Summary:
- Hydroelectric power, or hydropower, harnesses the energy of water moving down a stream.
- Hydropower is the most widely used form of renewable energy in the world.
- It provides almost one fifth of the world’s electricity.
- The energy of waves and tides can also be used to produce water power.
- To harness water power, a stream must be dammed.
- Narrow valleys are the best for dams.
- Water power does have problems.
- A large dam stops a stream's flow, which floods the land upstream.
- People may be displaced.