Real‑world examples of hydropower projects: impact & benefits

If you want to understand hydropower, you don’t start with definitions—you start with dams, rivers, and communities already living with them. Some of the best examples of hydropower projects: impact & benefits show how one river can power millions of homes, reshape a region’s economy, and dramatically cut carbon emissions.

Hydropower currently provides about 16% of global electricity and around 60% of all renewable power worldwide, according to the International Energy Agency (IEA) (iea.org). In the United States, the U.S. Energy Information Administration (EIA) reports that hydropower made up about 6% of total electricity generation and 28% of renewable generation in 2023 (eia.gov). Those aren’t just abstract numbers—they’re grounded in specific projects.

Below are real examples of hydropower projects: impact & benefits across different continents and scales, followed by a clear breakdown of environmental, social, and economic outcomes.

Large‑scale examples of hydropower projects: impact & benefits

Three Gorges Dam, China – Gigawatts of power, massive trade‑offs

The Three Gorges Dam on the Yangtze River is one of the best‑known examples of a hydropower project with outsized impact.

• Capacity: About 22.5 gigawatts (GW)
• Generation: Roughly 100+ terawatt‑hours (TWh) per year in recent years
• Impact: Supplies electricity to tens of millions of people and significantly reduces coal use

From a climate perspective, this is a textbook example of hydropower projects: impact & benefits. Replacing coal generation with Three Gorges output avoids an estimated 80–100 million metric tons of CO₂ per year, depending on the comparison baseline.

But the social and ecological costs are heavy:

• Over 1 million people were relocated
• Historic and cultural sites were submerged
• Sediment flow and fish migration patterns in the Yangtze were disrupted

Three Gorges is a reminder that even the best examples of large hydropower projects come with long‑term environmental and social consequences that have to be managed—not ignored.

Itaipu Dam, Brazil–Paraguay – A binational clean power backbone

The Itaipu Dam on the Paraná River is another classic example of hydropower projects: impact & benefits at scale.

• Capacity: 14 GW
• Generation: Around 70–80 TWh per year
• Role: Provides roughly 10–15% of Brazil’s electricity and about 80–90% of Paraguay’s in many years

For Paraguay, Itaipu is not just one example of a hydropower project—it is the backbone of the entire power system. The benefits include:

• Very low‑carbon electricity for an entire country
• Stable, relatively low‑cost power for industry and households
• Long‑term binational cooperation and power trade

The downsides are familiar: habitat loss, displacement of communities, and changes to river ecosystems. But in terms of climate and energy security, Itaipu remains one of the best examples of hydropower projects: impact & benefits on a national scale.

Grand Coulee Dam, United States – Power plus irrigation in the Pacific Northwest

The Grand Coulee Dam on the Columbia River in Washington State is a classic U.S. example of hydropower projects: impact & benefits that go beyond electricity.

• Capacity: About 6.8 GW
• Generation: Often around 20 TWh per year
• Built: 1940s, expanded later

Hydropower here supports:

• Large‑scale irrigation for agriculture in Central Washington
• Low‑carbon electricity for the Pacific Northwest
• Integration with other renewables like wind in the region

The Columbia River system also highlights long‑running conflicts with salmon populations, tribal treaty rights, and river health. The ongoing work to improve fish passage and restore habitat is a real‑time case study in how older hydropower projects are being upgraded to reduce harm while keeping the benefits.

For more context on U.S. hydropower’s role in the grid and environment, the U.S. Department of Energy’s Water Power Technologies Office provides detailed reports and data (energy.gov).

Regional and mid‑scale examples include flexible, modern designs

Not all hydropower is mega‑dam territory. Some of the most interesting recent examples of hydropower projects: impact & benefits are mid‑scale or run‑of‑river designs that aim to reduce flooding and ecological disruption.

Hoover Dam, United States – Hydropower under climate pressure

The Hoover Dam on the Colorado River is one of the most famous hydropower projects in the world.

• Capacity: About 2 GW
• Generation: Historically around 4 TWh per year, but declining as water levels drop

Hoover is a strong example of hydropower projects: impact & benefits and also hydropower’s vulnerabilities. It provides:

• Low‑carbon electricity to Nevada, Arizona, and California
• Flood control and water storage for the Southwest
• Recreational and tourism benefits

But prolonged drought and climate‑driven shifts in snowpack in the Colorado River Basin have lowered Lake Mead to historically low levels in recent years, cutting power output. This is a very real example of how climate change can directly affect hydropower reliability.

Run‑of‑river projects in Canada and the Pacific Northwest

Run‑of‑river plants, which divert a portion of river flow through turbines without creating huge reservoirs, are increasingly promoted as lower‑impact options. In British Columbia and the U.S. Pacific Northwest, dozens of small to mid‑scale run‑of‑river projects feed into regional grids.

These examples of hydropower projects: impact & benefits show:

• Lower land inundation compared with large dams
• Reduced methane emissions from reservoirs
• Faster permitting and construction timelines in some cases

The trade‑offs: they can still affect fish, sediment, and river flow timing, and they usually lack the big storage reservoirs that make traditional dams so valuable for grid flexibility.

Small‑scale and community hydropower: local impact, big benefits

Micro‑hydro in Nepal and the Himalayas

In rural Nepal and other Himalayan regions, micro‑hydro systems (often under 100 kilowatts) have brought first‑time electricity access to thousands of households. These systems are some of the best examples of hydropower projects: impact & benefits at the community level.

Impact and benefits include:

• Replacing kerosene lamps and diesel generators
• Supporting local businesses (mills, workshops, refrigeration)
• Enabling lighting for schools and clinics

These real examples of hydropower projects: impact & benefits show how small systems can be tailored to local rivers, managed by communities, and maintained with relatively simple technology.

Small hydropower in the United States and Europe

In the U.S., the Department of Energy has identified tens of gigawatts of potential capacity at existing non‑powered dams—structures that already exist for navigation, flood control, or water supply but don’t yet generate electricity. Adding turbines to these sites is one of the most promising examples of hydropower projects: impact & benefits with minimal new ecological disruption.

In Europe, small hydropower on existing weirs, canals, and old mill sites has become a quiet but meaningful contributor to local grids. These projects often:

• Use existing infrastructure
• Provide distributed generation close to where power is used
• Avoid the large reservoirs that cause the most environmental concern

Pumped storage hydropower: the grid’s giant battery

If you’re looking for an example of hydropower projects: impact & benefits for grid reliability, pumped storage is it.

Pumped storage hydropower (PSH) uses two reservoirs at different elevations. When electricity is cheap or abundant (for example, during midday solar peaks), water is pumped uphill. When electricity is needed, water is released back down through turbines to generate power.

Bath County Pumped Storage Station, United States

The Bath County Pumped Storage Station in Virginia, often called the “world’s largest battery,” is a standout example.

• Capacity: Around 3 GW of generating capacity
• Function: Stores energy and provides rapid response to grid fluctuations

This project shows how hydropower can:

• Balance variable wind and solar
• Provide fast ramping to stabilize frequency
• Reduce the need for fossil‑fuel peaker plants

The U.S. Department of Energy highlights pumped storage as a key tool for integrating high levels of renewables into the grid (energy.gov). If you’re thinking about the future of clean energy, these examples of hydropower projects: impact & benefits are less about raw generation and more about storage and flexibility.

Environmental and social impacts: the full picture

Hydropower is low‑carbon, but it is not impact‑free. Real examples of hydropower projects: impact & benefits always come with trade‑offs, and ignoring them is a mistake.

Climate and air quality benefits

Compared with coal or natural gas plants, hydropower typically has very low lifecycle greenhouse gas emissions, especially in colder climates and in projects with smaller reservoirs. Analyses compiled by the U.S. National Renewable Energy Laboratory (NREL) and IPCC consistently show hydropower emissions well below fossil fuels on a grams‑CO₂‑per‑kWh basis.

Benefits include:

• Avoided CO₂ emissions
• Reduced sulfur dioxide, nitrogen oxides, and particulate pollution
• Less dependence on imported fossil fuels

These are some of the strongest reasons policymakers keep pointing to examples of hydropower projects: impact & benefits when designing decarbonization plans.

Ecological and social costs

On the other side of the ledger:

• Reservoirs flood large areas, destroying terrestrial habitats and altering local microclimates.
• Fish migration is blocked or disrupted, affecting entire river ecosystems.
• Sediment trapping behind dams changes river morphology downstream and can accelerate coastal erosion.
• Communities—often Indigenous and rural—are displaced, losing land, livelihoods, and cultural sites.

Studies published by organizations such as the World Bank and International Union for Conservation of Nature (IUCN) have documented these impacts across multiple continents. The lesson from decades of experience: even the best examples of hydropower projects must be planned with rigorous environmental review, social safeguards, and long‑term monitoring.

Methane from reservoirs

In tropical regions, reservoirs can emit methane as submerged vegetation decomposes. This can partly offset climate benefits if not carefully managed. Modern project design increasingly includes:

• Clearing vegetation before filling reservoirs
• Operating reservoirs to reduce conditions that favor methane formation

Again, real examples of hydropower projects: impact & benefits in Brazil, Southeast Asia, and Africa are pushing engineers and policymakers to refine how reservoirs are designed and managed.

Economic and grid benefits: why hydropower still matters in 2024–2025

Hydropower remains one of the most cost‑effective forms of low‑carbon electricity over a project’s lifetime. The IEA and International Renewable Energy Agency (IRENA) consistently rank hydropower among the lowest‑cost renewables on a levelized cost basis once built, especially for large plants.

Key economic and grid benefits include:

• Long asset life: Many dams operate for 50–100 years with upgrades.
• Fast response: Turbines can ramp up or down in minutes, supporting grid stability.
• Storage: Reservoirs and pumped storage act as energy storage, backing up solar and wind.
• Local jobs and infrastructure: Large projects create construction jobs and often bring roads, bridges, and communication infrastructure to remote areas.

In the U.S., the EIA and DOE both highlight hydropower as a foundational part of a low‑carbon grid, especially when paired with new solar and wind.

Future trends: where new examples of hydropower projects are heading

Hydropower is not expanding at the breakneck pace of solar and wind, but it is evolving.

Trends to watch in 2024–2025 and beyond:

• Modernization of existing dams: Upgrading turbines, controls, and fish passage at older projects can increase output and reduce harm without new dams.
• Non‑powered dams: Adding generation to existing structures in the U.S. and Europe is one of the cleanest ways to grow hydropower.
• Hybrid plants: Pairing hydropower with floating solar on reservoirs to boost output and reduce evaporation.
• Environmental flow management: Using data and modeling to mimic more natural river flows while still generating power.

New examples of hydropower projects: impact & benefits are likely to look less like Three Gorges and more like smarter, upgraded, and better‑managed systems built on infrastructure we already have.

FAQ: examples of hydropower projects, impact, and trade‑offs

Q1. What are some well‑known examples of hydropower projects: impact & benefits?
Some of the best‑known examples include the Three Gorges Dam (China), Itaipu Dam (Brazil–Paraguay), Grand Coulee Dam and Hoover Dam (United States), and the Bath County Pumped Storage Station (United States). These projects show how hydropower can provide massive amounts of low‑carbon electricity, support irrigation and water supply, and stabilize power grids.

Q2. Can you give an example of a small hydropower project with community benefits?
Micro‑hydro systems in rural Nepal are a strong example of small hydropower projects: impact & benefits. They provide first‑time electricity access, replace diesel and kerosene, and support local businesses and schools, all with relatively modest environmental footprints compared with large dams.

Q3. Are there examples of hydropower projects that caused serious environmental damage?
Yes. Many large dams built in the 20th century, such as some projects on the Mekong, Amazon, and Yangtze rivers, have flooded vast areas, displaced communities, and disrupted fish migration. These examples of hydropower projects have pushed regulators and developers to adopt stricter environmental and social standards.

Q4. How do pumped storage projects fit into clean energy plans?
Pumped storage projects like Bath County are prime examples of hydropower projects: impact & benefits for grid stability. They act like large batteries, storing energy when supply is high and releasing it when demand spikes. This makes it easier to integrate variable renewables like wind and solar.

Q5. Are new hydropower projects still being built, or is the focus mostly on upgrades?
Both. In many developed countries, the focus is shifting toward modernizing existing dams and adding generation to non‑powered dams. In parts of Asia, Africa, and Latin America, new dams are still being proposed and built. The best examples of modern hydropower projects aim to balance impact & benefits by using better planning, environmental safeguards, and community engagement.

Hydropower is not perfect, but real examples of hydropower projects: impact & benefits show why it remains a cornerstone of many clean energy strategies. The challenge for the next few decades is clear: keep the climate and grid advantages, while dramatically improving how we handle the environmental and social costs.