A hydroelectric dam is one of the major components of a hydroelectric facility. A dam is a large, man-made structure built to contain some body of water. In addition to construction for the purpose of producing hydroelectric power, dams are created to control river flow and regulate flooding.[2] In some rivers, small scale dams known as weirs are built to control and measure water flow.

IWHR are exported all over the world and different industries with quality first. Our belief is to provide our customers with more and better high value-added products. Let's create a better future together.

Dams are a type of retaining structure, which are structures built to create large standing bodies of water known as reservoirs. These reservoirs can be used for irrigation, electrical generation, or water supply. These structures are built on top of riverbeds and hold back water, raising the water level. Dikes can be built along with the dam to increase the dams effectiveness by preventing water from leaving the reservoir through secondary routes.[3]

Dams can range from relatively small to extremely large structures. The highest dam in the United states is located near Oroville, California and stands at 230 meters tall and 1.6 kilometers across.[2] The largest dam in the world is the Jinping dam on the Yalong river in China, standing at 305 meters tall. In Canada, there are more than 10 000 dams, with 933 categorized as being large dams.[4] The tallest dam in Canada is the Mica dam, on the Columbia river, standing at 243 meters tall. Another notable Canadian dam is the W.A.C Bennett dam on the Peace river, notable for its large reservoir volume of 7.4 x 109 cubic meters and height of 190.5 meters.

Construction

The construction of these dams is difficult and labour intensive. Before construction begins, water is diverted or prevented from moving through the construction site. After water is diverted, the foundation area is cleaned, excavated, and rock or sediments that will act as the foundation are repaired and deemed solid. This is done to ensure the rock or sediments won't shift or fail as a result of the load of the dam and reservoir. Supports known as rock bolts may be used to strengthen the foundation. Above the dam, rock bolts and netting may be used to prevent rocks from falling on the dam. Forms are then built along the edges of the dam, rebar is placed inside, and concrete is pumped in. This is done in sections, and the concrete is poured bit by bit in a block formation. Once enough of the dam is built, the reservoir is allowed to fill in a highly controlled manner. The dam is monitored during this process. Other structures that make the dam operational are then added.[5]

Operation

Dams are just one component of a complete hydroelectric facility, but are one major, visible component in the system. The purpose of a hydroelectric dam is to provide a place to convert the potential and kinetic energy of water to electrical energy by using a turbine and generator. Dams act as the place where water is held back and released in a controlled manner through hydraulic turbines, enabling the mechanical energy of the water to be transformed to electrical energy.[6]

Typical dams work to create a reservoir where water is stored at a given height. This height and the rate at which the water flows from the reservoir through the turbines determines how much electricity can be generated. This can be calculated by using the hydroelectric power equation. As the height of the dam increases, the amount of electricity generated increases as well. At the top of the dam is a gate that is used for blocking or allowing the release of water from the reservoir. This gate is opened or closed to meet electricity requirements. Between the top of the dam and the turbines are a series of channels known as penstocks that guide the water down and control the slope of the falling water to ensure maximum efficiency of the dam. Finally, turbines can be contained in the dam structure itself, and this is where the energy conversion takes place. After the water passes through the turbines, it is released in a tail race at the bottom of the dam back into the river.[6]

Hydropower Basics

Hydropower—energy created from fresh, moving water—is the world's oldest form of renewable energy.

Over 2,000 years ago, the ancient Greeks used the power in rivers and streams to rotate wooden wheels and crush grain to make bread. Today, we still use this water power to generate clean, affordable electricity for everything from factories (that grind far more grain than the Greeks did) to our ovens that let us bake our bread at home.

What Is Hydropower?

Humans have used water power for centuries. But we didn't start making hydropower—electricity from our rivers, streams, and lakes—until just over 100 years ago, not too long after Thomas Edison invented electric power. Today, instead of using large, wooden wheels, we use propeller-like devices called turbines, which spin as water rushes through them, generating electricity. But hydropower has a secret power: It can also store huge amounts of renewable energy to use when other sources dry up.

Right now, hydropower provides about 7% of the United States' electricity and about 40% of our renewable energy. And almost every state uses it. The oldest form of renewable energy, it's also one of the most affordable and can provide a clean, sustainable, and reliable way to power our lives for centuries to come.

How Does Hydropower Work?

Most of the country's hydropower facilities were built in lakes, streams, and rivers decades ago. They often used large dams that block the water's flow, creating a pool of water above the structure. One or more pipes give that pooled water a path to surge downhill. And as the water rushes through those pipes, it spins a turbine, which runs a generator that sends clean electricity to your home.

Today, most newly constructed hydropower facilities are far smaller and use new techniques to better protect the wildlife and plants that rely on naturally flowing waterways. Fish, for example, must migrate upstream to feed and mate. To help them navigate around our dams, we build fish ladders, so they can climb over the top and swim on. Or we don't block their path at all; some new hydropower facilities divert part of a river or stream into a separate channel. That way, the river and its ecosystem can race on, undisturbed, while we generate power off to the side.

Some hydropower facilities don't just generate power; they store it in the largest "batteries" on Earth. So-called pumped storage hydropower—also known as water batteries—can hold huge amounts of renewable energy for months at a time. This storage is very important. Solar energy and wind power only create electricity when the sun shines and winds blow, but water batteries can store excess energy that can be used at night or during gentle breezes. In the United States, they can store up to 553 gigawatt-hours of energy. That could power the entire country's video gaming for about a week.

What Makes Hydropower So Great?

Hydropower costs less than most other energy sources, making it an affordable source of renewable energy. Except during periods of extreme drought, we can count on water to flow day and night and all year round. And this consistency is critical if we want to rely purely on clean energy sources, such as solar energy and wind power, which can come and go.

New hydropower technologies keep getting better, too. They make it easier to build new facilities without too much disruption to the local environment. And they help cut construction costs, which could make hydropower even more affordable, potentially reducing energy bills across the country.

Want more information on Hydraulic Dam? Feel free to contact us.

Hydropower facilities can also control how much water flows through their turbines and, therefore, how much energy they produce and when. That way, hydropower can fill energy gaps to ensure communities always get the power they need—or restore it. When ice storms, wildfires, or even hackers stop the electric grid from lighting up our lives, hydropower can help. In almost half of all blackouts, it's water that turns the lights back on. Losing power during a heat wave or at a hospital is not just inconvenient; it can be dangerous. Hydropower can save lives.

What Else Can Hydropower Do?

Water housed in hydropower facilities can be used to water crops, put out wildfires, or provide clean drinking water to local communities.

In some areas, such as the drier Western states, the warming climate is likely to cause more droughts, which could threaten water supplies. Because hydropower facilities can absorb and store extra water, they can help communities manage their supplies. In the Northeast, on the other hand, climate change is likely to cause more flooding. Hydropower can help with that, too. Its reservoirs can capture dangerous run-off, preventing those waters from surging into towns and cities where it can threaten properties and lives.

Additional Resources

For more information about hydropower, browse the following resources.

NREL's Hydropower Research – news and updates about NREL's hydropower studies and innovations

An Examination of the Hydropower Licensing and Federal Authorization Process, NREL Technical Report ()

Hydropower Fact Sheet, U.S. Department of Energy's Water Power Technologies Office ()

Hydropower Basics
U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy

How Hydropower Works
U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy

REDi Island: Renewable Energy Discovery Island—a virtual world powered entirely by renewable energy to show applications for hydropower technologies.

Hydropower Stories

In the s, Hydropower Was Gold. What Happened?

Hydropower Means Flexible Power for Our Clean Energy Future

FLASH: Meet the New Superhero of Hydropower

RAPID Changes Are Coming for Hydropower

NREL Announces Winners of the Groundbreaking Hydro Prize

The company is the world’s best hydraulic dam companies supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.