Hydroelectricity is electricity that is made by the movement of water. It is usually made with dams that block a river to make a reservoir or collect water that is pumped there. When the water is "let go", the huge pressure behind the dam forces the water down pipes that lead to a turbine. This causes the turbine to turn, which turns a generator which makes electricity. This use of renewable energy produces less pollution than steam engines do. Some places such as Norway and Quebec get most of their electricity this way.
Hydroelectric power plants
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Advantages of hydroelectricity
Hydroelectricity can be made very quickly. This makes it useful for times when demand for electricity is high. Water that has been stored in a reservoir can be released (let go) when needed, so the energy can be made quickly. This controllability also makes hydroelectricity a good match for less controllable intermittent energy sources. When the wind is not blowing or the sun is not shining, hydroelectricity can be released.
Another advantage is that hydroelectricity cannot run out as long as there is a good water supply. Once the dam is built, the electricity costs very little, no waste or pollution is produced, and electricity can be generated whenever it is needed.
A few hydro turbines do not have a dam but instead use the current of the "run of the river". They produce less electricity and cannot store energy for later use.
Disadvantages of hydroelectricity
The building of large dams to hold water can damage the environment. In 1983, the Australian government stopped the Tasmanian state government from building a dam on the Gordon River in Tasmania after a huge public protest. The dam would have flooded the beautiful Franklin River. The Three Gorges Dam in China will be the world's largest hydroelectricity project. The dam has flooded a huge area, meaning that 1.2 million people have had to be moved. Scientists are concerned about many problems with the dam, such as pollution, silt, and the danger of the dam wall breaking.
The Three Gorges Dam in Central China is the world's largest power producing facility of any kind.
Museum Hydroelectric power plant ″Under the Town″ in Serbia, built in 1900.
Turbine row at El Nihuil II Power Station in Mendoza, Argentina
A micro-hydro facility in Vietnam
Pico hydroelectricity in Mondulkiri, Cambodia
Hydroelectricity for Kids. Kiddle Encyclopedia.