Question 26: Why is there a need for harnessing non-conventional sources of energy? How can energy be harnessed from the sea in different ways?
Answer:
Non-conventional resources are the renewable process of energy which is continuously replenished (refill or freshen up again) by the natural resources. Electricity or energy generated by the wind by windmills, biomass, solar energy; all are the examples of non- conventional resources. Two main reasons for the need to harness non- conventional sources of energy are following:-
1. Exhaustible resources like fossil fuels take millions of years to form and decrease in these resources in future lead to the shortage for the future generation which in turn has serious repercussions on the growth of the natural economy; but non-conventional resources like wind, solar energy can be used continuously. Thus non-conventional resources need to be harnessed for future use.
2. Exhaustible resources pollute the environment when they are being used while non-conventional did not produce any harmful effect on the environment. They are pollution free, renewable, environment friendly so they are the best choice.
There are mainly three different ways of harnessing energy from ocean:- Tidal energy, wave energy and Ocean thermal energy and these are following:-
1. Tidal Energy:- The level of water in the sea rises and falls by the gravitational pull of mainly the moon on spinning earth, and this is called high and the low tides. And the difference in between the high and low tides is known as tidal energy. This energy is harnessed by constructing a dam across the narrow opening to sea and a turbine is fixed which converts tidal energy to electricity.
2. Wave Energy:- Kinetic energy possessed by large waves near the sea and used to generate electricity. And, these waves are generated by the strong winds. Wave energy can be trapped only where waves are very strong. Various devices have been used to trap wave energy for turning the turbine and production of electricity.
3. Ocean Thermal Energy:- Water at the surface of the sea is heated by sunlight but the deeper water is cold in sea. This energy is obtained from the temperature difference in ocean thermal energy conversion plants. The warm surface of water is used to boil the volatile liquid and then these vapours of liquid like ammonia. These vapours are then used to run the turbine of a generator. And, the cold water from the deeper section of the sea or ocean pumped and condenses vapours again into liquid.
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