Where Is Hydropower Used In The Us?

Where is hydropower used in the US?

Hydropower is the process of using the energy from flowing water to generate electricity. According to the History of Hydropower, the first U.S. hydroelectric power plant opened on the Fox River near Appleton, Wisconsin in 1882. Since the late 19th century, hydropower has played an important role in the development of the United States. Today, hydropower is the country’s leading renewable energy source and provides around 7% of total electricity generation. With its low operating costs and ability to quickly adjust output, hydropower helps maintain reliable and affordable electricity supplies while supporting the increased use of intermittent renewable sources.

Hydropower is an essential part of the U.S. renewable energy portfolio and contributes to grid resilience and national energy security. The flexibility and storage capabilities provided by hydropower projects make this a valuable source of renewable electricity.

Hydropower Generation Capacity

The United States has over 100 gigawatts (GW) of installed hydropower capacity, making it one of the largest producers of hydroelectricity in the world. As of 2022, hydropower accounted for around 7% of total U.S. electricity generation and 44% of electricity generation from renewable sources.1

Hydropower capacity has increased modestly in recent decades through efficiency improvements and capacity additions at existing facilities. According to the U.S. Energy Information Administration (EIA), total U.S. hydropower capacity grew from 99 GW in 2010 to 101 GW in 2022.2 However, hydropower’s share of total U.S. electricity generation has declined from nearly 10% in 1995 as other renewable sources like wind and solar have expanded.

The top five states for installed hydropower capacity are Washington, California, Oregon, New York and Alabama. The Northwest and Southeast regions host the majority of large-scale hydropower facilities.3 Looking ahead, most growth in the hydropower sector is expected to come from efficiency upgrades at existing plants rather than major new projects.

Largest Hydropower Plants

The largest hydropower plants in the United States based on generating capacity are:

  1. Grand Coulee Dam – located on the Columbia River in central Washington state, it has a generating capacity of 6,809 MW (China’s top hydropower plants slash capacity amid heavy …).
  2. Chief Joseph Dam – located on the Columbia River on the border between Washington and Oregon, it has a generating capacity of 2,620 MW.
  3. Robert Moses Niagara – located on the Niagara River in Niagara Falls, New York, it has a generating capacity of 2,525 MW.
  4. John Day Dam – located on the Columbia River in north-central Oregon, it has a generating capacity of 2,160 MW.
  5. Hoover Dam – located on the Colorado River on the border between Nevada and Arizona, it has a generating capacity of 2,080 MW.

The massive size and generating capacities of these mega dams illustrate the vast potential of hydropower across the United States. Proper management and operation are crucial, however, to balance electricity production with environmental impacts.

Hydropower Dams & Reservoirs

There are over 2,300 hydroelectric dams in the United States, according to the U.S. Army Corps of Engineers[1]. Some of the major hydropower reservoir projects include the Grand Coulee Dam on the Columbia River in Washington State, which is one of the largest hydropower facilities in the U.S. with over 6,800 MW of generating capacity[2]. Other major projects include the Hoover Dam, which spans the Colorado River between Nevada and Arizona, providing over 2,000 MW of power[3]. In California, the significant hydropower facilities include Shasta Dam, Oroville Dam, and Folsom Dam among others. Overall, the western U.S. contains many of the major reservoirs and hydropower facilities in the country.

Hydropower Potential

The United States has significant remaining hydropower potential according to the Department of Energy’s Hydropower Vision report. Undeveloped U.S. hydropower resources, if fully realized, could provide nearly 50,000 megawatts of new hydropower capacity by 2050.

The most promising new sites for hydropower development are untapped streams and conduits, where small hydropower systems could be installed without the need for dams or diversions. Adding power generation equipment to existing non-powered dams also presents a major opportunity. According to the DOE’s Hydronext initiative, there is potential for over 12 gigawatts of new hydropower generation at existing non-powered dams around the country.

Environmental Impact

Hydropower can have both positive and negative effects on the environment. On the positive side, hydropower is a renewable energy source that produces no air pollution or greenhouse gas emissions. Hydroelectric dams can also help control flooding and provide recreational opportunities like fishing and boating. However, constructing large dams disrupts natural water flows and can harm local ecosystems and wildlife habitats. For example, dams block fish migration routes and change water temperatures downstream. The reservoirs created by dams also flood valleys and forests. When the flooded vegetation decomposes, it releases methane, a potent greenhouse gas. Some studies suggest certain hydropower reservoirs produce more emissions than equivalent natural gas power plants (Grist, 2022). Dams also change sediment flow in rivers, which alters downstream habitats. Overall, hydropower’s environmental effects are complex and site-specific. While renewable, hydropower still substantially alters local ecosystems and must be carefully managed to limit negative impacts (Erwin Record, 2022).

Hydropower Regulation

The main federal regulatory body for hydropower in the United States is the Federal Energy Regulatory Commission (FERC). FERC issues licenses and regulates non-federal hydropower projects under the Federal Power Act. According to FERC, “Hydropower regulation, the oldest area of the Commission’s jurisdiction, began with the passage of the Federal Water Power Act in 1920, which required the Commission to ensure that hydroelectric projects are constructed, maintained and operated in ways that protect or enhance fish and wildlife, water quality, recreation, and other environmental values” (https://www.ferc.gov/industries-data/hydropower).

Some key laws related to hydropower regulation include:

  • Federal Power Act – Gives FERC authority to license and regulate non-federal hydropower projects
  • Public Utility Regulatory Policies Act – Promotes energy conservation and renewable energy
  • Electric Consumers Protection Act – Amended the Federal Power Act to authorize FERC to issue licenses for longer terms
  • Energy Policy Act – Streamlined the hydropower licensing process

FERC issues licenses for terms between 30 and 50 years. The licensing process requires consultation with federal and state resource agencies and public input. FERC aims to balance power generation with minimizing impacts to environmental, recreational, and cultural resources.

Regional Use

The Pacific Northwest region, comprised of Washington, Oregon, Idaho, and Montana, generates the most hydropower in the U.S. According to the U.S. Energy Information Administration, this region accounted for over 30% of total U.S. hydroelectric generation in 20191. The region contains major dams like Grand Coulee in Washington state, which is the largest hydroelectric power producer in the U.S. Other top hydropower producing states include New York, California, and Alabama.

Some of the largest regional hydropower projects in the U.S. include:

  • Columbia River Basin – supplies around half of the electricity used in the Pacific Northwest
  • Colorado River Storage Project – provides power across Colorado, Utah, Wyoming, New Mexico, and Arizona
  • Robert Moses Niagara Power Plant – major producer for New York state

Many states are also pursuing new regional projects to expand renewable energy production. For example, the Boardman to Hemingway Transmission Line Project aims to facilitate renewable energy transmission across Idaho and Oregon.2

Future Outlook

The future of hydropower in the United States looks promising, with projections of growth and increased investment. According to the Department of Energy’s Hydropower Vision report, U.S. hydropower capacity could grow from 101 GW in 2015 to nearly 150 GW by 2050. This growth will be driven by powering existing dams that do not have electricity generation, new closed-loop pumped storage hydropower projects, and technological innovations.1

Major investments aimed at modernizing and improving hydropower infrastructure are expected. Upgrades to existing hydropower facilities could add up to 5 GW of capacity through 2030. There are also over 50 GW of new hydropower projects and additions in the development pipeline. Policy and regulatory reforms that improve hydropower’s value could further support growth and investment.1

Innovations in hydropower technologies, especially for small hydro, conduits, and marine hydrokinetic systems, can unlock additional generation potential. Investments in research and deployment of new technologies like adjustable-speed turbines, modular and scalable hydropower systems, and ocean wave and tidal devices will be important. Advances in data analytics, controls, materials, and manufacturing can also improve performance and lower costs.2


Hydropower is an important source of renewable electricity generation in the United States. The top hydropower producing states are Washington, California, and Oregon, which together account for over half of total US hydropower generation. While most major dams and reservoirs were built decades ago, hydropower remains the leading renewable electricity source in the US today.

Going forward, growth in hydropower capacity may be limited compared to other renewables like solar and wind. However, existing hydropower facilities provide reliable baseload power that complements intermittent renewable sources. Upgrades and optimizations at existing dams can also increase generation without building new dams. With the right policies and incentives, hydropower can continue providing clean, renewable electricity to meet national climate goals.

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