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Published byMarsha Daniels Modified over 6 years ago
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Warm - Up 1. What is the process called when atoms are split?
2. What is the difference in reactions between a nuclear bomb and a nuclear power plant? 3. What are some advantages of nuclear energy? 4. What are some disadvantages of nuclear energy?
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Chapter 18 Renewable Energy
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Renewable Energy Renewable energy – energy from sources that are constantly being formed Solar Wind Water Earth’s heat
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Solar Energy Sun - Medium sized star Nuclear fusion in the core
Fraction reaches the Earth All renewable energy comes directly or indirectly from the Sun
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Passive Solar Heating Sun’s energy directly heats
Passive solar buildings – which way are windows (Northern Hemisphere)? Thick insulation
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Passive Solar Heating Summer – sun in high in the sky
Overhang cools Winter – sun low in the sky Sunlight enters windows
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Active Solar Heating Sun’s energy is captured in collectors
Roof mounted Liquid heated in collectors Heats water for home
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Photovoltaic Cells Solar cells Convert sun’s energy into electricity
Nonpolluting Small electrical current Hundreds of acres of panels to heat a small town
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Solar Cells Extended periods of sunlight Energy stored in batteries
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Wind Power Fastest growing energy source Cost effective
Erected in 3 months
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Wind Farms Windiest spots on Earth – generate more than 10X energy used worldwide Problem – transporting energy in rural areas to urban areas
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Biomass Fuel Plant material, manure, or an other organic material used for energy Burning dung or wood Wood is renewable to an extent
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Methane Bacteria decomposes organic waste – methane
Bio-gas digesters: ferment manure Dung-fired power station: produces electricity Decomposition of trash
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Alcohol and Ethanol Ethanol or alcohol
Fermented fruits or agricultural waste Corn – U.S. Gasohol – blend of gas and ethanol
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Hydroelectricity Energy from moving water Expensive to build
Inexpensive to operate Last longer than fossil fuel plants Disadvantages?
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Micro-hydropower Small streams No big dams Cheaper More remote areas
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Geothermal Energy Energy from heat inside the Earth’s crust
Pumps water or steam into a turbine U.S. in #1
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Geothermal Heat Pump
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Alternative Energy Energy sources that are still in development
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Tidal Power Tide rises – water flows behind dam
Tide lowers – water trapped behind dam Released and turns turbine Expensive
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OTEC Ocean thermal energy conservation
Differences in water temperatures Surface – warm Deep – cold Water boils at low temperatures in low pressure vacuum Boiling water stream turbine
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Hydrogen Gas When burnt combines with oxygen – H2O
Produced when electricity splits water
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Hydrogen Gas Expensive to produce Pollution Must be compressed
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Fuel Cell Fuel cell - produces electricity chemically
Combines hydrogen fuel with oxygen from the air
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Energy Efficiency Energy efficiency (in %) = useful energy out//energy in x 100
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Cogeneration Production of two useful forms of energy from same fuel source Waste heat from industrial furnace to turn turbine
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Green Gadgets Video Clips
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