Earth Science

Natural Resources

Hydroelectric Power

Study Tip
Hydroelectric power, much like wind power or geothermal power, requires some natural force to move turbines that generate electricity.

Hydroelectric Dam

  • In a hydroelectric plant, a dam across a riverbed holds a stream to create a reservoir.
  • The water is allowed to flow into a large turbine.
  • As the water moves, it has kinetic energy, which makes the turbine spin. The turbine is connected to a generator, which makes electricity
Study Tip
Hydroelectric power, much like wind power or geothermal power, requires some natural force to move turbines that generate electricity.
Study Tip
The same way a person may cast a shadow over another person when they stand under the sun, planets or celestial bodies that have aligned themselves cast shadows over one another as well.

Applications

  • Colorado’s Hoover Dam generates about 4 billion kilowatt-hours of hydroelectric power each year.
  • This power is used in Nevada, Arizona, and California—enough to serve 1.3 million people.

Tidal Power Stations

  • Tides come onto the shore, and the water from tide can be trapped in a dam.
  • Energy is produced in a similar fashion to a hydroelectric dam.
Hydroelectric Dam
Advantages
Disadvantages
  • Generates power without pollution
  • Renewable energy is created as long as the stream continues to flow
  • There are a limited number of suitable dam sites
  • Affects the stream’s ecosystem, since the dam disrupts river flow
Concept Check
  • How do hydroelectric dams work?
  • What are the advantages and disadvantages of using hydroelectric power?