The two different ways of harnessing energy from ocean are as follows
(i) Tidal energy The energy derived from rising and falling ocean tides is called tidal energy. The tidal energy can be harnessed by constructing a tidal barrage or tidal dam across a narrow opening to the sea.
(ii) Ocean thermal energy Solar energy stored in the oceans in the form of heat is known as ocean thermal energy. Temperature differences between the deep ocean water and upper level is used to produce ocean thermal energy. The process of harnessing the thermal energy of the sea is called ocean thermal energy conversion.
