Friday, 12 March 2010
Geothermal Energy:-Are a source of alternative energy clean and renewable, and high thermal energy of natural origin in the magma stored in the ground. It is estimated that more than 99% of the mass of the Earth is a rock temperatures exceed 1000 degrees Celsius.
Advantage of this thermal energy mainly in the generation of electricity. In some cases, used for heating when the temperature near the Earth's surface or on the image of hot spring,This renewable energy, in theory, could be enough to cover the world's need of energy for a period of 100000 years to come, however, converted into electrical energy is very expensive, even though the primary energy (raw material) free of charge and widely available but difficult to obtain.
Date human use of geothermal energy:-
Not available thermal energy directly in nature only in geothermal sources, and that makes it easy to exploit. It is estimated reserves of geothermal energy in the belt depth of 2000 meters below the surface about what produces 250 billion tons of coal energy, in theory could cover that amount of energy the world needs energy for a period of 100000 years to come.
Apportion the sources for obtaining geothermal energy into two categories: hot water, groundwater and hot rocks that are found in active volcanic areas or in the depths beneath the surface of the ground and can take advantage of geothermal water and Ackoralharp in generating electricity and heating water used for heating, in addition to use in many fields of industry, agriculture, the other, in many cases using geothermal energy to heat homes when the temperature near the surface or on the image of hot springs or when the temperature is low (about 65 C), where the cost of extraction and use of reasonable. In Iceland the spreading hot springs, and is used for heating purposes.
Advantages of this energy:-
1-As renewable energy, they are sources of energy that Atnvd at least for the generations to come.
2-Clean energy not harmful to the environment, and do not cause any pollution both in the extraction or in the transfer or use.
3-Available in very large quantities and in the vast majority of countries in the world.
4-Low cost of energy production after the initial costs for the production of the station (which can be expensive).
5-High yield of energy extracted.
Generating electricity using geothermal energy:-
There are three types of power plants using geothermal energy, as follows:-
1-Dry steam plants:-
The oldest and most widespread, the same method used in Italy in 1904. These stations use water from the naturally in the deep layers, which is located under the influence of pressure and temperature prohibitively high, Veetm extracted by drilling deep wells come out in the form of water vapor because of high temperature and because of pressure difference. This steam is moving in the pipes and then displays the turbines spin generators that produce electric power. Condensate water is pumped to the ground by another well called injection wells.
These stations are used in high pressure fluids underground where they are concentrated in the pot with a small hole leading to another container with a moderate pressure, when the movement of fluid from the first vessel to the second through hole evaporates because of the speed difference and the high pressure. Run steam turbine and in turn drives an electrical generator which produces electricity. The remaining condensate water is pumped to the ground through injection wells.
3-Service stations double:-
Use of these stations are underground fluids with high boiling point (about 200 C) is pumped to the top where the water is heated with a normal boiling point (100 C) in another pipe going through the hot side of the tube. The water evaporates, which have been heated due to the heat of the liquid in the tube the other. Drives the steam turbine electric generator and condenses again, it is attributable to the hot side of the tube, and moving this way in the rotation continues. The extracted water is pumped back to the earth through injection wells.
Disadvantages and constraints:-
Despite all the advantages of geothermal energy, which made them at the forefront of alternative energy sources for the future. However, there are some factors that are difficult to spread at least in the present time. Among the most important of these reasons the high cost of establishing power generation of electricity using geothermal energy. The reason is that the difficulty of drilling deep abyss and central temperature is very high.