Limitations of energy that can be harnessed from the sea:

1. There are very few sites around the world which are suitable for building tidal barrage for harnessing tidal energy. Moreover, the rise and fall of sea-water during high and low tides is not enough to generate electricity on a large scale.

2. The harnessing of sea-waves energy is a viable proposition only at those places where sea-waves are very strong.

3. Though the energy potential from the sea is very large but its large scale exploitation is difficult at the moment.