30-04-2013, 12:32 PM
Solar Energy The Renewable Energy For The Future
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Abstract:
The oil shocks of 1970s led to spiraling crude oil prices in the world market which prompted planners to view energy security as an issue of national strategic importance. Energy security has an important bearing on achieving national economic development goals and improving the quality of life of the people. World’s dependence on crude oil will continue for most part of the 21st century but the continued dependence on crude oil is loaded against it with inherent price volatility linked to finite global reserves. In addition, global warming, caused largely by greenhouse gas emissions from fossil fuel energy generating systems, is also a major concern. So, there is a need to develop alternate fuels like non-conventional sources, considering the aforesaid two concerns.
This paper describes about the solar energy, one of the non-conventional sources and different ways of using it to convert to electric energy.
Introduction:
As the power demand is going on increasing day-by-day, it is responsible for our engineers to make it available as per the demand. Many of the power generating plant are using non-renewable sources as their primary source. But these may become extinct at any time and before facing the situation we have to choose an alternative to avoid the power crisis. One of the best alternatives is choosing Non-conventional sources like Solar energy, Wind Energy, Tidal energy, Bio-mass energy etc as the primary sources for power generation in power stations.
What is solar energy?
Solar energy can be converted into other forms of energy, such as heat and electricity. In the 1830s, the British astronomer John Herschel used a solar thermal collector box (a device that absorbs sunlight to collect heat) to cook food during an expedition to Africa. Today, people use the sun's energy for lots of things.
How is solar energy collected?
Solar energy can be used to heat a fluid such as water in solar collector panels. Simple types use flat collector panels mounted on a south-facing roof or wall, each with transparent cover to admit sunlight. Water circulates through channels or pipes inside each panel. The inside is usually painted black, because black surfaces readily absorb heat. The water is heated, and then the hot water is pumped to a heat exchanger that extracts the heat for use within the house.
Photovoltaic Cell:
Photovoltaic is the direct conversion of light into electricity at the atomic level. Some materials exhibit a property known as the photoelectric effect that causes them to absorb photons of light and release electrons. When these free electrons are captured, an electric current results that can be used as electricity.
Working Principle:
Sunlight is composed of photons, or particles of solar energy. These photons contain various amounts of energy corresponding to the different wavelengths of the solar spectrum. When photons strike a photovoltaic cell, they may be reflected, pass right through, or be absorbed. Only the absorbed photons provide energy to generate electricity. When enough sunlight (energy) is absorbed by the material (a semiconductor), electrons are dislodged from the material's atoms. Special treatment of the material surface during manufacturing makes the front surface of the cell more receptive to free electrons, so the electrons naturally migrate to the surface.
Conclusion:
In the capital city of India, Delhi, citizens can face hours without electricity, but they are the lucky ones. In some parts of India it can be days. The basic weakness of the electric supply industry is non-viability of tariff. In 2001-02, the cost of supply was Rs.3.50 a unit while the realization was only Rs.2.40. Free or highly subsidized supply for agriculture and subsidies to domestic consumers have resulted in uneconomic charges for industrial consumers. This policy has driven many industries to depend more and more on self-generation. A second weakness of the Indian situation is under investment in transmission and distribution relative to generation. This is due to the lack of proper return in the investment of the power stations. This leads to the increase in price/unit and making the cost unreasonable for the common man.