1. Renewable Energy Ch. 18

2. What is Renewable Energy? Energy from sources that are constantly being formed. Many govt. Plan to increase their use of renewable sources European Union plans to produce 12% of their energy from renewable sources by 2010.

3. List of Renewable Energy Solar Energy Wind Power Biomass Hydroelectricity Geothermal Energy

4. Solar Power Power from the sun – Medium sized star that radiates energy from nuclear fusion reactions in its core – Only small amount of energy produced reaches earth

5. Passive Solar Heating Uses the sun’s energy to heat something directly Passive Solar Buildings – Large windows Face south – Solar energy enters windows and warms house – Nighttime – heat is released slowly – Buildings must be well insulated with thick walls and floors to prevent heat loss – Building oriented according to movement of sun

6. Active Solar Heating Solar Energy can be gathered by collectors and used to heat water Mounted on roof Liquid within collector heated by sun Liquid then pumped through a heat exchanger – Heats water for building

7. Photovoltaic Cells A.K.A – Solar cells Invented over 120 years ago Run on nonpolluting solar energy – Why don’t they meet all our energy needs? Produce very little electrical current Require extended periods of sunlight

8. Wind Power Energy from sun warms earth’s surface unevenly Causes air masses to flow in atomosphere – WIND Wind power converts movement of wind into electrical energy Fastest growing energy source in the world!

9. Wind Farms Large arrays of wind turbines California – Supply 280,000 homes Scientists estimate that the windiest spots on earth could generate 10 times the energy used worldwide!

10. Biomass Plant material, manure, and any other organic matter that is used as an energy source AND is considered renewable List of biomass fuel sources – Methane – Alcohol – algae

11. Methane When bacteria decompose organic wastes, can produce methane – Can be burned to generate heat – CHINA More than 6 million households use biogass digesters to ferment manure and produce gas for heating and cooking – USA Some landfills generate electricity by using methane from decomposing trash

12. Alcohol Liquid fuels can be derived from biomass – Ethanol comes from frementing fruit or agricultural waste Corn – major source of ethanol – Gasohol – mixture of ethanol and gas » Produces less pollutants than fossil fuels » Some US states require the use of gasohol

13. Renewable Energy Ch. 18 cont.

14. Hydroelectricity Energy produced from moving water Accounts for about 20 % of worlds electricity Benefits – Dams are inexpensive to operate – No air pollutants – Last much longer than fossil fueled power plants http://techalive.mtu.ed u/meec/module17/Hyd roelectricity.htm http://techalive.mtu.ed u/meec/module17/Hyd roelectricity.htm

15. Hydroelectricity Disadvantages – Changes a rivers flow – Disrupts ecosystems Salmon fisheries in NW US – Sediments are stuck behind dam Reduces mineral richness of land below dam

16. Geothermal Energy Deposits of water in earths crust are heated by energy within the Earth US is worlds largest producer of geothermal energy – Geyers in CA. Produce electricity for 1.7 million households http://www.geysers.com/ geothermal_energy_1mb _peak.wmv http://www.geysers.com/ geothermal_energy_1mb _peak.wmv

17. Geothermal Energy Geothermal heat pumps – More than 600,000 homes in US are heated and cooled by geothermal heat pumps

18. Alternative Energy Describes energy sources still under development – Tidal Power – Ocean Thermal Energy Conversion – Hydrogen

19. Tidal Power Was used over 1000 years ago to power mills in France and Britian Today – Generates power in France, Russia, Canada

20. Ocean Thermal Energy Conversion In tropics, temperature difference between surface of ocean (warmed by solar energy) and deep ocean waters can be as much as 24 degrees C. Use this temp. difference to generate electricity Warm surface water is used to boil sea water

21. Hydrogen Most abundant element in the universe Found in every molecule of living things Does not contain carbon – No pollutants associated with burning fossil fuels and biomass – Makes water vapor as waste product

22. Hydrogen Challenge – Takes a lot of energy to produce Can use electricity from solar cells or wind power to split water molecules to produce Hydrogen Can be stored in pressurized tanks and transported in pipelines