Although hydropower generation accounts for only about 7 percent of overall U.S. electricity generation, the following states depend heavily on this source of energy: Idaho, Washington, Oregon, Maine, South Dakota, California, Montana, and New York.

Hydropower generation has remained relatively flat for years since most of the best locations for hydropower generation have already been developed. Some increases in hydropower generation can be made by optimizing capacity by adding additional turbines and increasing efficiency at existing facilities.

The amount of hydropower generation also depends on the quantity of water available. A drought can have a devastating effect on a region that depends on hydropower.