U.S. Department of Energy - Energy Efficiency and Renewable Energy
Energy 101: Hydroelectric Power (Text Version)
Below is the text version for the Energy 101: Hydroelectric Power video:
The video opens with the words "Energy 101: Hydroelectric Power." This is followed by a montage of rivers and streams, then a shot of an older water wheel.
People have been capturing the energy in moving water forthousands of years. And today, it's still a powerful resource that can generate clean, renewable, and affordable electricity.
Shots of dam exteriors and flowing water.
You see, we harness energy from flowing water and convert it to electricity.
The words "Hydroelectric Power" appear on screen, followed by shots of dams.
That's what we call hydroelectric power or hydropower. Waterflows from a higher elevation to a lower elevation, and a hydropower facility uses turbines and generators to convert this motion into electricity.
Exteriors of dams.
America has been using hydropower to generate electricity for more than 100 years now.
The words "7% Electricity From Hydropower" appear onscreen, followed by shots of dam interiors.
And today, about 7% of all our electricity is generated from hydropower, making it the largest source of renewable power.
Shots of dam exteriors, flowing water,and dam turbines and generators.
So what makes hydropower renewable? It's simple: water. Water evaporates into clouds and recycles back to Earth as precipitation.
The words "The Water Cycle" appear on screen with images of clouds and flowing water.
The water cycle is constantly recharging and can be used to produce electricity along the way.
Montage of various dam exteriors and their reservoirs. Interior of dam showing turbines and generators.
How does it work? Basically, there are several ways hydropower technologies can generate electricity. You may recognize dams like this one.
The word "Impoundment" appears onscreen with an image of a dam, moving from the exterior to the interior.
This technology is called an impoundment. The impoundment stores water in a reservoir. When the water is released, it flows through and spins a turbine, turning a generator that produces electricity.
The word "Diversion" appears on screen along with a shot of a diversion channel. Shot of pipelines leading to a turbine, followed by the interiors of the turbine and generator.
Here's another technology. This is a diversion. It channels a portion of a river through a canal or pipe into a turbine and generator system. What's cool about this method is that it uses the natural flow of the river and usually doesn't require a large dam.
The words "Pumped Storage Hydropower"appear on screen with a shot of a reservoir. Graphic of reservoir and animated water flow.
And have a look at this: this is called pumped storage hydropower. Basically it works like a huge battery. To charge the battery,water is pumped back up into a reservoir during periods of low energy use, often during the night when people are using fewer appliances. Then, when people need more power during the day, the water can be released to produce electricity.
Montage of exteriors of dams, followed by shots of dam interiors showing newer turbines and generators.
With how long we've been capturing energy from water, you may think there's nothing new in hydropower technology. Think again — the Departmentof Energy is helping to upgrade many older facilities by increasing the efficiency of the turbines and generators. Operators of neighboring hydropower facilities are also working together to optimize energy production across whole river systems, instead of each dam working alone.
Montage of shots of dam exteriors. The words "80,000 U.S. Dams" appear onscreen, followed by the words "Less Than 3% Are Powered."
And we can add generators — or retrofit — dams that were built without power, like dams used to water crops or prevent floods. Today, there are about 80,000 dams in the U.S., but less than 3% of these dams produce power. That means there's a big opportunity to generate more clean, renewable power at dams we've already built.
Shot of dam interiors, including a computer screen monitoring fish in the dam.
New technology is also making hydropower even more environmentally friendly. For example, researchers are reducing adverse impacts on fish and their natural habitats.
Shot of a fish ladder.
And fish ladders like these let them swim around dams.
Shots of dam exteriors and interiors and a city skyline.
Hydropower is an essential, reliable, and renewable source of clean energy with a rich history. And it's meeting substantial energy demands today. With new technologies, it will be even more efficient and have greater production capacity, powering U.S. homes and businesses for centuries to come.