Hydroelectric power is electricity generated by hydropower. Hydropower is harnessed through the gravitational force of falling or flowing water. On a worldwide standpoint, it is the most widely used form of renewable energy, supplying 2998 TWh of hydroelectricity in 2006 and even mor today. Hydropower has been used for centuries by humans. The electricity is typically created when the water is passed over large mechanical turbines, the water pressure forces the turbines to turn, the mechanical energy created is then converted into electricity.
Advantages of Hydroelectricity
Hydroelectricity does not "use" water, all of the water is returned to its source of origin. Hydroelectric power can be created 24/7 indefinitely assuming that the body of water it is utilizing never runs dry. It is also another absolutely clean source of energy. The power plants, once in place, do not create any waste byproducts in their conversion. Dams constructed can also shut their gates and conserve the water for use when power is in higher demand.
Disadvantages of Hydroelectricity
Like all power plants, hydroelectric plants are very expensive to build, and must be built to a very high standard. The high cost means that plants must operate for a long time to become profitable. The creation of dams can also create flooding of land, which means natural envrionment and the natural habitat of animals, and even people, may be destroyed.
The building of dams for hydroelectric power can also cause a lot of water access problems. The creation of a dam in one location may mean that those down river no longer have control of water flow. This can create controversy in places where neighboring countries share a water supply.