What are the limitations of enegry that can be obtained from the oceans ?

Explanation

The forms of energy that can be obtained from the ocean are tidal energy, wave energy, and ocean thermal energy. There are several limitations in order to harness these energies.
`rarr` Tidal energy depends on the relative positioning of the Earth, moon, and the sun.
`rarr` High dams are required to be built to convert tidal energy into electricity.
`rarr` Very strong waves are required to obtain electricity from wave energy.
`rarr` To harness ocean thermal energy efficiently, the difference in the temperature of surface water (hot) and the water at depth (cold) must be `20^(@)C` or more.