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Solar and Geothermal Energy: The Unconventional Way Ahead

Posted on April 10, 2011 in Environment


By Dubey Harshit R.P.:

The recent spate of unfortunate events in nuclear power industry in Japan have once gain brought into light loopholes associated with the safety factor of nuclear power where one minor error can trigger a huge catastrophe. We have already discussed it in the past that the way to go forward is unconventional energy resources but it`s high time we shifted our focus to solar and geothermal energy where the technical and economic aspects are major hindrance in its successful large-scale implementation today but their application will gain momentum after few years.

Solar energy can be briefly divided into solar thermal and solar photovoltaic and both adopt distinct technology to generate electricity. Solar thermal involves heating of water using a flat plate or a parabolic collector. This water can then be used to boil a liquid having low boiling point. The vapors then expand in a turbine and when synchronized with a generator electricity is generated. This concept is still cost ineffective for large-scale power generation and research is being carried out to improvise on concentration area of collector.

Solar photovoltaic directly generates electric current using semiconductors which convert incident solar radiation to electric current utilizing the concept of photoelectric effect. Maximum efficiency that can be attained using silicon as a semi-conductor is 26%. In metropolitan cities we see many newly built flyovers and bridges utilizing this concept for street lightning. 2000 MW of electricity has to be added to the grid using solar power by the end of phase I of Jawaharlal Nehru National Solar Mission.

Geothermal energy is one area which has been completely overlooked to meet India`s escalating energy demand. Geothermal means heat derived from the earth or the earth`s heat. At earth`s core temperature is around 5000°C which exponentially decreases as we reach the surface of earth but still below the earth`s crust i.e. 25-30 km deep there is magma (liquefied rock) which heats up the nearby water and rock. Some of this hot geothermal water reaches the earth surface through faults and cracks in the form of hot springs and geysers, a common phenomenon in New Zealand.

Geologists perform extensive testing and exploration to locate underground areas containing geothermal water and deep production wells are dug. The next step requires a power plant to be setup right on top of the natural reservoir. The steam or hot water then provides the force to spin the turbine generators and produce electricity.

Although this concept is still in a very nascent stage in India geothermal resources were used for the first time to generate electricity in early nineteenth century in Italy.

The following are some of its advantages:

Clean: Geothermal energy is completely pollution free and it provides the world a cushion to save fossil fuels for few more years.

Land constraints: Land constraints can be a major problem for acquisition of lands for solar power plants in the near future but for geothermal power this problem is very much minimized.

Reliability: Geothermal power plants run 24 hours a day resistant to interruption in power due to natural calamities or bad weather.

Price fluctuation: Oil prices keep fluctuating due to political instability or due to demand rise but for geothermal the resources will remain where they are in inexhaustible capacity so the input and operating cost can always be kept under control.

Roughly two-third of total power capacity in India is contributed by thermal power at a cost of Rs 4 crore per MW and a quarter by hydro power at a cost of Rs 6 crore per MW and solar power costs around Rs. 14 crore per MW. The renewable resources are still very much costly when compared to the non renewable ones but certain tax incentives and encouraging research work in renewable resources can make the future favorable for continual rise in India`s economic and social growth.