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U.S. States with the Most Hydropower Generation

U.S. States with the Most Hydropower Generation

Energy & Resources, U.S. StatesAugust 13, 2026

Hydropower generation for millions of homes represents a major engineering accomplishment. The Columbia River Gorge and Niagara Falls exemplify the substantial energy potential found in specific geographic regions. This report analyzes the top 17 hydropower-producing states in the United States, utilizing recent data from the U.S. Energy Information Administration, Wikipedia, and official government dam records.

The data, expressed in billion kilowatt-hours of net generation, highlight the influence of geography, precipitation, and ongoing infrastructure investment. Each state is evaluated to identify the primary factors affecting hydropower output. The analysis offers insights relevant to energy data analysis, policy assessment, and the examination of electricity supply sources.

The Continued Importance of Hydropower in 2026

Hydropower remains the largest source of renewable electricity in the United States, despite increasing interest in wind and solar energy. In 2023, conventional hydroelectric generation accounted for approximately 6 percent of all utility-scale electricity nationwide, totaling about 240 billion kilowatt-hours of clean energy. Although this share is modest compared to natural gas or coal, several states demonstrate a much higher reliance on hydropower. Nearly half of the nation’s hydropower capacity is concentrated in three states: Washington, California, and Oregon, underscoring the significant influence of regional geography on energy production. Major rivers such as the Columbia, Tennessee, and Missouri traverse steep terrain, enabling extensive dam construction during the twentieth century. This regional concentration is frequently overlooked in national energy statistics and serves as a central focus of this analysis.

Overview of the Hydropower Data Visualization

The 2024 data presented in this report are derived from an infographic created using U.S. Energy Information Administration (EIA) tables, which provide each state’s net hydroelectric generation in billion kilowatt-hours for the most recent year available. The dataset highlights states such as Washington with 61 billion kWh, and California and New York with outputs in the high twenties, while several smaller states report lower generation levels. To aid interpretation, the report incorporates additional context, historical background, and analytical commentary. Factors including precipitation, river gradient, dam infrastructure, and the extent of federal investment determine each state’s ranking. The infographic is referenced throughout the discussion to connect each section to the relevant state data.

Washington: Leading State in Hydropower Generation

Washington leads the nation in hydropower generation, producing 61 billion kilowatt-hours in 2024, more than double the output of California, the second-ranked state. This dominance is attributed to the Columbia River and its tributaries, which traverse steep canyons and provide optimal conditions for large-scale dams. Grand Coulee Dam is the largest power plant in the United States, generating over 19.5 million megawatt-hours annually and supplying electricity to eight states and parts of Canada. Hydropower accounts for about 59 percent of Washington’s total electricity generation, a proportion significantly higher than in most other states. Nine of Washington’s ten largest power plants are hydroelectric, underscoring the centrality of water power to the state’s energy system.

Additionally, ten of the nation’s top 30 hydropower plants are located in Washington, a concentration unmatched by any other state. This prominence results from both favorable geography and sustained federal and state investment in the Columbia River basin. Washington is widely recognized as the leading state in American hydropower.

Washington generates about 61 billion kilowatt-hours of hydropower annually, the highest total of any U.S. state.
Grand Coulee Dam in Washington is the largest power plant of any kind in the United States.
Hydropower supplies close to 59 percent of Washington’s total electricity generation.
Nine of Washington’s ten largest power plants by capacity are hydroelectric facilities.
Ten of the nation’s top 30 hydropower plants are located within Washington state.
Washington typically contributes between one-fourth and one-third of all U.S. conventional hydroelectric generation each year.
The Columbia River system powers a dense cluster of major dams across eastern and central Washington.
Chief Joseph Dam in Washington ranks among the largest hydroelectric facilities in the entire country.

California: Hydropower’s Role in Statewide Electricity Supply

California ranks second in hydroelectric generation, producing 29 billion kilowatt-hours in 2024, a result of its large geographic area and mountainous terrain. Although California is frequently associated with solar energy, the Sierra Nevada and northern rivers have supported hydroelectric plants for more than a century. The state also leads the nation in pumped-storage hydroelectric capacity, accounting for approximately 17 percent of the national total. Pumped storage functions as a large-scale energy storage system by moving water uphill during periods of low demand and releasing it during peak demand. The combination of conventional hydropower and pumped storage enhances California’s capacity to maintain grid stability in the western United States. Conventional hydropower supplies about 15 percent of California’s electricity, a smaller proportion than in Washington but still significant given the state’s high energy demand. Hydropower output in California is highly variable due to drought and snowpack fluctuations, with dry winters substantially reducing generation.

California generates approximately 29 billion kilowatt-hours of hydroelectric power annually.
California holds the largest share of pumped-storage hydroelectric capacity in the nation at about 17 percent.
Conventional hydropower supplies roughly 15 percent of California’s total in-state electricity generation.
California, Washington, and Oregon together hold about half of all U.S. hydropower generating capacity.
California’s hydropower output fluctuates significantly with drought and snowpack conditions each year.
The Sierra Nevada mountain range hosts many of California’s major hydroelectric facilities.
California ranks among the top five states for installed hydropower capacity nationwide.
California’s dual role in conventional and pumped-storage hydropower makes it a critical grid-balancing state.

New York: Hydropower Leadership in the Northeastern United States

New York generated 28 billion kilowatt-hours of hydroelectricity in 2024, positioning it as the leading hydropower state east of the Mississippi River. Niagara Falls is central to this achievement, home to the Robert Moses Niagara Power Plant, which produces over 14 million megawatt-hours annually and ranks as the second-largest hydroelectric facility in the United States. New York’s hydropower legacy extends over a century, with Niagara Falls representing early industrial utilization of water resources. Hydropower accounts for about 21 percent of New York’s electricity supply, a notable proportion for a state with a large and diverse population and industrial sector. The St. Lawrence River also contributes significantly, with the Robert Moses–St. Lawrence plant generating millions of megawatt-hours each year. New York demonstrates that substantial hydropower generation is achievable in eastern states, challenging the perception that such capacity is confined to the mountainous western United States.

New York generates roughly 28 billion kilowatt-hours of hydroelectric power each year.
New York is the leading hydropower-producing state east of the Mississippi River.
The Robert Moses Niagara Power Plant is the second-largest hydroelectric facility in the United States.
Niagara Falls has powered New York’s grid since the earliest days of large-scale hydroelectricity.
Hydropower supplies about 21 percent of New York’s total in-state electricity generation.
The Robert Moses–St. Lawrence plant adds millions of additional megawatt-hours to New York’s total.
New York holds roughly 6 percent of total U.S. conventional hydroelectric generation capacity.
New York proves that major hydropower output is not exclusive to western mountain states.

Oregon: The Columbia’s Second Powerhouse State

Oregon produced 27 billion kilowatt-hours of hydroelectric power in 2024, with the majority of this output originating from the Columbia River system, which it shares with Washington. Oregon and Washington are frequently grouped in hydropower rankings due to the presence of major dams such as John Day, The Dalles, McNary, and Bonneville along their shared border on the Columbia River. Hydropower supplies approximately half of Oregon’s electricity, placing it among the most hydro-dependent states nationally. This dependence highlights the significance of precipitation and river flow in Oregon’s energy portfolio. The John Day Dam alone generates over 9 million megawatt-hours per year, ranking among the top ten hydroelectric facilities in the United States. Together, Oregon and Washington host 16 of the nation’s 30 largest hydropower plants, all located along the Columbia River. This longstanding tradition of dam construction has been central to establishing the Pacific Northwest’s reputation for clean energy.

Oregon generates approximately 27 billion kilowatt-hours of hydroelectric power annually.
Hydropower supplies roughly half of Oregon’s total in-state electricity generation.
John Day Dam in Oregon produces over 9 million megawatt-hours of electricity each year.
Oregon and Washington together host 16 of the nation’s top 30 hydropower plants.
The Dalles Dam and Bonneville Dam are both major hydroelectric facilities located in Oregon.
Oregon holds roughly 10 percent of total U.S. conventional hydroelectric generation capacity.
The Columbia River system links Oregon’s hydropower output directly to Washington’s dam network.
Oregon ranks among the most hydro-dependent states in the entire country by generation share.

Idaho: Hydropower Generation from Mountain Snowpack

Idaho generated 9.2 billion kilowatt-hours of hydroelectric power in 2024, primarily due to mountain snowpack that sustains rivers such as the Snake and Clearwater. Hydropower has historically supplied nearly 69 percent of Idaho’s electricity, ranking among the highest shares nationally. This high proportion is facilitated by Idaho’s relatively small population and abundant water resources, enabling hydropower to meet a substantial share of the state’s energy demand. The Brownlee Dam on the Snake River is among the top 20 hydroelectric plants in the United States. Idaho’s significant reliance on hydropower also renders its electricity supply vulnerable to drought and snowpack variability. As a result, effective water management and energy planning are closely linked in Idaho, illustrating both the advantages and challenges of a hydropower-dependent energy system.

Idaho generates approximately 9.2 billion kilowatt-hours of hydroelectric power annually.
Hydropower has historically supplied close to 69 percent of Idaho’s total in-state electricity generation.
Brownlee Dam on the Snake River ranks among the nation’s top 20 hydroelectric facilities.
Idaho’s hydropower output is closely tied to seasonal mountain snowpack levels.
The Snake River and Clearwater River are central to Idaho’s hydroelectric infrastructure.
Idaho ranks among the highest states nationally for hydropower as a share of total generation.
Idaho’s relatively small population allows hydropower to cover an outsized share of demand.
Drought and reduced snowpack directly threaten Idaho’s hydroelectric output year over year.

Montana: River-Based Hydropower in a Diversified Grid

Montana generated 9.2 billion kilowatt-hours of hydroelectric power in 2024, nearly matching Idaho for sixth place nationally. Much of this output is derived from rivers in the Rocky Mountains, which support a network of dams constructed since the early twentieth century. Hydropower has historically supplied nearly 39 percent of Montana’s electricity, a notable figure given the state’s reliance on coal and wind resources. Montana’s energy portfolio is more diversified than those of states dependent on a single source. In recent years, Montana’s hydropower output has increased more rapidly than in some neighboring states, due to sustained investment in dam infrastructure. The state’s large land area and low population density minimize land-use conflicts associated with hydropower development. Montana demonstrates that states with smaller populations can still make significant contributions to national hydropower capacity.

Montana generates approximately 9.2 billion kilowatt-hours of hydroelectric power each year.
Hydropower has historically supplied close to 39 percent of Montana’s total in-state electricity generation.
Montana’s hydroelectric output nearly ties with Idaho for sixth place among all U.S. states.
Rivers flowing from the Rocky Mountains feed most of Montana’s hydroelectric dam network.
Montana’s lower population density reduces land-use conflicts around hydroelectric infrastructure.
Montana’s grid blends hydropower with significant coal and wind generation.
Montana’s hydropower generation increased year over year in the most recent EIA reporting period.
Montana remains one of the more hydro-reliant states in the northern Rocky Mountain region.

Alabama: Hydropower Development on the Tennessee River

Alabama produced 8.4 billion kilowatt-hours of hydroelectric power in 2024, primarily due to the Tennessee Valley Authority’s extensive dam system on the Tennessee River. Wilson Dam is a central component of this network. Constructed in 1924, it is the largest conventional hydroelectric facility in the TVA system and was originally built to supply power to nitrate plants during World War I. It subsequently became an integral part of Alabama’s power grid. The dam generates over 2.3 million megawatt-hours annually and contains 21 generating units with a summer net dependable capacity exceeding 650 megawatts. Hydropower accounts for about 5 to 6 percent of Alabama’s electricity generation, a modest share compared to the Pacific Northwest but significant within the TVA system. Wilson Lake, the dam’s reservoir, features 166 miles of shoreline and serves both recreational and power generation purposes. This multi-use approach aligns with the TVA’s original New Deal objectives.

Alabama generates approximately 8.4 billion kilowatt-hours of hydroelectric power annually.
Wilson Dam is the largest conventional hydroelectric facility in the entire TVA system.
Wilson Dam was originally constructed to power nitrate plants during World War I.
Wilson Dam produces over 2.3 million megawatt-hours of electricity each year.
Wilson Dam features 21 generating units with a summer net dependable capacity above 650 megawatts.
Hydropower supplies roughly 5 to 6 percent of Alabama’s total in-state electricity generation.
Wilson Lake, the reservoir behind Wilson Dam, offers 166 miles of shoreline for recreation.
Alabama’s hydroelectric output relies heavily on the Tennessee Valley Authority’s regional dam network.

Tennessee: TVA’s Home Base for Hydroelectric Power

Tennessee produced 8.3 billion kilowatt-hours of hydroelectric power in 2024, reflecting its role as the headquarters state for the Tennessee Valley Authority’s extensive dam system. This network originated in the 1930s, when the federal government constructed numerous dams across the Tennessee River basin to provide flood control, navigation, and electricity to a historically underdeveloped region. The TVA hydroelectric system now includes 29 power-generating dams throughout the Tennessee River system, as well as the Raccoon Mountain pumped-storage plant near Chattanooga.

The TVA project exemplifies American regional planning, having transformed the economies of seven states over the past century. Hydropower supplies approximately 11 to 13 percent of Tennessee’s total in-state electricity generation, according to recent monthly EIA data. Dams such as Norris, Fontana, and Chickamauga each contribute, although none match the scale of Wilson Dam in neighboring Alabama. Tennessee’s hydropower identity is closely tied to the TVA’s broader mission, and understanding one provides insight into the other.

Tennessee generates approximately 8.3 billion kilowatt-hours of hydroelectric power annually.
The Tennessee Valley Authority operates 29 power-generating dams across the Tennessee River system.
Raccoon Mountain near Chattanooga is TVA’s major pumped-storage hydroelectric facility.
Hydropower supplies roughly 11 to 13 percent of Tennessee’s total in-state electricity generation.
TVA’s dam-building program began in the 1930s as part of New Deal regional development.
Norris Dam was one of the earliest major hydroelectric projects built by TVA in Tennessee.
Tennessee’s hydroelectric system provides flood control and navigation alongside electricity generation.
Tennessee’s dam network spans tributaries including the Holston, Clinch, and French Broad rivers.

Arizona: Desert Power From the Colorado River

Arizona generated 5.3 billion kilowatt-hours of hydroelectric power in 2024, with nearly all production originating from the Colorado River along its western border. Despite its arid climate, Arizona ranks highly in hydropower output due to major facilities such as Glen Canyon Dam and Hoover Dam. Glen Canyon Dam alone produces nearly 3.8 million megawatt-hours annually, placing it among the top 15 hydroelectric plants in the United States. Arizona demonstrates that significant hydropower generation is possible in desert regions when supported by a major river system. Hydropower typically accounts for 6 to 7 percent of Arizona’s electricity supply. The state also shares the benefits of Colorado River hydropower with neighboring states, including Nevada, as Hoover Dam’s output is distributed across multiple jurisdictions. This arrangement illustrates how a single river system can influence energy policy and supply across state boundaries.

Arizona generates approximately 5.3 billion kilowatt-hours of hydroelectric power annually.
Glen Canyon Dam produces nearly 3.8 million megawatt-hours of electricity each year.
Glen Canyon Dam ranks among the top 15 hydroelectric facilities in the United States.
Arizona’s hydropower output depends heavily on the Colorado River system.
Hydropower has historically supplied roughly 6 to 7 percent of Arizona’s total generation.
Hoover Dam’s regional benefits are shared between Arizona, Nevada, and California.
Arizona proves that arid states can still rank highly in national hydropower output.
The Colorado River basin shapes energy policy across multiple southwestern states simultaneously.

North Carolina: The Catawba River’s Textile-Era Legacy

North Carolina produced 4.8 billion kilowatt-hours of hydroelectric power in 2024, primarily from a series of dams along the Catawba River established more than a century ago. The system originated in 1919, when the predecessor to Duke Energy constructed the Bridgewater Hydro Station to support the region’s expanding textile industry. North Carolina’s hydropower development is closely linked to its industrial history, as these dams were initially constructed to serve factories rather than residential electricity grids. Currently, Duke Energy operates approximately 30 conventional hydroelectric facilities across North Carolina and South Carolina, ranked by their average electricity production. Cowans Ford Hydro Station is among the largest in this network, providing approximately 350 megawatts of average capacity. Hydropower’s share of North Carolina’s total electricity generation remains modest, generally below 5 percent, yet the enduring infrastructure continues to serve as a significant regional asset. The Catawba River chain represents a notable case study in Southeastern energy history.

North Carolina generates approximately 4.8 billion kilowatt-hours of hydroelectric power annually.
Bridgewater Hydro Station began operating in 1919 to power the regional textile industry.
Duke Energy operates roughly 30 conventional hydroelectric facilities across the Carolinas.
Cowans Ford Hydro Station contributes around 350 megawatts of average generating capacity.
The Catawba River hosts one of the oldest continuously operating hydro dam chains in the country.
North Carolina’s hydropower share of total in-state generation remains under 5 percent.
Lake James, created by three earthen dams, supports North Carolina’s hydroelectric infrastructure.
North Carolina’s hydro network reflects over a century of continuous industrial-era engineering.

South Dakota: The Missouri River’s Prairie Powerhouse

South Dakota generated 4.6 billion kilowatt-hours of hydroelectric power in 2024, primarily from the Oahe Dam on the Missouri River near Pierre. Oahe Dam alone produces over 2.1 million megawatt-hours each year, ranking among the top 20 hydroelectric plants in the United States. The dam created Lake Oahe, the fourth-largest reservoir in the country, which extends 231 miles up the Missouri River toward North Dakota. Hydropower has historically supplied nearly 48 percent of South Dakota’s electricity, a substantial share for a prairie state. Dedicated by President John F. Kennedy in 1962, Oahe Dam continues to provide electricity to North Dakota, South Dakota, Nebraska, Minnesota, and Montana. This example demonstrates how a single Missouri River dam can supply power to an entire region. South Dakota’s experience underscores the importance of geography, rather than population, in shaping a state’s clean energy profile.

South Dakota generates approximately 4.6 billion kilowatt-hours of hydroelectric power annually.
Oahe Dam produces over 2.1 million megawatt-hours of electricity each year.
Lake Oahe is the fourth-largest reservoir in the entire United States.
Hydropower has historically supplied close to 48 percent of South Dakota’s total generation.
Oahe Dam was dedicated by President John F. Kennedy in 1962.
Oahe Dam supplies electricity across five states in the north-central United States.
The Missouri River mainstem dam system includes Oahe as one of six major facilities.
South Dakota shows that prairie states can still rank highly in national hydropower output.

Kentucky: The Ohio and Cumberland Rivers at Work

Kentucky produced 4.1 billion kilowatt-hours of hydroelectric power in 2024, utilizing a combination of Ohio River locks and Cumberland River dams operated in partnership with federal agencies. Kentucky’s hydropower infrastructure is smaller and more dispersed than that of states such as Washington or Tennessee, relying on multiple mid-sized facilities rather than a single large dam. This distributed approach reflects Kentucky’s relatively flat terrain, which limits the capacity of individual dams but allows the network as a whole to contribute to the grid. Hydropower’s share of Kentucky’s total in-state electricity generation typically remains in the low single digits, representing a modest yet consistent contribution alongside the state’s historical reliance on coal. Several Kentucky dams operate in coordination with the Tennessee Valley Authority’s broader Cumberland River system, integrating the state’s output into a regional network that also serves Tennessee and Alabama. Kentucky’s hydropower system is therefore closely connected to those of its southern neighbors, positioning the state at a key intersection of multiple river-basin authorities.

Kentucky generates approximately 4.1 billion kilowatt-hours of hydroelectric power annually.
Kentucky’s hydropower comes from a mix of Ohio River and Cumberland River facilities.
Kentucky relies on multiple mid-sized dams rather than one dominant mega-facility.
Several Kentucky dams operate in coordination with the Tennessee Valley Authority system.
Kentucky’s hydropower share of total in-state generation typically remains in the low single digits.
Kentucky’s flatter terrain compared to western states limits individual dam capacity.
Kentucky’s grid has historically leaned heavily on coal alongside its hydroelectric contribution.
Kentucky’s river-basin dams connect its hydropower output to neighboring southern states.

Arkansas: The Ozark Region’s Steady Contributor

Arkansas generated 3.2 billion kilowatt-hours of hydroelectric power in 2024, primarily from dams on the Arkansas and White Rivers in the Ozark Mountains. Although Arkansas’s hydropower network is less prominent than the large-scale systems of the Pacific Northwest, it remains a significant component of the state’s energy portfolio. Notably, Arkansas’s hydropower output has remained stable over several years, in contrast to some western states affected by drought. Hydropower typically accounts for about 4 percent of Arkansas’s electricity generation, representing a modest but consistent share. The Army Corps of Engineers operates several major hydroelectric plants in Arkansas as part of integrated flood-control and power generation projects along the Arkansas River. This dual-purpose approach is similar to Tennessee Valley Authority projects in the eastern United States. Arkansas demonstrates that mid-sized states with moderate rainfall can maintain a reliable hydropower supply through effective river management.

Arkansas generates approximately 3.2 billion kilowatt-hours of hydroelectric power annually.
Arkansas’s hydropower dams are concentrated along the Arkansas and White River systems.
The Ozark Mountains provide the elevation change needed for Arkansas’s hydroelectric facilities.
Hydropower’s share of Arkansas’s total in-state generation has historically hovered around 4 percent.
The Army Corps of Engineers operates several major hydroelectric facilities in Arkansas.
Arkansas’s hydropower output has remained relatively stable across multiple reporting years.
Flood-control projects along the Arkansas River double as hydroelectric generation sites.
Arkansas demonstrates that consistent river management can sustain steady hydropower output.

Maine: New England’s Quiet Hydropower Leader

Maine produced 2.9 billion kilowatt-hours of hydroelectric power in 2024, making it the leading hydropower state in New England despite its relatively small geographic size. Although Maine is often associated with its coastal industries, its extensive network of rivers and historic dams has powered mills and communities for over a century. Maine’s hydropower infrastructure demonstrates how legacy industrial systems can be adapted to support contemporary clean-energy objectives without major redesign.

Hydropower has historically supplied nearly 26 percent of Maine’s total in-state electricity generation, ranking among the highest shares in the eastern United States. The state’s dams are generally smaller and more numerous than the large-scale facilities in the western states, reflecting Maine’s dense river network rather than dependence on a few major waterways. This distributed system enhances Maine’s resilience to localized drought, in contrast to states reliant on a single river. Maine serves as a valuable case study for energy resilience in New England.

Maine generates approximately 2.9 billion kilowatt-hours of hydroelectric power annually.
Maine is the leading hydropower-producing state in the entire New England region.
Hydropower has historically supplied close to 26 percent of Maine’s total in-state generation.
Maine’s hydroelectric network consists of many smaller dams rather than a few mega-facilities.
Maine’s dams originally powered the state’s historic mill and manufacturing industries.
Maine’s distributed hydropower system offers resilience against localized drought conditions.
Maine’s dense river network supports one of the highest hydropower shares in the eastern U.S.
Maine’s hydroelectric infrastructure reflects over a century of continuous industrial use.

Georgia: The Southeast’s Corps of Engineers Network

Georgia generated 2.2 billion kilowatt-hours of hydroelectric power in 2024, utilizing a combination of Army Corps of Engineers dams and smaller local facilities. Georgia’s hydropower system is closely integrated with the Southeastern power grid, operating in coordination with Alabama and South Carolina. Although Georgia’s total hydropower output is relatively modest, it contributes valuable diversity to a region primarily powered by natural gas and nuclear energy. The state also possesses significant pumped-storage capacity, accounting for about 8 percent of the national total, which enhances Georgia’s role in regional grid stability beyond what conventional hydropower figures alone suggest. While Georgia’s rivers lack the dramatic elevation changes found in western states, they continue to provide a reliable source of clean electricity. Georgia’s participation in both conventional and pumped-storage hydropower is a key component of Southeastern energy infrastructure.

Georgia generates approximately 2.2 billion kilowatt-hours of hydroelectric power annually.
Georgia’s hydropower network relies heavily on Army Corps of Engineers dam facilities.
Georgia holds roughly 8 percent of the national pumped-storage hydroelectric capacity total.
Georgia’s hydropower output supports grid diversity in a region dominated by gas and nuclear.
Georgia’s rivers lack the dramatic elevation change found in western mountain states.
Georgia’s pumped-storage role gives it outsized influence on regional grid stability.
Georgia’s hydroelectric facilities work in tandem with neighboring Alabama and South Carolina systems.
Georgia’s contribution, while modest, adds meaningful clean-energy diversity to the Southeast.

South Carolina: Pumped Storage and the Catawba-Wateree System

South Carolina generated 2.2 billion kilowatt-hours of hydroelectric power in 2024, placing it alongside Georgia among the top 17 hydropower-producing states. A significant portion of South Carolina’s hydropower is generated from the Catawba-Wateree river chain, which is shared with North Carolina and primarily operated by Duke Energy. South Carolina is notable for its substantial pumped-storage capacity, accounting for about 13 percent of the national total and ranking among the highest in the country.

The Jocassee and Bad Creek pumped-storage stations play a critical role in balancing the grid during periods of peak demand. Consequently, South Carolina has a greater impact on regional grid stability than its conventional hydropower output alone would indicate. Additionally, the state’s hydroelectric facilities provide recreational opportunities and water supply in the Piedmont region, reflecting a multi-purpose approach similar to that of TVA projects in the northern states. South Carolina’s contributions to grid balancing are significant, despite its modest conventional hydropower total.

South Carolina generates approximately 2.2 billion kilowatt-hours of hydroelectric power annually.
South Carolina holds roughly 13 percent of the national pumped-storage hydroelectric capacity total.
The Jocassee Pumped-Storage Generating Station is one of South Carolina’s largest hydro facilities.
The Bad Creek Hydroelectric Station plays a major role in regional grid balancing.
South Carolina shares the Catawba-Wateree river chain with neighboring North Carolina.
South Carolina’s hydropower facilities also support regional water supply and recreation needs.
South Carolina ranks among the top states nationally for pumped-storage capacity.
South Carolina’s grid influence exceeds what its conventional hydropower ranking alone suggests.

Wisconsin: The Upper Midwest’s Small-Scale Hydro Network

Wisconsin produced 2.1 billion kilowatt-hours of hydroelectric power in 2024, completing the list of the top 17 hydropower-producing states with a network primarily centered on smaller rivers throughout the state’s interior. Wisconsin’s hydropower facilities are generally older, smaller, and more numerous than the large-scale dams found in western states, reflecting the state’s gentler terrain and history of mill-town development. Wisconsin’s inclusion in this ranking demonstrates that significant hydropower contributions do not require dramatic mountains or major rivers. Many of the state’s hydroelectric facilities were constructed more than a century ago to power paper mills and small manufacturing towns.

Hydropower’s share of Wisconsin’s total in-state electricity generation remains modest, typically in the low single digits, yet the infrastructure holds considerable historical and cultural significance. Many dams are locally owned or operated by smaller utilities rather than large federal agencies, imparting a community-based character to Wisconsin’s hydropower sector. Wisconsin exemplifies small-scale, legacy hydropower infrastructure in contrast to the large-scale projects common in other leading states.

Wisconsin generates approximately 2.1 billion kilowatt-hours of hydroelectric power annually.
Wisconsin’s hydropower network consists mostly of smaller, older dam facilities.
Many Wisconsin hydro dams originally powered paper mills and small manufacturing towns.
Hydropower’s share of Wisconsin’s total in-state generation remains in the low single digits.
Wisconsin’s dams are often locally owned rather than managed by large federal agencies.
Wisconsin’s hydroelectric infrastructure reflects over a century of small-town industrial history.
Wisconsin rounds out the top 17 hydropower-producing states in the United States.
Wisconsin proves that gentler terrain can still support a meaningful, long-lasting hydro network.

What This Ranking Tells Us About American Energy Geography

Analysis of these 17 states reveals a consistent pattern: hydropower output is primarily determined by river size, elevation change, and sustained federal investment in dam infrastructure, rather than by state size or population. Washington leads due to the Columbia River’s combination of high flow and significant elevation drop, a trend also observed in New York’s Niagara River, Idaho’s Snake River, and South Dakota’s Missouri River. The principal conclusion is that hydropower capacity is largely shaped by geographic features established decades ago and subsequently enhanced through engineering.

This accounts for the enduring stability of hydropower rankings, with states such as Washington, California, Oregon, New York, and Alabama consistently occupying leading positions. For those comparing clean energy sources across states, hydropower rankings display greater stability than most other forms of energy generation. Many households continue to receive electricity from dams constructed generations ago, which remain both operational and effective.