Most U.S. hydropower capacity is in the West
More than half of U.S. hydropower capacity1 for electricity generation is concentrated in Washington, California, and Oregon. Washington has the most hydroelectric generating capacity of any state and is the site of the Grand Coulee Dam, the largest hydropower facility in the United States. New York has the largest hydroelectric capacity of all states east of the Mississippi River, followed by Alabama.
Most hydropower is produced at large facilities built by the federal government. The West has many of the largest hydropower dams. Many smaller facilities also operate around the country.
The share of U.S. total hydropower generation capacity by the top five states in 2015:
- Washington—27%
- California—13%
- Oregon—11%
- New York—6%
- Alabama—4%
Because the amount of electricity generation from hydropower depends on precipitation, the ranking of each state in annual hydroelectricity generation may be different from its ranking in generation capacity.
The share of U.S. total hydropower generation by the top five states in 2015:
- Washington—38%
- Oregon—13%
- New York—11%
- California—6%
- Alabama—4%
Most dams were not built for electricity generation
Only a small percentage of dams in the United States produce electricity. Most dams were constructed for irrigation and flood control and do not have hydroelectricity generators. The U.S. Department of Energy (DOE) estimated that in 2012, non-powered dams in the United States had a total of 12,000 megawatts (MW) of potential hydropower capacity.
1Net summer capacity for conventional hydroelectric power; does not include pumped storage hydropower.