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Hydropower remains one of the major renewable energy sources in the United States. Recent data shows hydropower contributes nearly six percent of total U.S. utility-scale electricity generation and 27 percent of total U.S. utility-scale renewable electricity. Driven by massive dam infrastructure, key projects such as Grand Coulee and Bath County continue to shape America’s energy landscape. These hydropower projects generate electricity and support flood control, irrigation, and water storage. Many of the largest hydropower plants are situated along river systems in the Pacific Northwest and the Southeast, where hydropower potential is maximum. Together, they demonstrate the engineering excellence and long-term sustainability of U.S. hydropower.
Top 20 Largest Hydro Plants Ranked by Installed Capacity
Washington, Oregon, and California host the largest number of hydropower plants in the United States. Major river systems such as the Columbia, Snake, and Tennessee provide the ideal conditions and infrastructure for large-scale hydroelectric generation.
According to the U.S. Department of Energy’s 2023 Hydropower Market Report and the U.S. Energy Information Administration, the list below highlights the top 20 hydro plants based on the installed capacity:
Rank | Plant Name | State(s) | Installed Capacity (MW) | Approx. Annual Generation (GWh) | Notable Features |
1 | Grand Coulee Dam | Washington | ~6,809 MW | ~21,000 GWh | Largest hydro plant in U.S.; multi-purpose (power, irrigation, flood control) |
2 | Bath County Pumped Storage Station | Virginia | 3,003 MW | ~3,786 GWh | One of the largest “hydro” plants by capacity acts like a giant battery |
3 | Robert Moses Niagara | New York | 2,525 MW | ~15,896 GWh (average) | Diverts water around Niagara Falls; high capacity factor |
4 | Chief Joseph Dam | Washington | ~2,620 MW | ~11,239 GWh | Large flows, minimal reservoir control, sensitive to river conditions |
5 | John Day Dam | Oregon/Washington | ~2,485 MW | ~8,418 GWh | Major Columbia River project |
6 | Ludington Pumped Storage | Michigan | ~2,172 MW | -752 GWh | Acts as energy storage; reversible turbines |
7 | Hoover Dam | Nevada / Arizona | ~2,080 MW | ~3,542 GWh | Iconic multipurpose project (water supply, flood control, recreation) |
8 | The Dalles Dam | Oregon/Washington | ~1,878 MW | ~7,161 GWh | On the Columbia River: fish and navigation considerations |
9 | Raccoon Mountain Pumped Storage | Tennessee | ~1,652 MW | 2,272 GWh | Used for regional peaking flexibility |
10 | Castaic / Elderberry (part of California’s pumped storage) | California | ~1,500 MW (Castaic) | ~880.7 GWh | One of the largest pumped storage systems in California’s system |
11 | Helms Pumped Storage | California | ~1,212 MW | ~645.8 GWh | Supports the grid in California |
12 | Wanapum Dam | Washington | ~1,185 MW | ~5,338 GWh | Mid-Columbia reservoir project |
13 | Bad Creek Pumped Storage | South Carolina | ~1,064 MW | ~ 1,884.7 GWh | Part of Southeastern balancing resources |
14 | Big Creek (California) | California | ~1,050 MW | ~ 4,000 GWh | Historic project, multiple stations aggregated |
15 | Boundary Dam | Washington (Seattle City Light) | ~1,003 MW | ~4,004 GWh in the 2018 sample | Significant regional supply for Seattle utilities |
16 | McNary Dam | Oregon/Washington | ~986 MW | ~5,440.8 GWh | Part of the Columbia River system |
17 | Lower Monumental Dam | Washington | ~810 MW | ~2,383 GWh | Another Columbia River run-of-river dam |
18 | Wells Dam | Washington | ~774 MW | ~4,439 GWh | Mid-Columbia smaller scale |
19 | Rock Island Dam | Washington | ~622.5 MW | ~2,652 GWh | One of the older yet still significant units |
20 | Brownlee Dam | Idaho/Oregon | ~585 MW | ~2,406.8 GWh | Part of the Hells Canyon/Snake River system |
Conclusion
Hydropower remains a significant source of clean energy for the world. The 20 largest hydro plants in the United States highlight hydropower’s importance for a clean energy future. Hydropower stands apart for its reliability, operational flexibility, and ability to deliver large-scale power generation. Many of these plants provide electricity for grid services and as well as store energy. Today, these legacy assets are being upgraded with digital controls and modern technologies, ensuring hydropower remains a key resource in the U.S. energy mix.
FAQs
1. Where are the larger number of hydro plant facilities in the U.S.?
2. Will hydropower fit into a clean energy future?
3. Can hydropower plants contribute to the environment?
4. Are new large hydro plants being constructed in the U.S.?
5. Which rivers contain the greatest number of plants?
Disclaimer: Any opinions expressed in this blog do not necessarily reflect the opinions of Certrec. This content is meant for informational purposes only.
