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A hydroelectric plant is a type of power plant that uses gravitational forces on water to create electricity. Hydroelectric plants have become popular in recent years, thanks to the growing demand for renewable and low-pollution energy sources. According to some statistics, hydroelectric plants produced about one-fifth of the world's energy in the first decade of the 21st century.
A hydroelectric plant works similarly to some coal plants. In a coal plant, steam is forced through a turbine, causing a the turbine to spin and activating an electricity generator. Unfortunately, coal is a quickly dwindling resource that produces high levels of pollution that contribute to poor air quality and global warming. A hydroelectric plant works the same way, but uses flowing water to spin the turbines.
The trick with a hydroelectric plant is how to get water to flow through the turbines. This is solved by placing the plant downhill of a water source, sometimes natural but often dammed. Rather than using energy to push the water down through the turbines, the natural force of gravity makes the water run downhill, pushing the turbines and eventually draining into a reservoir below the plant. When power demand is low, such as during late night hours, the plant diverts its energy to pulling the water back uphill in order to reuse it.
There are several countries in the world that have enthusiastically adopted this type of power as a renewable solution to growing electricity needs. China leads the world in hydroelectric power, though Canada, Brazil, the United States, and Russia are not far behind. Experts suggest that the increased acceptance of hydroelectric power as a major electricity source shows a growing movement toward sustainable and renewable sources. While undoubtedly less polluting than many alternatives, a hydroelectric plant still creates many environmental concerns.
Although many environmentalists believe alternative sources like hydroelectricity are preferable to high-polluting coal, oil, and natural gas, there are some environmental problems with the creation and use of a hydroelectric plant. The construction of dams and plants along natural water sources can disrupt migratory patterns of local fish populations. Water temperature can also change vastly during power production, upsetting the natural ecosystem of the river downstream of the plant.
Dam failure is a major consideration with a hydroelectric plant. Since larger plants often involve massive dams, breakage or failure can lead to serious consequences. Massive floods from hydroelectric dam failure have occurred, including the Banqiao failure in 2006, which resulted in the deaths of more than 20,000 people. Additionally, if a region is primarily supported by a dam that fails, power outages can delay rescue operations and render an area powerless for extended periods of time.