Geothermal Energy Sources

Hot Spring

Geothermal energy is clean and sustainable source of energy. Heat obtained from the earths crust can be used in many ways, from large power station to relatively small pumping system.Resources of geothermal energy is found in shallow ground to hot water and hot rock found few miles beneath the earth.
The energy present in the earth's crust which is in the form of heat such energy is called geothermal energy.
The uppermost crust up to 10 km or so of the earth's crust constitutes a potentially useful and almost inexhaustible source of energy.

Heat Extraction

In the above  representation of geothermal energy, at depth of 5-10 km or so lies impermeable magma and the magma are impermeable crystalline rocks which are overloaded by pockets of permeable rock . This localized pockets are founded by the fracture zone or faults around which some relative motion of rock has occurred.
Water is circulated along with the fault lines and moves in the earth's interior path. It is heated by permeable rock or layer which is in term heated by conduction of heat from the magma. The hot water comes out through another fault and forms a hot spring.
Availability of Geothermal Energy:-

Depending on the temperature and depth of the the permeable rock the natural hydro thermal systems can be divided into three categories:

1. Dry Steam System:- The temperature of permeable rock is very high. The whole of the water is converted into steam which is converted into steam which gets superheated by the time comes out on surface.
2. Wet Steam System:- The temperature of permeable rock is not very high.By the time water comes out on the surface only a part of it is get converted into steam therefore the eruption gives a water-steam mixture. 
3. Hot water System:- The temperature of permeable rock is rather low, therefore the surface eruption provides hot water. 

Vapour Turbine Cycle

Vapour Turbine Cycle

Recently in Geothermal plants heat exchanger and vapour turbine cycle have been proposed for generation. The geothermal hot water is used to heat for low boiling point fluids (Propane/Freon). This fluid expands in turbine which drives the generator. The fluid is condensed and reused to form a closed circuit system in vapour turbine cycle system. The low enthalpy geothermal water can also be profitably used.
It should be noted that electricity generated by California based Geothermal Power Plants(USA) is almost half of electricity generated by Geothermal Power Plants.

Geothermal Electricity Plant - California (USA)

Geothermal energy is also used for heating purposes.There are many examples of direct using of geothermal energy for heating purposes as for drying out fish, to heat greenhouses, for improving oil recovery, fish farms, etc. Around the world, people also used hot spring for relaxation and rest.

Advantages:

Geothermal energy has many advantages as follow:

1. Reliability:- Unlike other Non Conventional energy sources such as Wind, Tidal and Solar, Geothermal energy is reliable as it provides constant power.
2. Geothermal energy is environment-friendly. There is a very less or we can say no pollution is produced by Geothermal Plant. Although fumes are not produced while drilling the earth. Therefore there is no adverse effect on environment.
3. The pollution can be reduced somewhat by increasing use of Geothermal as well as other non conventional energy sources which is caused by use of many conventional fuels like oil, coal, etc.
4. Geothermal energy has many application. For instance it can be used to generate electricity as well as for providing heat to home and businesses. 

Types of Energy

Energy is the key input to drive and improve the life cycle. It's a gift of the nature to the mankind in various forms. The consumption of energy directly proportional to the progress and modernization of mankind. The continuous increase of population, improvement in standard for living, industrialization and the increase in demand of energy is expected to be more in near future. It is believed that at this rate of using fossil fuels, coal, natural gas, etc. there will be no energy at all.

There are two types of Energy:-

• Conventional Energy 

• Non Conventional Energy

Conventional Energy Sources

Conventional energy sources

• Oil - 40 %        

• Natural Gas - 22.5 %

• Coal - 23.3 %                 

• Hydroelectric - 7.0 %

• Nuclear - 6.5 %

• Biomass & others - 0.7 %

Non Conventional Energy Sources

Non Conventional Energy Sources

Fossil fuels supply most of the energy consumed today. They are relatively concentrated and pure energy sources, technically easy to exploit, and provide cheap energy. Presently

Conventional Energy from coal, natural gas and petroleum, hydel power are used abundantly at present. Except hydel power, the sources of thermal power i.e. other conventional energies are non renewable in nature. But the sources of non-conventional energy are flow-resources. There is no anxiety for their exhaustion. However the reserves of fossil fuels are limited.

To meet the future energy demands and to give quality and pollution free supply to growing and today's environment conscious population, the present world attention is to go in for natural, clean and renewable energy sources. These energy sources capture their energy from on going natural processes, such as geothermal, solar, wind, flowing water and biological process. 

Most form of energy, other than geothermal and tidal power ultimately come from the Sun. Some forms of energy such as rainfall and wind power are considered short term energy storage. Renewable energy is energy from a source that is replaced rapidly by a natural process and is not subjected to depletion in a human timescale.

Note:- The figures provided above about of Oil, Coal, etc may vary to date. As dependent on various websites, articles, books, the existence or capacity/storage of aforementioned sources of energy maybe different.