Hydropower is the generation of electricity using the force of water. The usual mechanism involves damming a stream to produce head, then releasing water through a turbine which drives a generator. Placing a suitable turbine in flowing water can also be used to generate small amounts of electricity.
Hydropower is renewable energy which does not require consumption of fossil fuels. However, construction of large dams and storage of large amounts of water in reservoirs has profound environmental and social impacts, as illustrated by the Three Georges Project on the Yangtze River in China.
- "Chinese Dam Projects Criticized for Their Human Costs" article by Jim Yardley in The New York Times November 19, 2007