Electricity can also be produced by generators driven by water turbines that convert the energy in falling or fast-flowing water to mechanical energy. The advantages of hydroelectric power over such other sources as fossil fuels and nuclear energy 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.
Tidal-electric poweris obtained by utilizing the recurring rise and fall of coastal waters. Large amounts of electric power could be developed in the world's coastal regions having tides of sufficient range, although even if fully developed this would amount to only a small percentage of the world's potential water power.
The term geothermal energystands for power obtained by using heat from the Earth's interior. Most geothermal resources are in regions of active volcanism. Hot springs, geysers and pools of boiling mud are the most easily exploited sources. The ancient Romans used hot springs to heat baths and homes, and similar uses are still found in Iceland, Turkey, and Japan. Geothermal energy's greatest potential lies in the generation of electricity. It was first used to produce electric power in Italy in 1904. Today geothermal power plants are in operation in New Zealand, Japan, Iceland, Mexico, the U.S., and elsewhere.
Listening 3. Biofuel no answer to greening cars: report.