Clean Energy
The 30 Largest U.S. Hydropower Plants
The following content is sponsored by the National Public Utilities Council
The 30 Largest Hydropower Plants in the U.S.
Did you know that the largest power plant in the United States is hydroelectric?
Hydropower is the second-largest source of U.S. renewable electricity generation and the largest source of power in seven different states.
The above infographic from the National Public Utilities Council charts the 30 largest U.S. hydropower plants and shows how droughts are starting to affect hydroelectricity. This is part one of two in the Hydropower Series.
Dam, That’s Large: U.S. Hydropower Plants by Generation
The top 30 hydropower plants account for around 50% of U.S. hydroelectric generation annually.
Hydropower plants are most prevalent in the Northwestern states of Washington and Oregon, jointly hosting 16 of the top 30 plants.
Plant Name | State | 2021 Avg. Net Electricity Generation (MWh) | % of Total Hydropower Generation |
---|---|---|---|
Grand Coulee | Washington | 19,550,777 | 7% |
Robert Moses - Niagara | New York | 14,186,130 | 5% |
Chief Joseph | Washington | 11,092,216 | 4% |
John Day | Oregon | 9,041,083 | 3% |
Robert Moses - St. Lawrence | New York | 6,906,420 | 3% |
The Dalles | Oregon | 6,613,185 | 2% |
Rocky Reach | Washington | 5,935,038 | 2% |
McNary | Oregon | 5,369,726 | 2% |
Wanapum | Washington | 4,820,651 | 2% |
Bonneville | Oregon | 4,659,483 | 2% |
Priest Rapids | Washington | 4,462,873 | 2% |
Wells | Washington | 4,153,466 | 2% |
Glen Canyon | Arizona | 3,772,010 | 1% |
Boundary | Washington | 3,730,184 | 1% |
Rock Island | Washington | 2,532,044 | 0.9% |
Wilson Dam | Alabama | 2,404,440 | 0.9% |
Lower Monumental | Washington | 2,240,264 | 0.8% |
Oahe | South Dakota | 2,181,664 | 0.8% |
Lower Granite | Washington | 2,171,590 | 0.8% |
Little Goose | Washington | 2,156,654 | 0.8% |
Brownlee | Idaho | 2,154,411 | 0.8% |
Libby | Montana | 2,122,863 | 0.8% |
Hoover Dam - NV | Nevada | 2,044,127 | 0.7% |
Garrison | North Dakota | 1,941,731 | 0.7% |
Shasta | California | 1,907,761 | 0.7% |
Hells Canyon | Oregon | 1,900,591 | 0.7% |
Conowingo | Maryland | 1,885,395 | 0.7% |
Dworshak | Idaho | 1,773,911 | 0.6% |
Hoover Dam - AZ | Arizona | 1,713,563 | 0.6% |
Noxon Rapids | Montana | 1,710,754 | 0.6% |
Total | N/A | 137,135,005 | 50% |
The Grand Coulee Dam in Washington is the country’s largest power plant. It generates over 19.5 million megawatt-hours (MWh) of electricity annually and supplies it to eight states, including parts of Canada. Overall, 10 of the top 30 hydropower plants are in Washington.
The Robert Moses Power Plant is a close second, located around 5 miles downstream from Niagara Falls. Combined with the nearby Lewiston Pump Generation Plant, it is New York’s single-largest source of electricity.
While hydropower is a relatively reliable renewable power source, prolonged dry conditions can put it at risk. That is the case for both the Glen Canyon and Hoover Dams, which are no longer running at previous capacities.
Running Dry: Water Scarcity and Hydropower
The Southwestern U.S. has been in a “megadrought”—a prolonged drought lasting longer than two decades—since 2000. In fact, it has gotten so severe that the past 22 years mark the region’s driest spell in 1,200 years.
Consequently, many Southwestern reservoirs have below-average storage levels. When these levels fall below a certain threshold, hydropower plants can no longer generate power.
In particular, storage levels are precariously low at Lake Mead (Hoover Dam) and Lake Powell (Glen Canyon Dam), which supply most of Arizona’s hydroelectricity. They are also the two largest reservoirs in the country.
Here’s a look at how filled these reservoirs are as of Dec. 4, 2022:
Reservoir | Total Storage (acre ft) | Current Storage (acre ft) | % Full |
---|---|---|---|
Lake Mead (Hoover Dam) | 26,120,000 | 7,194,077 | 28% |
Lake Powell (Glen Canyon Dam) | 24,322,000 | 5,696,907 | 23% |
To put those figures into perspective, here’s an animation looking at Lake Powell’s surface area changes from 2018 to 2022:
Shrinking water levels at reservoirs threaten the reliability of hydropower and the millions of people that rely on it for electricity. As droughts become more frequent due to climate change, what does the future of hydropower look like?
Find out in Part 2 of the Hydropower Series, where we’ll dive deeper into how droughts are affecting dams and how hydropower fits into the bigger decarbonization picture.
Clean Energy
Visualized: Renewable Energy Capacity Through Time (2000–2023)
This streamgraph shows the growth in renewable energy capacity by country and region since 2000.
Visualized: Renewable Energy Capacity Through Time (2000–2023)
Global renewable energy capacity has grown by 415% since 2000, or a compound annual growth rate (CAGR) of 7.4%.
However, many large and wealthy regions, including the United States and Europe, maintain a lower average annual renewable capacity growth.
This chart, created in partnership with the National Public Utilities Council, shows how each world region has contributed to the growth in renewable energy capacity since 2000, using the latest data release from the International Renewable Energy Agency (IRENA).
Renewable Energy Trends in Developed Economies
Between 2000 and 2023, global renewable capacity increased from 0.8 to 3.9 TW. This was led by China, which added 1.4 TW, more than Africa, Europe, and North America combined. Renewable energy here includes solar, wind, hydro (excluding pumped storage), bioenergy, geothermal, and marine energy.
During this period, capacity growth in the U.S. has been slightly faster than what’s been seen in Europe, but much slower than in China. However, U.S. renewable growth is expected to accelerate due to the recent implementation of the Inflation Reduction Act.
Overall, Asia has shown the greatest regional growth, with China being the standout country in the continent.
Region | 2000–2023 Growth | 10-Year Growth (2013–2023) | 1-Year Growth (2022–2023) |
---|---|---|---|
Europe | 313% | 88% | 10% |
China | 1,817% | 304% | 26% |
United States | 322% | 126% | 9% |
Canada | 57% | 25% | 2% |
It’s worth noting that Canada has fared significantly worse than the rest of the developed world since 2000 when it comes to renewable capacity additions. Between 2000 and 2023, the country’s renewable capacity grew only by 57%.
Trends in Developing Economies
Africa’s renewable capacity has grown by 184% since 2000 with a CAGR of 4%.
India is now the most populous country on the planet, and its renewable capacity is also rapidly growing. From 2000–2023, it grew by 604%, or a CAGR of 8%.
It is worth remembering that energy capacity is not always equivalent to power generation. This is especially the case for intermittent sources of energy, such as solar and wind, which depend on natural phenomena.
Despite the widespread growth of renewable energy worldwide, IRENA emphasizes that global renewable generation capacity must triple from its 2023 levels by 2030 to meet the ambitious targets set by the Paris Agreement.
Learn how the National Public Utilities Council is working toward the future of sustainable electricity.
Clean Energy
Visualized: The Four Benefits of Small Modular Reactors
What advantages do small modular reactors offer compared to their traditional counterparts?
Visualized: The Four Benefits of Small Modular Reactors
Nuclear power has a crucial role to play on the path to net zero. Traditional nuclear plants, however, can be costly, resource-intensive, and take up to 12 years to come online.
Small modular reactors (SMR) offer a possible solution.
Created in partnership with the National Public Utilities Council, this infographic explores some of the benefits SMRs can offer their traditional counterparts. Let’s dive in.
The Four Key Benefits of SMRs, Explained
An SMR is a compact nuclear reactor that is typically less than 300 megawatts electric (MWe) in capacity and manufactured in modular units.
Here are some of the benefits they offer.
#1: Lower Costs
SMRs require a lower upfront capital investment due to their compact size.
SMRs can also match the per-unit electricity costs of traditional reactors due to various economic efficiencies related to their modular design, including design simplification, factory fabrication, and potential for regulatory harmonization.
#2: Quicker Deployment
Traditional nuclear plants can take up to 12 years to become operational. This is primarily due to their site-specific designs and substantial on-site labor involved in construction.
SMRs, on the other hand, are largely manufactured in factories and are location-independent, which minimizes on-site labor and expedites deployment timelines to as little as three years. This means they can be deployed relatively quickly to provide emissions-free electricity to the grid, supporting growing electricity needs.
#3: Siting Flexibility and Land Efficiency
SMRs have greater siting flexibility compared to traditional reactors due to their smaller size and modular design. In addition, they can utilize land more effectively than traditional reactors, yielding a higher output of electrical energy per unit of land area.
Rolls-Royce SMR, UK (Proposed) | Median-Sized U.S. Nuclear Plant | |
---|---|---|
Capacity | 470 MW | 1,000 MW |
Area Requirement | 10 Acres* | 832 Acres |
Land/Space Efficiency | 47 MW/Acre | 1.2 MW/Acre |
*Estimated area requirement
Given their flexibility, SMRs are also suitable for installation on decommissioned coal power plant sites, which can support the transition to clean electricity while utilizing existing transmission infrastructure.
#4: Safety
SMRs have simpler designs, use passive cooling systems, and require lower power and operating pressure, making them inherently safer to operate than traditional reactors.
They also have different refueling needs compared to traditional plants, needing refueling every 3–7 years instead of the 1–2 years typical for large plants. This minimizes the transportation and handling of nuclear fuel, mitigating the risk of accidents.
The Road Ahead
As of early 2024, only five SMRs are operating worldwide. But with several other projects under construction and nearly 20 more in advanced stages of development, SMRs hold promise for expanding global emission-free electricity capacity.
With that said, certain obstacles remain for the wide-scale adoption of SMRs in the United States, which was particularly apparent in the 2023 cancellation of the NuScale SMR project.
To fully realize the benefits of SMRs and advance decarbonization efforts, a focus on financial viability, market readiness, and broader utility and public support may be essential.
Learn how the National Public Utilities Council is working toward the future of sustainable electricity.
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