What is Tidal Energy?
Tidal energy means energy that derives from the earth’s tides. Tidal energy, as its name suggests, is energy that harnesses the power of the tidal movements of water. By harnessing this tidal power, tidal energy can generate electricity.
Tidal energy is a form of kinetic energy. The word ‘kinetic’ comes from the Greek word for ‘movement’, indicating that tidal energy is all about generating energy from movement.
Tidal energy can be generated from the waves of the sea. However, it can also be generated from the tidal flow of rivers – one example of such a tidal power project can be found at the Thames Estuary which is situated in London in the United Kingdom.
The proposed 50 MW tidal energy power plant at Gulf of Kutch (Gujarat, India) will use the strong ocean tides for energy generation. According to estimates, India has the potential to generate around 8000 MW of power through Tidal energy.
Advantages of Tidal Energy.
1. Cleaner and safer form of energy generation. No polluting smokes or greenhouse such as CO2 gases are released into the atmosphere when tidal energy is harnessed (whereas burning fossil fuels, for example, does).
2. Simple and less complex procedures. Tidal energy is a natural form of energy which harnesses the power of the earth’s natural resources. No expensive mining or extraction equipment is needed to harness tidal energy – it can be harnessed in very simple ways if necessary (for instance with a basic water-mill).
3. You can count on the tides! We can always rely on the tides to keep moving, so tidal energy is a very reliable source of energy – unlike wind power, for instance, which is dependent on the vicissitudes of the weather. Countries like India have large coastlines making it suitable for Tidal energy.
4. Sustainable. As such, this is a sustainable energy source. Harnessing tidal energy does not deplete the tides. The tides cannot be ‘used up’. Hence, we can harness their kinetic energy without depleting them.
5. Self-dependence. Tidal power enables communities and nations to generate their own energy domestically from their own natural resources, without having to rely on energy supplies from other countries.
6. High energy density. Tidal energy is very energy-efficient – little energy is lost per unit as the kinetic energy of the tide is converted into electrical energy. It has what is known as a ‘high energy density’.
7. Energy for the future. The electrical energy generated by the tides can be stored for future use.
8. Impressive. Some cutting edge engineering skill and some amazing technology goes into the creation of tidal energy.
9. Versatile. Tidal power generators can be placed not only along the shore of the ocean but also along the lengths of rivers and in estuaries. Further, this type of energy brings us close to nature as it uses the natural motions of the tides.
10. Traditional: This is a historic form of energy, as early forms of tidal energy included water mills, which have been used for millennia to power machinery or grind corn.
Disadvantages of Tidal Energy.
1. Tied to one place. Unlike coal, oil or natural gas, tidal energy sources cannot be easily transported for long distances.
2. Startup costs. Though it is cheap to produce once tidal power generators are up and running, these generators cost a significant amount to install. setting up some types of energy equipment in tidal bodies of water can be costly.
3. Energy can be produced within short time periods. In the case of the sea, tides happen only twice every day. So, the tidal energy will only be generated in these two relatively short periods of time each day.
4. At risk from extreme weather events: Energy generation can get disrupted by extreme weather events. For example, freezing over of seas/rivers, or a freak storm can disrupt or cut off tidally generated electricity.
5. Danger to aquatic and water life. Installing tidal power plants can disrupt the habitats of plants, fish, water birds and water mammals.
6. Vulnerability to damage. Though waves are the source of tidal energy large waves can also, ironically, cause great damage to tidal power plants.
7. Not suitable everywhere. Tidal energy is only suitable for communities that live within easy reach of a tidal body of water. For example, it cannot be installed at the middle of plains or deserts. It can be installed only near the seas, oceans, and rivers.
8. Stopping water flow. Tidal barrages work like dams to block up the flow of water at the mouth of a river or along the shore. This can have adverse effects on a community’s water supply.
9. Disruptive to habitats: Some types of equipment used for harnessing tidal energy can damage or disrupt the habitats of important species.
Tidal energy is a clean, green, renewable and effecient way of generating energy for communities that live close to tidal bodies of water. For other communities, however, it is not a viable energy source.