The electricity produced by harnessing the gravitational force of flowing water is called Hydroelectricity.
This gravitational force of water is used to rotate turbines which in turn rotates the magnets in the generator to generate electricity, also categorized as a renewable energy resource. It is one of the oldest, cheapest and simplest electricity generation technology.
Hydroelectricity is broadly classified into four categories – a conventional (dams), pumped-storage, run-of-the-river and offshore marine (tidal). Hydroelectricity is one of the three major sources of electricity in the world, the other two are by burning fossil fuels and nuclear fuels. As of today, it accounts for one-sixth of the world’s total electricity production.
Advantages of hydroelectric power
Safe and clean – Unlike other power sources like fossil fuels, nuclear and biomass hydroelectric energy is clean and green. No fuel is used or released in the air in these power plants hence they do not emit any greenhouse gases.
Renewable energy source – It is considered as renewable since it uses the earth’s water to generate electricity. Water is recycled back to the earth in its natural form without any contamination. It will never run out of supply due to the natural water cycle.
Cost effective – Despite huge building costs, hydroelectric power is a cost-competitive energy source because the maintenance and operation cost is very low.
Flexible source – It is a flexible source of electricity as these power plants can be scaled up and down quickly depending upon the energy demands. The startup time of hydro turbines is much less as compared to steam or gas turbines.
Other uses – As huge reservoirs are created by hydroelectric projects this water can also be used for irrigation and aquaculture purposes. The lake which is formed behind the dam can be used for recreational purposes such as water sports and leisure activities, making it a tourist attraction generating revenue.
Disadvantages of hydroelectricity
Very high capital costs – These power plants and dams are sometimes very expensive. The construction cost is very high.
Failure risks – The dams hold back a very large amount of water, natural disasters, sabotage, construction quality, can be catastrophic to downriver settlements and infrastructure, due to huge floods. Such failures can affect the power supply and the flora, fauna and can also cause large no. of casualties.
Ecosystem damage – Large reservoirs cause submersion of extensive areas upstream of the dams, sometimes destroy lowland and riverine valley forests and grasslands. Also, it can affect the surrounding aquatic ecosystem of the plant site. Fish, aquatic birds and animals can have a great impact on them.