Question

What is the energy from sea in the below options ?
A) Tidal energy
B) Wave energy
C) Ocean thermal energy
D) All of above

Answer 1

Hint: Tides are generated in the sea due to the gravitational pull of moon and sun.
Wave energy is generated due to the temperature gradient of earth present all over the ocean.
Ocean thermal energy is also obtained from sea due to the temperature gradient of ocean water.

Complete step by step answer:
Tidal energy- the regular rise and fall of the water level in the earth’s oceans as a result of the gravitational forces between the earth, moon and sun is called tides. The detailed theory involves the generation of the tides and harnessing this energy into useful applications.
The use of tidal energy, estimated at some \[4 \times {10^{18}}J\]per annum at known tidal sites.
Wave energy – wave energy is the capture of energy of wind waves to do useful work ( like for electricity generation, water desalination or pumping the water ).
A machine that exploits wave power is called a wave energy converter. Wave power is distinct from tidal power, which captures the energy of the current caused by gravitational pull of the sun and moon.
Ocean thermal energy – Ocean thermal energy conversion ( OTEC ) uses the ocean thermal gradient between cooler deep and warmer shallow or surface seawaters to run a heat engine and produce useful work, usually in the form of electricity.
OTEC can operate with a very high capacity factor and so can operate in base load mode.
Among ocean energy sources, OTEC is one of the continuously available renewable energy resources that could contribute to base-load power supply.
Since tidal energy, wave energy & ocean thermal energy all obtained from the ocean.
Hence option ( D ) is the correct option.

Note: Tides, waves and currents can be used to produce electricity. Although still at the research and development stages and yet not commercially available, promising ocean technologies include wave energy, tidal energy, salinity gradient energy and ocean thermal energy conversion.