U N I T 2 ENERGY SOURCES This Unit deals with the different ways energy is produced, the difference between traditional and clean power plants, the advantages and disadvantages of the various forms of energy production and the environmental problems they could cause. A. HYDROELECTRIC POWER PLANTS Flowing water creates energy that can be captured and turned into electricity: this is called hydroelectric power or hydropower. The most common type of hydropower plant uses a dam on a river to store water in a reservoir. Water released from the reservoir flows through a large turbine which rotates and activates a generator to produce electricity. After passing through the turbine, the water re-enters the river on the downstream side of the dam. Hydropower is the leading renewable energy resource. It is reliable, efficient, economical and does not pollute the air. The flow of water through the turbines can also be controlled in order to produce electricity on demand. 20