Physics Report Geothermal

8/13/2019 Physics Report Geothermal

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GEOTHERMAL

ENERGY

MEANING OF GEOTHERMAL ENERGY

GEOTHERMAL ENERGY RESOURCES

USES OF GEOTHERMAL ENERGY

ADVANTAGES

DISADVANTAGES

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GEOTHERMAL ENERGY is thermal energy generated and stored in the

Earth. Thermal energy is energy that determines the temperature of

matter. Earth's geothermal energy originates from the original

formation of the planet, from radioactive decay of minerals, from

volcanic activity, and from solar energy absorbed at the surface.

The geothermal gradient, which is the difference in temperature

between the core of the planet and its surface, drives a continuous

conduction of thermal energy in the form of heat from the core to thesurface.

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Different Geothermal Energy Sources

Hot Water Reservoirs: As the name implies these arereservoirs of hot underground water. There is a largeamount of them in the US, but they are more suited forspace heating than for electricity production.

Natural Steam Reservoirs: In this case a hole duginto the ground can cause steam to come to thesurface. This type of resource is rare in the US.

Geo-pressured Reservoirs: In this type of reserve,brine completely saturated with natural gas in storedunder pressure from the weight of overlying rock. Thistype of resource can be used for both heat and fornatural gas.

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Normal Geothermal Gradient: At any place on theplanet, there is a normal temperature gradient of

+300

C per km dug into the earth. Therefore, if onedigs 20,000 feet the temperature will be about 1900Cabove the surface temperature. This difference will beenough to produce electricity. However, no useful andeconomical technology has been developed to

extracted this large source of energy. Hot Dry Rock: This type of condition exists in 5% of

the US. It is similar to Normal Geothermal Gradient,but the gradient is 400C/km dug underground.

Molten Magma: No technology exists to tap into theheat reserves stored in magma. The best sources forthis in the US are in Alaska and Hawaii.

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Uses of Geothermal Energy

GREENHOUSE

AGUACULTURE

INDUSTRIAL PROCESS

HEATER

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Many farmers use

geothermal power to heattheir greenhouses. InTuscany, Italy, farmers have

used water heated bygeothermal energy for

hundreds of years to growvegetables in thewinter. Hungary is also amajor user of geothermal

power. Eighty percent of the

energy demand fromvegetables growers is met byusing geothermal energy.

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Geothermal energy is

also used in fishingfarms. The warm water

spurs the growth ofanimals ranging fromalligators, shellfish,

tropical fish, amphibiansto catfish and trout. Fish

farmers from Oregon,Idaho, China, Japan, and

even Iceland usegeothermal power.

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Industry is anotherconsumer ofgeothermal

energy. Its uses

vary from dryingfruits, vegetables,wood, dying woolto extracting gold

and silver fromore.

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Geothermal energy

is also used to heat

sidewalks and roads

to prevent freezingin the winter.

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ADVANTAGES

Geothermal energy does not emit carbon dioxide. Geothermal energy is also very efficient, because after a site

is located and a geothermal power plant is built, the effortsrequired to channel it are negligible.

Moreover, there is no necessity of geothermal power plants to

be as large in sized as atomic power plants, huge dams, andelectrical plants, thus there is less impact on the environment.

Plus, it is an alternative source of energy, which means thatby using it we get less dependent on coal and oil.

Perhaps the most important advantage of geothermal energyis that, unlike energy derived from carbon-based sources,geothermal energy will never run out. And because it isubiquitous, its cost will never continue to rise with time.Hence, after the costs of the investigation to seek out thesource and building the power plant are recouped, in the end,geothermal energy will be very cheap.

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DISADVANTAGES

Location:Drilling a well into the earth, is a hard task. To make

this task economically viable, an ideal site for drilling a well in

order to trap geothermal energy, must provide hot rocks in the

layer of the Earth's crust that would heat the water pumped

into the well at suitable level. Next, it must be easy enough tobore a well to the hot rocks. This can be achieved, only if the

layer of rocks sitting above the hot rocks are easy to drill

through. The use of geothermal energy is hampered because

of the low number of suitable sites to drill a well. Critics of

geothermal energy say that such a project may only be usefulto provide electricity or heat to the local area only. In this

case, remoteness of the site may well negate its usefulness.

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DISADVANTAGES

Gases: Geothermal energy cannot be used without its hazards. Important

among the disadvantages of geothermal energy are the chances of

hazardous gases, like hydrogen sulfide coming to the surface of the Earth,

along with the hot water. Materials like arsenic, mercury, ammonia, which

may cause health hazards may also come up with the hot water. These

materials, which could cause environmental pollution, are not easy to dealwith.

Lifespan:As the sites, where you can obtain easy access to the hot rocks,

are located in areas of volcanoes, investors are not willing to invest in such

areas. Those sites in the fault areas will always be under the threat of

earthquakes. There are also chances of steam production not coming up to

the mark, which may make the project economically difficult to sustain. Themovements of the layers of the Earth or rock may cause the well to dry up,

which may lead to the closure of the electricity plant and financial losses.

This uncertainty over the lifespan of the project is big enough, to count it as

the biggest disadvantage of geothermal energy. Read more: geothermal

energy facts.

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Physics Report Geothermal