Hydropower uses the movement of water to generate electricity, and it’s been doing it at scale for over a century. Today, it remains one of the most established forms of renewable energy, supplying millions of homes and businesses with reliable power.
In the U.S., hydropower plays a steady, behind-the-scenes role in balancing the grid. It doesn’t make as many headlines as solar or wind, but it’s a major contributor to the clean energy mix.
If you’re thinking about a career in renewable energy, it’s worth knowing where hydropower excels and where it faces challenges. That perspective can shape wise choices about where to focus your skills.
What Is Hydropower?
Hydropower, or hydroelectric power, generates electricity by converting the momentum of falling or fast-moving water.
There are three main types of hydropower, named for how the water moves.
- Run-of-river: Also known as diversion hydropower, it uses a river’s natural flow and elevation drop to generate electricity without any significant water storage. There are no dams, and the river’s running water drives turbines.
- Reservoir or dam: These are impoundment facilities and the most common hydroelectric power plants. In an extensive hydropower system, dams create reservoirs that store water for later use.
When water is released from the reservoir, its force spins the turbines, activating a generator to create electricity.
- Pumped storage: Pumped storage or PSH works like a giant battery. The facility stores electricity from another renewable source, like wind, for later use by pumping water from a lower reservoir to a higher elevation reservoir.
When electricity is needed, the water is pumped back to the reservoir at the lower elevation, turning the turbines.
What Are the Advantages of Hydropower?
Hydropower has earned its long-standing place in the energy mix for a reason. It’s a reliable and efficient energy source built for long-term use.
Unlike solar or wind, it doesn’t depend on daily weather, and once a plant is running, the emissions are close to zero. It can also be tailored to the area where the plant is located rather than relying on a one-size-fits-all situation.
From storage flexibility to local economic benefits, here are the advantages of choosing hydropower as a strong choice for energy production.
Reliable Energy Supply
Unlike solar and wind, hydropower has a consistent base-load power. As a renewable, it doesn’t require sunny or windy conditions to be useful. Hydroelectric power is a reliable energy source provided the water is available and the equipment is running.
That means that hydropower is useful for grid stability and peak demand, capable of providing electricity when the supply is low from other sources.
It can also be used to supplement existing power supplies when peak demand is high, rather than relying on energy stored in batteries.
Low Operational Emissions
Hydropower has very low operational greenhouse gas (GHG) emissions, especially compared to fossil fuels.
The carbon footprint that hydropower has is relatively low and consists of emissions from the construction of a dam, the formation of the reservoir, and the materials used in the plant’s construction.
Reservoirs can give off methane and carbon dioxide, but these emissions are low and can be managed by adding aeration devices or changing water intake locations.
Once the plant is built, there is no direct air pollution.
Run-of-the-river systems are considered the most environmentally friendly as they don’t require flooding large areas. Nature is used mostly without changing it.
With a carbon footprint roughly the same as wind power plants, hydropower can also displace power generation sources like fossil fuels that create much higher emissions.
Long Facility Lifespan
Hydropower plants have an extremely long lifespan, often operating for 50 to over 100 years with proper maintenance. In contrast, many power generation plants only last between 20 to 30 years before having to be replaced.
With regular maintenance and improvements, hydropower facilities can be extended indefinitely. This makes them an excellent long-term infrastructure investment and allows costs to be spread out over time.
Storage and Flexibility (Pumped Storage)
One of the three types of hydropower is pumped storage, where the reservoir acts like a battery, storing energy to be released on demand. It has a larger storage capacity than batteries and a longer storage duration.
It’s also more flexible because pumped storage plants can quickly switch between pumping and generating depending on grid fluctuations.
Storing more energy for a longer period is important for supporting intermittent renewables. Hydropower can be paired with solar or wind energy, and it will pick up where they leave off or supplement their power generation during peak demand.
Local Economic Impact
The economic impact of a hydropower plant on local communities is mostly positive.
- Jobs are created during construction and operation
- Local economies are boosted, especially if electricity revenues are shared with them
- Revenue increases for municipalities through licensing and water use agreements
- Reservoirs can provide areas for fishing, boating, and attract tourism
- Can provide an affordable energy source that benefits the community
Flood Control and Water Management
Thanks to their reservoirs, hydropower plants help manage seasonal water flows by providing flood control and water management services.
In areas known for flooding during the rainy season, this water management can protect agricultural sites from having their crop land flooded.
A carefully placed dam and hydropower system can protect urban areas from destructive amounts of water that might overwhelm sewer systems.
What Are the Disadvantages of Hydropower?
For all its strengths, hydropower has downsides that need to be addressed. Some are environmental, while others are economic.
Building a dam or reservoir is expensive, and it can disrupt entire ecosystems and local communities. Even once a plant is running, drought or climate shifts can limit how much power it actually produces.
These drawbacks don’t cancel out the benefits, but they matter if you plan to work in this space.
Environmental Disruption
When hydropower facilities are built, there are always disruptions to the surrounding nature. Even run-of-the-river systems, which work the most naturally of the three types, still impact the environment around them.
Dams can affect animal habitats, displacing them or affecting the availability of their food source, or changing downstream systems.
Although not every hydropower plant affects the local ecosystem to the same degree, construction can affect fish migration, the water quality, which in turn affects marine life, and the flow of sediment.
High Upfront Costs
Construction of a hydroelectric facility is expensive and time-intensive.
Micro-hydropower costs can be up to $2,500 per kW of installed capacity, whereas large-scale production costs can run up to $19,000 per kW.
These costs can increase if civil works must be involved to increase the water pressure or if there are other factors like complexity or environmental regulations.
Some of these costs are lessened due to the overall longevity of the facilities, but financing often requires a public-private partnership to cover all the costs.
Geographic Limitations
Not every region has the right topography for a small hydropower system, let alone a large-scale operation.
Site selection is limited by water availability and elevation, and local regulations that may prohibit the construction of dams in areas where wildlife may be negatively affected.
Community and Cultural Impacts
One of the biggest disadvantages of hydropower is its impact on communities and cultures in the area surrounding construction. This impact is especially true of Indigenous communities, who face a disproportionate impact.
Reservoirs can displace local populations, implement changes in their traditional livelihoods, and disrupt cultural practices.
Changes to the landscape and access to water may reduce the ability to farm and begin to destroy green spaces and sacred sites on ancestral lands.
Drought Risk and Climate Volatility
One of the advantages of hydropower is its capacity for drought mitigation. However, long dry periods can reduce power output, and climate change increases the frequency and severity of extreme drought and flood periods.
When water levels are drastically reduced, it can lead to energy shortages, rationing, and blackouts.
These droughts are less predictable in water-scarce regions and may force a hydroelectric dam to supplement its production using fossil fuels.
Where Hydropower Fits in the U.S. Energy Mix
Hydropower plays an impressive role in the U.S. energy mix, accounting for 27% of total utility-scale renewable electricity generation and almost 6% of U.S. utility-scale electricity generation.
Until recently, it accounted for the largest share of renewable energy until 2024, when solar slipped ahead.
Nearly all states have conventional hydroelectric facilities, but most hydroelectricity is produced at large dams built by the federal government.
The biggest sector for hydropower is the western states, concentrated in Washington, California, and Oregon. Washington has more capacity to generate hydroelectricity than any other state and is the site of the Grand Coulee Dam, the largest U.S. facility with the highest capacity.
Jobs in Hydropower: Where the Work Is
Hydropower projects need a wide range of professionals, including engineers, operators, technicians, and environmental specialists.
Civil and mechanical engineers work on dam structures and turbine systems. Technicians monitor equipment, handle maintenance, and ensure systems stay efficient. Environmental roles focus on water quality, habitat impact, and regulatory compliance.
You’ll find jobs with public utilities, federal agencies, and private energy firms. As older plants are modernized and new ones are proposed, demand is rising for workers who understand traditional systems and newer digital controls.
Conclusion
Hydropower offers stability, reliability, and long-term value but comes with trade-offs. For job seekers, it’s a field with steady demand, especially as older plants upgrade.
If you’re looking for hands-on work with impact, hydropower remains a key part of the energy transition and a solid place to build experience. If it’s not your field, continue reading about other renewable energy careers available.