the three forms in which energy from oceans is made available for use are-

1) wave energy

2) tidal energy

3) thermal energy

OTEC- ocean thermal energy conversion plant.

Water present at the surface of sea is continuously being heated due to sunlight but, the water present in the deep sea level is quite cold because sunlight is unable to penetrate deep into the water. So this difference in the different levels of water in the sea can be utilised efficiently to create electricity. It is done in OTEC i.e. ocean thermal energy conversion plants.