Hydropower harnesses the kinetic energy inherent in the power of flowing water.

Though it’s been around thousands of years, and generates nearly 25 percent of the world’s electricity, hydropower doesn’t get much play in the media, at least compared to solar and wind. But this fascinating technology should garner more attention as one of six renewable energies the U.N.’s IPCC predicts will provide 77 percent of the world’s power by 2050.

Hydropower relies on energy from the sun to initiate the water cycle, also known as the hydrologic cycle. It’s a basic, naturally-occurring phenomenon that we all learned about in elementary school:

• Water evaporates from the heat of the sun
• Evaporated water collects in the form of clouds
• Clouds rain down precipitation back into water sources

In other words, the world is continually renewing the water sources on which hydropower depends.

To harness the kinetic energy inherent in the power of flowing water, hydropower plants use a 7-step process, as outlined by Discovery’s HowStuffWorks:

1) A dam holds water back to create a reservoir.

2) Intake gates on the dam open and gravity pulls the water through the penstock, a pipeline that leads to the turbine. Water builds up pressure as it flows through this pipe.

3) The water strikes and turns the large blades of a turbine, which is attached to a generator above it by way of a shaft.

4) As the turbine blades turn, so do a series of magnets inside the generator. Giant magnets rotate past copper coils, producing alternating current (AC) by moving electrons.

5) The transformer inside the powerhouse takes the AC and converts it to higher-voltage current.

6) Out of every power plant come four wires: the three phases of power being produced simultaneously plus a neutral or ground common to all three.

7) Used water is carried through pipelines, called tailraces, and re-enters the river downstream.

In the U.S. alone there are more than 2,000 hydropower plants. In fact, it’s the nation’s largest source of renewable energy. And worldwide, hydropower provides electricity to more than a billion of us.

SOURCE: How Hydropower Plants Work

Meredith Simonds Hydropower hydrologic cycle, hydropower, Renewable Energy, water, water cycle