Hydroelectric power harnesses the energy of flowing water to generate electricity. Water is stored in a reservoir behind a dam and then released through turbines that spin generators to produce electricity. A hydroelectric power plant in Scotland takes advantage of the area's high rainfall to fill its reservoir and uses the 364m elevation difference to power its turbines. Hydroelectric power has advantages of being renewable, producing limited pollution, and reducing flood risks, but dams are expensive to build and can flood habitats.

1. Hydroelectric Power

4. Diagram of an HEP Dam