People have been capturing the energy in moving water for thousands of years.
And today, it’s still a powerful resource that can generate clean, renewable, and affordable
electricity.
You see, we harness energy from flowing water and convert it to electricity.
That’s what we call hydroelectric power or hydropower.
Water flows from a higher elevation to a lower elevation, and a hydropower facility uses
turbines and generators to convert this motion into electricity.
America has been using hydropower to generate electricity for more than 100 years now.
And today, about 7% of all our electricity is generated from hydropower, making it the
largest source of renewable power.
So what makes hydropower renewable?
It’s simple: water.
Water evaporates into clouds and recycles back to Earth as precipitation.
The water cycle is constantly recharging and can be used to produce electricity along the
way.
How does it work?
Basically, there are several ways hydropower technologies can generate electricity.
You may recognize dams like this one.
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.
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.
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.
With how long we’ve been capturing energy from water, you may think there’s nothing
new in hydropower technology.
Think again — the Department of 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.
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.
New technology is also making hydropower even more environmentally friendly.
For example, researchers are reducing adverse impacts on fish and their natural habitats.
And fish ladders like these let them swim around dams.
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.