Hydropower, or hydroelectric power, is a significant source of renewable energy in the United States. Nearly every state utilizes conventional hydroelectric facilities, with a large concentration of these facilities located in the western United States. These impressive structures, often large dams built by the federal government, harness the power of water to generate electricity.
About half of the total utility-scale conventional hydroelectricity generation capacity in the U.S. is located within Washington, California, and Oregon. Washington State stands out with the largest capacity, hosting the Grand Coulee Dam, the biggest hydropower facility in the nation and also boasting the highest electricity generation capacity of any power plant in the US. Looking to the eastern side of the Mississippi River, New York and Alabama are the leading states in conventional hydropower capacity.
In 2023, the total conventional hydroelectricity net summer generation capacity across the United States reached approximately 80,090 megawatts (MW), equivalent to about 80 million kilowatts.
- The top five states contributing to this capacity in 2023 were:
- Washington: 27%
- California: 13%
- Oregon: 10%
- New York: 6%
- Alabama: 4%
The Role of Precipitation in Hydropower Generation
It’s important to understand that hydroelectricity generation is intrinsically linked to precipitation levels. As precipitation varies throughout the year and from year to year, a state’s ranking in annual hydroelectricity generation can differ from its generation capacity ranking. Essentially, the amount of water available directly impacts how much electricity can be produced.
In 2023, conventional hydroelectricity contributed about 6% of the total utility-scale electricity generation in the United States, amounting to roughly 240 billion kilowatthours (kWh).
- The top five states in terms of actual hydroelectricity generation in 2023 were:
- Washington: 25%
- California: 13%
- New York: 12%
- Oregon: 10%
- Alabama: 4%
Pumped-Storage Hydropower Explained
Beyond conventional hydropower, pumped-storage hydroelectricity plays a role in the US energy landscape. In 2023, the US had around 23,167 MW of pumped-storage hydroelectricity generation capacity spread across 18 states. California, Virginia, South Carolina, Michigan, and Georgia were the top five states, accounting for 61% of the total national capacity.
Pumped-storage systems function by pumping water to upper reservoirs during off-peak hours, using electricity, and then releasing this stored water to generate electricity during peak demand. Interestingly, these systems typically consume more electricity for pumping than they generate, resulting in a net negative annual electricity generation balance. They are primarily used for energy storage and grid stability.
Dams and Untapped Hydropower Potential
While dams are often associated with hydropower, it’s crucial to note that only a small fraction of dams in the United States are equipped for electricity generation. The primary purposes of most dams are irrigation and flood control. However, the U.S. Department of Energy has estimated a significant potential for hydropower capacity at non-powered dams, around 12,000 MW in 2012. This highlights an opportunity to further expand hydropower generation by retrofitting existing dams with hydroelectric generators.
In conclusion, hydropower is a vital renewable energy source in the US, predominantly located in the western states. While generation capacity is concentrated in specific regions, actual generation is influenced by precipitation. Pumped-storage offers energy storage solutions, and untapped potential exists in non-powered dams, suggesting future growth possibilities for hydropower in the nation.
