How Is Hydropower Gathered or Created?

A high-angle view of a hydroelectric plant in Canada.
••• Photos.com/Photos.com/Getty Images

Hydropower is energy that derives from the movement of water. This movement is part of the Earth’s water cycle, which is the continuous circulation of water through the ground, oceans and atmosphere. The amount of energy that moving water provides depends on the volume in motion, and its speed. Water is one of the oldest sources of energy. Ancient civilizations used hydropower for irrigation, and as a grinding mechanism for grain. In the modern period, hydropower provides 20 percent of the world’s renewable energy.

Water Wheel

Water wheel at a rustic lumber mill in Sherbrooke, Nova Scotia, Canada.
••• Hemera Technologies/AbleStock.com/Getty Images

Water wheels were the most common form of hydropower, from over 4,000 years ago through the 19th century. They converted the energy of flowing water into a rotary motion. This motion then powered the movement of stones and levers to grind grain, mineral ore and cut lumber. The wheel lay horizontally or vertically in flowing water, such as a river or stream. Water flow forced the wheel to move when it hit paddles attached to the wheel’s external frame. Water power increased as it flowed through narrow channels or nozzles.

Turbines

A vintage image of the turbine hall at the Boulder Dam, Colorado.
••• Thinkstock Images/Comstock/Getty Images

Water turbines are a development from the water wheel, and precursors of modern electricity generation. Rather than hitting a fixed paddle on a wheel, the water flow activates a spinning rotor that can have hundreds of blades. A shaft attached the rotor links to a turbogenerator, which is a giant magnet with a coiled wire inside of it. An electric current is generated in the turbine as the shaft turns.

Dams

Scenery along the Yangtze River in China before construction of the Three Gorges Dam.
••• China Photos/Getty Images News/Getty Images

Dams impound large volumes of water that flow from rivers, and create a reservoir behind a retaining wall. A penstock is the pipe, or sluice gate, from the bottom of the reservoir, passing through the dam, to a water turbine. Water from the reservoir flows at high pressure from the reservoir to the turbine and generates electricity. The Three Gorges Dam on the Yangtze river in China is the world’s largest hydroelectric installation where water flow powers 32 turbines.

Pumped Storage

Hydropower plant operators can store energy during periods of low customer electricity demand, and release it during periods of peak demand, using pump storage methods. During periods of low demand, water that has already flowed through turbines is pumped back to a separate storage reservoir above the turbines. This water flows back through the turbines during periods of peak demand. The system provides a quick start-up for extra power generation.

Related Articles

Sources of Kinetic Energy
Different Ways to Make Electricity
What Are Water Mills Used For?
How to Calculate Water Wheel Power
What Are the Major Energy Sources on the Earth?
How Is Wave Energy Used to Generate Electricity?
Types of Windmills
How to Build a Micro-Hydro Turbine Generator
Sources of Kinetic Energy
What Is a Gorge in Geography?
Two New Forms of Energy in the Late 1800s
Sources of Energy From the 1800s
How to Charge a 12V Battery With a DC Motor
Facts About the Colorado River
Parts of a Geothermal Power Plant
Advantages & Disadvantages of Constructing Dams
How Are Windmills Used Today?
How to Wire a Car Alternator to a Micro Hydro System
Types of Drainage Basins