What Do Hydropower Companies Do?

What do hydropower companies do?

Hydropower is a form of renewable energy that harnesses the power of flowing water to generate electricity. Hydropower companies build and operate hydroelectric dams and power plants that use water’s natural movement to turn turbines and generate power. A hydropower facility captures flowing water in a reservoir behind a dam to control its release. The moving water spins turbines connected to generators to convert the water’s energy into electricity.

Hydropower companies develop, construct, and maintain hydropower projects and facilities. They are involved in all aspects of hydropower generation, from identifying suitable dam and reservoir sites, obtaining permits, financing and overseeing construction, operating and maintaining power plants, and distributing the generated electricity. Major tasks include reservoir operations, turbine maintenance, environmental mitigation, compliance, safety management, and more. Larger companies may own multiple hydropower plants and distribution infrastructure to deliver electricity to homes and businesses.

Some of the largest hydropower companies worldwide include Hydro-Québec, Voith Hydro, China Yangtze Power Co., RusHydro, and China Three Gorges Corporation. The hydropower industry continues to grow as companies develop new projects, upgrade existing infrastructure, and integrate storage and pumped storage capabilities.


While hydropower technology has been used for thousands of years in various forms, its commercialization began in the late 19th century. According to History – National Hydropower Association, industries in the United States first began harnessing the power of waterfalls in the late 1800s to operate machinery. One of the first hydroelectric power plants was built at Niagara Falls in 1879 by P.G. Curtis.

By the early 20th century, hydropower was being widely used to generate electricity. Major dam projects like the Hoover Dam, Grand Coulee Dam and others were built in the 1930s and 1940s as part of government infrastructure programs, greatly expanding hydropower capacity in the US. History of Hydropower – Department of Energy notes that by 1940, hydropower accounted for 40% of US electrical generation.

So while primitive hydropower applications date back thousands of years, it emerged as a major commercial electricity source in the late 19th and early 20th centuries with the advent of hydropower turbines and large dam projects.

Generating Power

Hydropower plants generate electricity by harnessing the power of moving water. Typically, dams are constructed to create reservoirs that control water flow. The dam stores potential energy by holding back the water in the reservoir. When the water is released, it flows through a pipe called a penstock towards the turbines. As the water moves through the penstock, it gains kinetic energy which turns the blades of the turbine. The mechanical energy from the spinning turbine then rotates a generator to produce electricity (1).

There are several components involved in hydropower generation. The dam serves to control water flow and provide hydraulic head, which refers to the pressure created by the height of the water behind the dam. The taller the dam, the more hydraulic head it can provide. The turbines convert the kinetic energy of the moving water into mechanical energy. Common types of turbines used include impulse, reaction, and gravity turbines. The generator then converts the mechanical rotation into electrical energy (2).

By constructing dams and reservoirs, hydropower plants can effectively harness the potential energy in water as it flows downstream and convert this into electricity. The reservoir not only stores water but also helps regulate electricity production by providing water when it is most needed (1).


(1) https://www.energy.gov/eere/water/how-hydropower-works

(2) https://www.eia.gov/energyexplained/hydropower/


Once the power is generated at the hydroelectric dam, it needs to be transported long distances to reach homes and businesses. Hydropower companies build transmission lines to carry the electricity from the power plant to substations and eventually the end users.

Most hydropower plants are located far away from cities and towns, so the electricity must be transported over long distances along transmission lines. According to the Department of Energy, “The energy must flow along transmission lines, sometimes hundreds of miles from its source” (https://www.penlight.org/hydropower-101-transmission-from-dam-to-doorstep/).

Transmission lines, transformers, switches, and other infrastructure are built and maintained by the hydropower companies. High voltage transmission allows for more efficient transfer over long distances. The transmission system ultimately connects to distribution lines that deliver power directly to homes, business, factories, and other end users.


Regular maintenance is crucial for hydropower companies to ensure their facilities continue operating efficiently and safely. Some key maintenance tasks include:

Inspecting and servicing dams to monitor their structural integrity and repair any issues like cracks or leaks. Visual inspections, sensor systems, and underwater inspections help identify potential problems.

Maintaining turbines by cleaning, inspecting, and lubricating parts like bearings, as well as testing and calibrating sensors and controls. Turbines may need to be overhauled or refurbished over time.

Servicing generators by checking and replacing worn parts like brushes, bearings, cooling systems, and insulation. Testing protective relays and automation systems is also critical.

Hydropower companies need to balance maintenance needs with power generation demands. Careful planning allows taking units offline for maintenance while meeting electricity supply obligations.

Environmental Impact

While hydropower is a renewable energy source, hydroelectric dams can have major environmental impacts by changing the environment and affecting land use, homes, and natural habitats (source). Building a dam floods large areas of land upstream, altering ecosystems and displacing wildlife and human populations. Downstream, the dam alters water quality, temperature, and flow levels. These changes affect native plants and animals that have adapted to the natural flow of the river (source).

Specifically, constructing reservoirs floods forests, wetlands, and wildlife habitats. Valuable agricultural land and sites with cultural significance can also be inundated. The flooded land creates a barrier for plant and animal movement and migration. Additionally, reservoirs produce greenhouse gases as flooded vegetation decays underwater (source).

Downstream, dams change water flow levels, temperatures, and oxygen levels, harming fish and other aquatic species. Some fish can no longer reach upstream spawning areas due to the barrier created by the dam. Others cannot survive in the slower water and different habitat of the reservoir. Reduced river flows downstream can also negatively impact floodplain forests and wetlands that rely on annual flood cycles.


The hydropower industry employs thousands of workers in various roles. According to a Statista report, there were around 6,840 employees working in hydroelectric power generation in the United States in 2021. The Department of Energy estimates the total hydropower workforce is around 72,415, with jobs in construction, operations, engineering, and other areas.

Major jobs associated with hydropower projects include civil engineers, construction workers, electricians, technicians, operators, and maintenance personnel. Civil engineers design and oversee dam construction. Construction workers build the dams, tunnels, and other infrastructure. Electricians and technicians install and maintain the turbines, generators, transformers, and transmission lines. Operators monitor and control equipment from dam control centers. Maintenance crews inspect and service equipment to keep it running safely and efficiently.

Given the complex nature of hydropower systems, they require a range of skilled professionals. Workers need expertise in areas like hydrology, structural engineering, hydraulics, electricity, and mechanical equipment. With growth in the industry, there is increased demand for a qualified, diverse workforce in the coming years.


Working in hydropower plants comes with inherent risks and hazards that companies must address to protect workers and the public. Two major safety concerns are dam failure and workplace accidents.

According to the FERC’s “Guidelines for Public Safety at Hydropower Projects”, dam failures can release massive torrents of water downstream, posing a catastrophic threat. Companies undertake extensive dam safety programs, including structural integrity monitoring, spillway capacity checks, emergency planning, and public education. Advanced sensor networks and remote operational controls help mitigate risks.

Within hydropower facilities, hazards include working at height, energized equipment, confined spaces, and rotating machinery. Companies implement safety management systems, perform hazard analysis, provide protective equipment, and conduct employee training. Strategies like “safety in design” help eliminate dangers through planning and engineering controls before construction. A culture of safety, group accountability, and individual responsibility is also critical.


Hydropower in the United States is regulated at the federal level by the Federal Energy Regulatory Commission (FERC). FERC issues licenses and inspects non-federal hydropower projects. According to FERC, “the Commission issues licenses for terms ranging from 30 to 50 years to construct, operate and maintain nonfederal hydropower projects. The Commission bases its licensing decisions on economic, environmental, and developmental considerations.”

Hydropower companies must apply for licenses from FERC and go through an extensive process that involves submitting detailed plans, allowing opportunities for public input, consulting with agencies, and completing environmental assessments. FERC conducts inspections of hydropower projects to ensure compliance with license terms and conditions. Inspectors examine project structures, review operations and maintenance records, and verify that license requirements are being followed. FERC has the authority to take compliance action if violations are found.

In addition to federal oversight from FERC, hydropower projects must comply with regulations from other government agencies like the Environmental Protection Agency, Army Corps of Engineers, Fish and Wildlife Service, National Marine Fisheries Service, and state agencies. Obtaining all necessary approvals and maintaining compliance throughout the life of a hydropower project involves extensive government oversight and regulation.



Future Outlook

The future looks bright for continued growth and innovation in hydropower. According to the U.S. Department of Energy’s Hydropower Vision report, U.S. hydropower capacity could grow from 101 gigawatts to nearly 150 gigawatts by 2050. This growth will come from upgrading existing infrastructure as well as developing new low-impact hydropower at existing dams and conduits.

New technologies are also expanding hydropower capabilities. Advances in hydropower turbines, drivetrains, and other components are enabling greater efficiency and flexibility. Pumped storage hydropower can store excess renewable energy and release it when needed. Floating solar panels on hydropower reservoirs can supplement generation. With these innovations, hydropower is poised to play an integral role in the renewable energy system of the future.

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