Question

Why is there a need for harnessing non-conventional sources of energy? How can energy be harnessed from the sea indifferent ways?

Answer 1

Conventional sources of energy are limited. They are rapidly being used up and will be exhausted soon. Therefore, there is a need for harnessing non-conventional sources of energy.
Energy from Oceans: It is a potential source of renewable energy. There are many forms of ocean energy.
(1) Ocean Thermal Energy (OTE): There is always a temperature difference between water at the surface and at a deeper level up to ${20}^{o}C$. By exploiting this temperature difference one can harness energy. This form of energy is called ocean thermal energy which can be converted into electricity.
(2) Sea-Waves Energy: Energy from oceans is also available in form of sea waves. Due to the blowing of wind on the surface of the ocean. It has lot of kinetic energy due to high speed. It can be used to produce electricity.
(3) Tidal Energy : The rise of ocean water due to attraction of moon is called 'high tides' whereas fall of ocean water is called 'low tides'. The tidal waves rise and fall twice a day. The enormous movement of water between 'high tides' and 'low tides' provides a very large source of energy in the coastal areas of the world.
(4) Energy from Salinity Gradient in Seas : The concentration of salts in water of different seas is different. The difference in concentration of salts in the water of two different seas is called 'salinity gradient'. The difference is concentration of salts where water from different seas meet can be used to obtain energy in usable form.
(5) Energy for Sea-Vegetation or Biomass : Sea-Vegetation or biomass is another indirect source of energy from the oceans. For example, the vast amount of sea-weeds present in oceans may provide an endless supply of methane as fuel in future.