Hydropower

Hydropower uses the motion of water (usually rivers, sometimes tides) to generate electricity.
This is a source of green energy that is only available in some parts of the world.[QUANTIFICATION needed]
Most hydro power plants that can be built, already have been - with some exceptions.
Considerations
Geography
Major limiting factor
This section has not been filled in yet. This section should also link to the page on new hydropower opportunities.
Effects on wildlife
[RESEARCH needed]
This section has not been filled in yet. Need to cover both aquatic life (fish etc) and surrounding landscape.
Displacement of people
[RESEARCH needed]
This section has not been filled in yet. Need to talk about the 1.4 million people who had to be relocated (homes demolished) in order to build the Three Gorges Dam in China. Is this a common occurrence for hydropower construction?