1. Renewable Energy

2. Solar • Solar energy is harnessing energy from the sun’s rays • Passive Solar – Placing buildings strategically to take advantage of the sun’s heat • Example: Log Homes • Active Solar – uses solar panels to convert energy into a usable form such as electricity

3. Benefits of Solar: • Readily available • Renewable • Fairly simple system • Pollution free energy source • Can sell back extra energy to the power company • Drawbacks of Solar: • High start up cost for active solar energy system • Location dependent (Seattle would not be a good city for solar energy)

4. Wind • Wind energy is converted into a usable energy form by using wind turbines www.windenergyplanning.com www.lacoastpost.com

5. Benefits of Wind Power: • Readily available • Can sell back extra power • Pollution free energy source • Drawbacks of Wind Power: • Disrupts migration patterns • Turbine farms are not aesthetically pleasing • Turbines are expensive • Good for specific locations only

6. Hydro • Hydro power is mechanical energy derived from water • Most hydropower is generated by damming rivers • Using waves or ocean currents is being researched as a source of hydropower www.southeastasia.biz

7. Three Gorges Dam in China www.livescience.com

8. Three Gorges Dam • 1.5 miles long • 574 feet deep • $23 billion • 13 cities and 1,300 villages were flooded

9. www.howstuffworks.com

10. Benefits of Hydropower • Readily available • No pollution produced • Constant source of power • Drawbacks of Hydropower • Damming rivers disrupts ecosystems, causes sediment to build up and disruptst he natural flow of a river

11. Geothermal • Geothermal energy uses natural underground heat sources • When heat escapes the earth in the form of steam, the steam is used to turn a steam turbine which converts the heat energy into electrical energy

12. Benefits of Geothermal: • When drilled correctly, little pollution is produced • Takes up a relatively small area, does not disrupt the landscape • Drawbacks of Geothermal: • Can only be used in a limited capacity • Very location specific • May run out of steam • May release hazardous gasses or minerals if drilled improperly

13. Biomass • Biomass is burning biomass fuel in a specialized burner. Steam generated turns a steam turbine which turns mechanical energy into electrical energy

14. Biomass at the Denver Zoo! • Trash and animal waste is converted into pellets • The pellets are put into a gassifier and heated to 400 degrees! • When hot enough, a gas is emitted that is converted by micro gas turbines into electrical energy • Denver Zoo

15. Benefits of Biomass • Less waste in landfills Readily available • Drawbacks of Geothermal • Not currently available on a large scale basis