Hydropower is one of the oldest types of power sources. It also costs less, and is used in every state.
How hydroelectric power works
The water is held behind a dam, making an artificial lake. The force of the water being released makes the blades of a giant turbine spin.
Locations that use Hydropower
Oregon, Washington, and Idaho all use hydropower
Advantages of Hydroelectric energy
It won't pollute or damage the air. It depends on the rain cycle so it is very abundant. It can be controlled on demand for more or less power.