 meters) deep, and a hole 9 miles (about 15 kilometers) deep cannot be drilled at all. (Eccleston, Roy. "Deep Heat.(Global Business; Energy)." Time International (South Pacific Edition) 26 (July 7, 2008) 55. Global Issues In Context. Gale. BARRINGTON HIGH SCHOOL. 3 Nov. 2009
<http://find.galegroup.com/gic/start.do?prodId=GIC>.) [CRob3]

At The Geysers, power is sold at $0.03 to $0.035 per kWh. A power plant built todaywould probably require about $0.05 per kWh. Some plants can charge more during peak demand periods. (http://www1.eere.energy.gov/geothermal/faqs.html) [cbre3]



At The Geysers, power is sold at $0.03 to $0.035 per kWh. A power plant built today would probably require about $0.05 per kWh. Some plants can charge more during peak demand periods. (http://www1.eere.energy.gov/geothermal/faqs.html) [CRob3]


Environmental impact of using geothermal power (Both +/-):


Geothermal power plants do not burn fuel to generate electricity, so their emission levels are very low. They release less than 1% of the carbon dioxide emissions of a fossil fuel plant. Geothermal plants use scrubber systems to clean the air of hydrogen sulfide that is naturally found in the steam and hot water. (http://tonto.eia.doe.gov/kids/energy.cfm?page=geothermal_home-basics) [Cbre3]
Geothermal plants emit 97% less acid rain-causing sulfur compounds than are emitted by fossil fuel plants. After the steam and water from a geothermal reservoir have been used, they are injected back into the Earth. (http://tonto.eia.doe.gov/kids/energy.cfm?page=geothermal_home-basics) [Cbre3]
Closed-loop systems are almost totally benign, since gases or fluids removed from the well are not exposed to the atmosphere and are usually injected back into the ground after giving up their heat. Although this technology is more expensive than conventional open-loop systems, in some cases it may reduce scrubber and solid waste disposal costs enough to provide a significant economic advantage.
Open-loop systems, on the other hand, can generate large amounts of solid wastes as well as noxious fumes. Metals, minerals, and gases leach out into the geothermal steam or hot water as it passes through the rocks. The large amounts of chemicals released when geothermal fields are tapped for commercial production can be hazardous or objectionable to people living and working nearby. (http://www.ucsusa.org/clean_energy/technology_and_impacts/impacts/environmental-impacts-of.html) [Cbre3]
At hydrothermal plants carbon dioxide is expected to make up about 10 percent of the gases trapped in geopressured brines. For each kilowatt-hour of electricity generated, however, the amount of carbon dioxide emitted is still only about 5 percent of the amount emitted by a coal- or oil-fired power plant. (http://www.ucsusa.org/clean_energy/technology_and_impacts/impacts/environmental-impacts-of.html) [Cbre3]
Salts and dissolved minerals contained in geothermal fluids are usually reinjected with excess water back into the reservoir at a depth well below groundwater aquifers. This recycles the geothermal water and replenishes the reservoir.(http://www1.eere.energy.gov/geothermal/faqs.html) [Cbre3]
  • Some geothermal plants do produce some solid materials, or sludges, that require disposal in approved sites. Some of these solids are now being extracted for sale (zinc, silica, and sulfur, for example), making the resource even more valuable and environmentally friendly. (http://www1.eere.energy.gov/geothermal/faqs.html) [Cbre3]


  • missions are low. Only excess steam is emitted by geothermal flash plants. No air emissions or liquids are discharged by binary geothermal plants, which are projected to become the dominant technology in the near future.
  • Salts and dissolved minerals contained in geothermal fluids are usually reinjected with excess water back into the reservoir at a depth well below groundwater aquifers. This recycles the geothermal water and replenishes the reservoir. The City of Santa Rosa, California, pipes the city's treated wastewater up to The Geysers power plants to be used for reinjection fluid. This system will prolong the life of the reservoir as it recycles the treated wastewater.
  • Some geothermal plants do produce some solid materials, or sludges, that require disposal in approved sites. Some of these solids are now being extracted for sale (zinc, silica, and sulfur, for example), making the resource even more valuable and environmentally friendly (http://www1.eere.energy.gov/geothermal/faqs.html) [CRob3]
Emissions are low. Only excess steam is emitted by geothermal flash plants. No air emissions or liquids are discharged by binary geothermal plants, which are projected to become the dominant technology in the near future.(http://www1.eere.energy.gov/geothermal/faqs.html) [GGil3]

Is there be any opposition to the use of geothermal power? Why? Do you agree or disagree with those views?:

The fear that energy development will rob the town of its precious supply of hot, mineral-rich water has propelled them to the forefront of the anti-geothermal movement. (http://peakenergy.blogspot.com/2009/02/japanese-getting-heated-over-geothermal.html) [CRob3]

The development of geothermal reservoirs is often unfeasible because they are too far from major population centers. Geothermal power plants release many pollutants (from processing mineral-laden steam and water), including the dangerous and malodorous gaseous forms of ammonia, hydrogen sulfate, and methane. They also release almost twice as much heat into the atmosphere as nuclear plants and are quite noisy. They are not at all foolproof; well blowouts have been known to rage out of control for days. The pumping or reinjection of thermal fluids may cause earthquakes. Lastly, geothermal drilling is expensive, costing two to three times as much as oil drilling, and present technology limits bore hole depths to 30,000 ft. (http://www.trivia-library.com/b/geothermal-energy-arguments-for-and-against.htm) [CRob3]

Would there be any societal impacts to the use of geothermal power?

Unlike solar panels, geothermal systems typically do not impact the appearance of a home. By definition, the systems involve the placement of piles or coils five feet under ground. Since they rarely have to be dug up, landscaping can be placed over the coils and no one is the wiser. (http://www.heatpumpprices.org/disadvantages-of-geothermal-energy-pros-and-cons) [GGil3]