What is Geothermal Energy and How it is Produced
As its name refers geo thermal energy is the energy which is extracted from the heat of the sun thats is why it falls under the renewable energy. This energy is present into the earth due to the decay of minerals and absorption of sunlight by earth. Geothermal heat has innumerable applications form the ancient times it was earlier used for bathing and space heating. However, now this immense source of energy is used for producing electricity mostly. Geothermal energy is a reliable, cost effective and inexhaustible energy reservoir. Geothermal heating application was limited earlier near to the tectonic plates only. However, now this viable energy source is expanded over large geographical area.
Applications of Geothermal Energy
There are unlimited applications of geothermal energy. Some of them are electricity production, space heating, spas, industrial processes and agricultural application. Like all renewable energy sources geothermal heat can be also used to generate electric current. The capacity factor of geothermal energy to generate electric current is much more than the other alternative sources of energy like solar heat and wind power. This capacity is estimated to be 96%. USA possesses the largest geothermal power plant in the world which is located in California. Moreover geothermal heating is also used for direct heating functions as direct heating is considered most efficient because it puts less heating pressure on thee heating source. Geothermal electric energy can be extracted from the earth by installing heat exchangers into the earth. This geothermal energy can or cannot be used with electricity in order to support heating applications. The energy for the geothermal heat pumps can be pulled out by earth tubes and heat exchangers. The heat from the earth can be directly transferred to the radiators for heating homes.
Cost of Geothermal Power Plants
The capital cost of deploying geothermal power plants is high but it does not require any fuel in order to operate therefore it is cost effective once deployed. The drilling cost is significantly higher and so as the risk of correct location. The construction of an electric plant including the drilling costs is estimated to require an initial investment of 2 to 5 million pounds per MW. The cost of electricity production is higher but direct heating does not cost that much. The drilling cost associated with direct heating projects is also low because shallow wells are enough to fulfill the heating needs. District heating system has low capital cost because it is spread over the large geographical are but the cost of pipes and their installation will overtake this incentive.
The Sources of Geothermal Heat
Due to the conduction at 44.2 terawatts, the heat form the earth naturally flow to the upper layer of earth. It is further reloaded by the radio active decay of minerals at about 30 terawatts. These energy power rates are more than enough to meet the energy needs of entire population on earth. However the problem is that it is very difficult to recover them form depth of the earth. The geothermal energy is not only present in the depth of the earth resulting from the decay of minerals but it is also present in the upper surface of earth. The upper surface of the earth absorbs the large quantity of sunlight in the summer and then replenishes it back in winter. There are various ways to extract the geothermal energy from the earth like production well, injection well and heat exchangers. The internal temperature of earth is 3·1015 TW. This largely because of the deposits of plantery accretion in earth’s surface. These renewable enrgy sources can expire which would result in lower temperature and water levels.