Explain the two different ways of harnessing energy from the ocean.

Basically there are three ways of harnessing energy from the oceans and seas, but we are today going to discuss only two,

Which are :-

1. OCEAN THERMAL ENERGY :-

The water at the surface of the sea or ocean which, has considerable depth or deepness, is heated by the Sun while as we go deeper and deeper in the ocean or sea the upcoming sections become relatively colder than the previous one. This difference in temperature is used to obtain energy in ocean-thermal-energy conversion plants. These plants can operate if the temperature difference between the water at the surface and water at depths up to 2 km is 293 K (20°C) or more. The warm surface-water is used to boil a volatile liquid like ammonia. The vapours of the liquid are then used to run the turbine of generator. The cold water from the depth of the ocean is pumped up and condense vapour again to liquid.

2. OCEAN TIDAL ENERGY :-

Due to the gravitational pull of mainly the moon on the spinning earth, the level of water in the sea rises and falls. This phenomenon is called high and low tides and the difference in sea-levels gives us tidal energy by the same method as we saw in hydroelectric power plant , but in this method the gravitational energy by moon gives potential energy as well as kinetic energy to the water thereby there is formation of tides or waves. Tidal energy is harnessed by constructing a dam across a narrow opening to the sea. A turbine fixed at the opening of the dam converts tidal energy to electricity.

There is also Ocean wave energy.