1. Lesson 18.2- Hydropower and Ocean Power

2. What Is Hydropower? 1. The movement of water is used to generate electricity. 2. Accounts for about 19% of the world’s electricity. 3. Hydropower is generated by turbines that are turned by moving water. 4. Two Types: a) Water flows through a dam which pushes turbines. b) Naturally flowing water is diverted through turbines.

3. 5.Dams provide constant electricity but can disturb natural habitats. 6.Natural flowing water can lead to a variable supply of electricity.

4. BENEFITS 1.Inexpensive to operate 2.No air pollution 3.Produces relatively cheap electricity 4.Dams provide flood control and water for drinking, agriculture, industry, and recreation. COSTS 1.Expensive to build 2.Changes a rivers flow- creates floods for habitat areas above the dam and reduces water flow to areas downstream (affects fish population) 3.Farmland below a dam is less productive. 4.People are displaced by the building of a dam.

5. Tidal Energy 1.Electricity generated by the flow of ocean water as tides go in and out 2.Tidal waters push turbines in a dam. 3.The best places to harness tidal energy have big differences in the heights of high and low tides. 4.Generates little to no pollution, but shore ecosystems can be negatively affected and very few locations are currently suitable High and low tide in the Bay of Fundy, Nova Scotia

6. Thermal Energy from the Ocean 1.The ocean absorbs solar energy and stores it as heat. 2.Ocean thermal energy conversion (OTEC) converts heat energy in the ocean to electricity. 3.Warm ocean water is used to boil liquids with very low boiling points, generating vapors that can spin turbines. 4.OTEC technology is currently under development; no power plants use this method today. Did You Know? The heat content absorbed every day by tropical oceans is equivalent to the heat content of 250 million barrels of oil.