Energy from the Sea

ENERGY FROM THE SEA:-

Tidal Energy:-

-The difference in sea-levels gives us tidal energy. 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.

-The locations where such dams can be built are limited.

Wave Energy:-

-Similarly, the kinetic energy possessed by huge waves near the seashore can be trapped in a similar manner to generate electricity.

-The waves are generated by strong winds blowing across the sea.

-Wave energy would be a viable proposition only where waves are very strong.

-A wide variety of devices have been developed to trap wave energy for rotation of turbine and production of electricity.

Ocean Thermal energy:-

-The water at the surface of the sea or ocean is heated by the Sun while the water in deeper sections is relatively cold.

-This difference in temperature is exploited 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 20 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.

-The energy potential from the sea (tidal energy, wave energy and ocean thermal energy) is quite large, but efficient commercial exploitation is difficult.