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Renewable Energy. Renewable resources can be replaced quickly as they are used up. Make up about 10 % of our electricity usage. [http://upload.wikimedia.org/wikipedia/commons/5/51/Sources_of_Electricity_in_the_US_2005_New.png]. Renewable Energy. Wind Energy
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Renewable Energy • Renewable resources can be replaced quickly as they are used up. • Make up about 10 % of our electricity usage [http://upload.wikimedia.org/wikipedia/commons/5/51/Sources_of_Electricity_in_the_US_2005_New.png]
Renewable Energy • Wind Energy • Windmills are used to turn generator turbines. • About 20-25% efficient. [http://www.turf.uiuc.edu/recent/recent1998/misc/CALIFORNIA%20WINDMILL%20FARM3.JPG]
[http://www.deed.state.mn.us/lmi/__shared/assets/0401rs19664.gif][http://www.deed.state.mn.us/lmi/__shared/assets/0401rs19664.gif]
Prices are low after up front costs are taken care of (land, turbines, etc…) Right now, operating wind energy is $0.03-0.04 per kWh
Renewable Energy • Hydroelectric Energy • Allow water from rivers or dams to turn a turbine. • Also tidal energy on the coasts. [http://upload.wikimedia.org/wikipedia/en/8/81/Hydroelectric_dam.png]
Renewable Energy • About $0.04/kWh • Usually high efficiency (30-35%) • In large applications, flooding occurs behind the dam. • Other biological or environmental impacts.
Renewable Energy • Solar Energy • Photovoltaic cells convert sunlight into electrical current. • One type of system acts as a battery, so no generator is involved. [http://www.epa.gov/greeningepa/images/facilities/rtp_roof.jpg]
About 10-25% efficient depending on type Currently around $0.18 per kWh [http://www.eere.energy.gov/tribalenergy/guide/images/chart2_solar_pv.gif]
Renewable Energy • Another system “focuses” sunlight to heat water and create steam. (Generator is used here!) [http://www1.eere.energy.gov/solar/images/photo_troughs_nevada_one.jpg]
Renewable Energy • Geothermal Energy • Using heat from the earth to turn the turbines of a generator. • About 16-20% efficient. • About $0.05 per kWh [http://www.informaction.org/images/energy_drysteam1.gif]