26.2 Alternative Energy Resources Pages 690 - 697.
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Transcript of 26.2 Alternative Energy Resources Pages 690 - 697.
26.2 Alternative Energy Resources
Pages 690 - 697
Objective 1.0Describe alternative energy
resources
• 1.Solar energy– Advantages
• Freely available• No pollution
– Disadvantages• Nighttime• Cloudy days• Difficult to store solar energy
• Passive solar heating– Building materials store and release heat
• Concrete• Adobe• Brick• Stone• Tile
• Active solar heating– Solar panels
• absorb energy• Heat water• Stores energy as heat in rock or water
tanks
• Solar cookers– Reflective materials concentrate sunlight to
heat pans
• Photovoltaic cells– Convert sunlight energy to electrical energy
• 2. Energy from Water
– Advantages
• Little pollution
• Recreation
• Drinking water
• Irrigation
– Disadvantages
• Sediment accumulation above dam
• Stream bed erosion below dam
• Water quality degrades
• Environmental effects
• Hydroelectric dams– Water moves past turbines– Turbines turn a generator– Generator produces electricity– 20% of world’s electricity– U.S. 10% of electricity– Canada 70% of electricity
Image is PD-gov, by TVA
• Barrier / tidal dams– Use of ocean waves
• Wave action moves a lever arm• Lever arm turns turbines of generator
– Use of tides• Trapped tidal water is released over
turbines
• 3. Geothermal energy
– Advantages
• Abundant and reliable at geothermal sites
– Disadvantages
• Storage of cooled water
• Air and water pollution
• Disrupts ecosystems
• Hard to transport geothermal energy
• Geothermal steam plant– Steam from vents turn turbines
• 4. Wind energy– Advantages
• Readily available at favorable sites• Cheap• Easy to build• Pollution free
– Disadvantages• Steady winds needed
• Wind Farms– Flat, windy areas– Use of wind turbines to generate
electricity
• 5. Nuclear energy– Advantages
• No air pollution
– Disadvantages• Expensive, time consuming to build• Time limits on nuclear plant operation• Radioactive materials • Waste product storage
• Nuclear power plants– Nuclear fission reaction releases heat– Water turns to steam– Steam turns turbines to generate electricity– Water recycled
Boiling Water Reactor
A Typical Power Plant
• 6. Biomass – Advantage
• Renewable– Disadvantages
• Air pollution
• Biogas– Gas + methane mixture– Bacteria in a “digester” container create
methane– Methane piped into home for burning
• Ethanol and Methanol– Grain alcohols from crops– Used in gasoline “gasohol”– Extend gas supplies
• 7. Oil shale and Tar Sand– Advantages
• Supplies petroleum-like substance
– Disadvantages• Processing is expensive• Air and water pollution
• Oil Shale– Kerogen substance found in oil shale– Kerogen vaporized then condensed– Result is “shale oil”
Image: PD-gov
• Tar Sand– “Bitumen” found in tar sand– Bitumen is high- sulfur content oil– Can be refined into a type of crude oil
Image: PD-gov