1. Water has long been used as a source of energy, since Greeks who used water wheels over 2,000 years ago. For over a century, hydropower has been used to generate electricity thanks to falling water and tides of oceans. Hydroelectric Power L’autore è il solo responsabile di questa comunicazione. L’Unione europea declina ogni responsabilità sull’uso che potrà essere fatto delle informazioni in essa contenute. Co-finanziato Dal Programma LLP dell’Unione Europea

2. Hydroelectric power stems from the process of using water’s energy as it flows from higher to lower elevation, rotating hydraulic turbines to create electricity. Tidal power uses the same principle to generate hydroelectricity. The use of water to produce electricity is an alternative to fossil fuels. Use of hydroelectric power

3. Advantages Hydropower is a clean, renewable source of energy Emitting a very low level of greenhouse gases It can be highly automated once installed thanks to a low operating cost The power is generally available on demand since the flow of water can be controlled

4. Disadvantages Dams can block fish passage to spawning grounds or to the ocean even if now many plants have measures to help reduce this impact The diversion of water can impact stream flow, or even cause a river channel to dry out, degrading both aquatic and streamside habitats Hydroelectric plants can have an impact on water quality by lowering the amount of dissolved oxygen in the water Sediments and nutrients can be trapped and the lack of water flow can create a situation for undesirable growth and the spread of algae and aquatic weeds The technology must still overcome obstacles like space requirements, building costs, environmental impacts, and the displacement of people

5. Hydropower is very common in countries where there is an abundance of rivers and lakes, as in Canada and in USA, in Italy almost half of renewable energy is produced by hydroelectric power. CHINA USA BRASIL CANADA JAPAN RUSSIA INDIA NORWA Y FRANCE ITALY CONSUMPTION OF HYDROELECTRICITY IN ITALY REST OF THE WORLD HYDROPOWER CAPACITY INSTALLED IN 2011