Hydropower is used on every inhabited continent, generating about 14% of the world’s electricity. It remains the single largest source of low-carbon power globally, producing roughly 4,210 terawatt-hours in 2023. From massive dams spanning major rivers in China and Brazil to small turbines powering villages in rural Africa, hydropower shows up in remarkably different forms depending on the geography and energy needs of a region.
Countries That Rely on It Most
China dominates global hydropower. The Three Gorges Dam on the Yangtze River holds the title of the world’s largest power plant of any kind, with a capacity of 22.5 gigawatts. That single facility can generate enough electricity to power millions of homes. China is also projected to account for 40% of all new hydropower capacity through 2030, cementing its position as the leading market.
Brazil and Paraguay share the Itaipu Dam on the Paraná River, the world’s second-largest hydroelectric facility at 14 gigawatts. Itaipu supplies a substantial portion of Paraguay’s total electricity and a significant share of Brazil’s. Other major hydropower nations include Canada, the United States, Russia, India, and Norway. Russia’s Sayano-Shushenskaya Dam on the Yenisei River, with 6.4 gigawatts of capacity, is the country’s largest power plant. Norway is notable because nearly all of its electricity comes from hydropower, thanks to its steep terrain and abundant rainfall.
Nine of the world’s ten largest operating power plants are hydroelectric, which reflects how well suited large river systems are for high-capacity generation.
How It’s Used in the United States
The United States has a long history with hydropower, concentrated heavily in the Pacific Northwest and the western mountain states. The Grand Coulee Dam on the Columbia River in Washington is the largest dam in the country and the seventh-largest power plant in the world. States like Washington, Oregon, and Idaho get a large share of their electricity from river systems fed by mountain snowpack.
Beyond the West, hydropower facilities operate across the Southeast (particularly along the Tennessee River system), the Northeast, and parts of the Great Plains. The U.S. also has a growing number of pumped storage facilities, which store energy by moving water between upper and lower reservoirs. These plants don’t generate new electricity so much as they store and release it when demand spikes.
Large Dams vs. Small River Systems
Not all hydropower looks the same. The type of facility depends on local geography, population density, and how developed the electrical grid is.
Reservoir-based dams are the most familiar type. A large dam holds back a river to create a reservoir, and water is released through turbines on a controlled schedule. These facilities can store months’ worth of water and adjust output to match demand. They account for about half of all new hydropower capacity expected through 2030. The tradeoff is that they require massive river systems and flood large areas of land.
Run-of-river systems are smaller and work differently. Instead of storing water behind a dam, they divert part of a river’s natural flow through a turbine and return it downstream. These are common in areas without large grids or the infrastructure to support a major dam. A run-of-river facility on the Tazimina River in rural Alaska, about 175 miles southwest of Anchorage, is one example. In developing countries, particularly in sub-Saharan Africa and South Asia, this approach is gaining traction because it’s cheaper to build and less disruptive to the environment.
Rural Electrification in Developing Regions
Micro-hydropower systems, typically generating less than 100 kilowatts, are being deployed in rural communities across Africa, South Asia, and Latin America. In Taraba state, Nigeria, feasibility studies have examined micro-hydro plants along the Taraba River to serve smallholder farmers in communities like Wurno-Gassol. A project in Thima, Kenya has demonstrated that small-scale hydropower is economically viable for off-grid communities.
These projects matter because roughly 600 million people in sub-Saharan Africa lack access to electricity. Micro-hydro fills a gap that large grid infrastructure can’t easily reach. The turbines are relatively simple, the fuel (flowing water) is free, and ongoing maintenance costs are low compared to diesel generators. In countries like India and China, there’s still significant untapped potential for both small and large hydropower development.
Pumped Storage for Grid Stability
As wind and solar power grow, so does the need for energy storage. On calm or cloudy days, something has to fill the gap. Pumped storage hydropower handles this better and more cheaply than any alternative at scale. It accounts for 97% of all electricity storage worldwide.
The concept is straightforward: when electricity supply exceeds demand (say, on a sunny afternoon with strong solar output), surplus power pumps water uphill to an upper reservoir. When demand rises or renewables drop off, that water flows back down through turbines to generate electricity. Pumped storage represents about 30% of all new hydropower capacity expected through 2030. It’s a mature, off-the-shelf technology, and researchers at the Australian National University have mapped thousands of potential sites globally that could support new facilities.
Hybrid Solar-Hydro Facilities
A newer trend pairs floating solar panels with existing hydroelectric reservoirs. The world’s largest hydro-solar plant began operation in China’s Yalong River Basin, where the Kela photovoltaic station covers more than 16 million square meters at high altitude and connects to the Lianghekou hydropower station via a 500-kilovolt transmission line. Its installed solar capacity alone reaches 1,000 megawatts.
Similar projects are appearing elsewhere. In Colombia, a 1.5-megawatt floating solar array called Aquasol sits on the reservoir at the 340-megawatt Urrá hydropower plant, testing whether floating panels can boost energy reliability at dams with fluctuating water levels. In France, EDF opened the Lazer floating solar plant with over 50,000 panels on a dam reservoir, doubling that site’s renewable output. These hybrids make sense because dam reservoirs already exist, the water keeps panels cool (improving efficiency), and both sources share the same grid connection.
Global Growth Outlook
Global hydropower capacity is expected to grow by about 17%, or 230 gigawatts, between 2021 and 2030. That’s significant, but the pace is actually slowing. Net capacity additions over this period are forecast to be 23% lower than the previous decade, largely because the easiest and most productive dam sites in developed countries have already been built.
The growth that does happen will be concentrated in developing nations. China leads, but India, parts of Southeast Asia, Africa, and Latin America all have major untapped river systems. The International Energy Agency estimates that with the right policy support, global additions could be 40% higher than current forecasts. The barriers aren’t technological. They’re regulatory delays, financing challenges, and environmental review processes that can stretch project timelines to a decade or more.