Water is used to generate electricity in three ways. Hydroelectric power is one of the most commonly used forms of renewable energy, accounting for around 7% of the world’s electricity production. Specially-built dams feed falling water into turbines that drive electricity generators. A similar system controls the flow of water in tidal areas, with a barrier built across an estuary or river. Wave power can also be harnessed by using floating generators that transform wave movement into electricity.
People have used moving water to help them in their work throughout history, and modern people make great use of moving water to produce electricity. No doubt, Jack the Caveman stuck some sturdy leaves on a pole and put it in a moving stream. The water would spin the pole that crushed grain to make their delicious, low-fat prehistoric bran muffins. For many centuries, water power was used to drive mills to grind grain into flour. People have used moving water to help them in their work throughout history, and modern people make great use of moving water to produce electricity.
Hydroelectric energy is produced by the force of falling water. The capacity to produce this energy is dependent on both the available flow and the height from which it falls. Building up behind a high dam, water accumulates potential energy. This is transformed into mechanical energy when the water rushes down the sluice and strikes the rotary blades of turbine. The turbine’s rotation spins electromagnets which generate current in stationary coils of wire. Finally, the current is put through a transformer where the voltage is increased for long distance transmission over power lines.
China has developed large hydroelectric facilities in the last decade and now leads the world in hydroelectricity usage. But, from north to south and from east to west, countries all over the world make use of hydroelectricity—the main ingredients are a large river and a drop in elevation (along with money, of course).
Although most energy in the United States is produced by fossil-fuel and nuclear power plants, hydroelectricity is still important to the Nation. Nowadays, huge power generators are placed inside dams. Water flowing through the dams spin turbine blades (made from metal instead of leaves). Power is produced and is sent to homes and businesses.
The theory is to build a dam on a large river that has a large drop in elevation (there are not many hydroelectric plants in Kansas or Florida). The dam stores lots of water behind it in the reservoir. Near the bottom of the dam wall there is the water intake. Gravity causes it to fall through the penstock inside the dam. At the end of the penstock there is a turbine propeller, which is turned by the moving water. The shaft from the turbine goes up into the generator, which produces the power. Power lines are connected to the generators that carry electricity to your home and mine. The water continues past the propeller through the tailrace into the river past the dam.
picture Credit : Google