RENEWABLE SOURCES OF ENERGY
Oceans are major source of energy. From oceans following types of energies can be obtained.
- Tidal energy
- Sea waves energy and
- Ocean thermal energy
Tidal energy may be defined as the energy possessed by water during high tides and low tides. The tidal energy of oceans can be used to produce electricity (tidal power). For this, usually a dam is constructed across river estuaries. During high tide, the water moves in the reservoir through small openings and rotates the turbines fixed inside them and thus produces electricity. The passed in water is collected in the reservoir by closing the gates of the openings. And during low tide the gates of openings are opened and the water collected in the reservoir is allowed to flow out into the sea in a controlled manner. This reverse flow of water through the openings again rotates the turbines and produces electricity.
Although tidal energy is also a non-polluting and renewable source of energy, it cannot be considered a reliable source. The reason for this is that tidal energy plants are suitable only at those places where the difference between high and low tide is 6m or more. Thus there are very few sites in the world which are suitable to construct tidal power plants. Also construction of tidal power plants across river estuaries may cause ecological imbalance by changing tidal levels.
Test Your Understanding and Answer These Questions:
- What is tidal energy?
- How tidal power plant works?