A hydro station generates power by the controlled release of water from the reservoir of a dammed elipsis
produced from generators
driven by water turbines
that convert the energy in falling or fast-flowing water to mechanical energy
. Water at a higher elevation flows downward through large pipes or tunnels (penstocks). The falling water rotates turbines, which drive the generators, which convert the turbines' mechanical energy into electricity. The advantages of hydroelectric power
over such other sources as fossil fuels and nuclear fission are that it is continually renewable and produces no pollution. Norway, Sweden, Canada, and Switzerland rely heavily on hydroelectricity because they have industrialized areas close to mountainous regions with heavy rainfall. The U.S., Russia, China, India, and Brazil get a much smaller proportion of their electric power from hydroelectric generation. Seealso tidal power
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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.