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Chapter 12Renewable Energy and Conservation
Renewable Energy Sources• Those that are replenished by natural processes
and can be used “indefinitely”.
• Examples include;
• Solar energy
• Wind energy
• Hydropower
• Biomass energy
• Wave Energy and Tidal energy
• Ocean Thermal energy
• Geothermal energy
Alternatives to fossil fuels
• Are currently not utilized to their full potential due to competition with traditional forms of energy ($$$fossil and nuclear $$$)
Hybrid Cars
In Italy
Using alternatives to fossil fuels and nuclear power.
Hybrid Car In Italy
Solar energy• The most attractive renewable energy
source.
• Direct: heats water, buildings, generates electricity.
• Indirect: wind, biomass, and hydropower.
Solar energy
• Heating buildings and water tanks.
• Passive solar heating: uses building designs to heat buildings without fans or pumps.
• South facing windows in the Northern Hemisphere.
• Active solar heating: uses collection devices to gather solar energy (Infrared rays).
Solar energy
• Photovoltaic cells (PV) convert sunlight electricity. (Silicon or gallium arsenide are used to generate a flow of electrons)
flow of electrons = electricity
Solar energy
• Solar Thermal Electric Generation: This system heats a liquid steam spins a turbine electricity.
• Use natural gas Back-ups at night or cloudy conditions.
• Mojave Desert and Whit Cliffs (Australia)
Solar Collector
Wind energy• The most competitive renewable energy
source.• A form of indirect solar energy becomes
mechanical energy (movement of air).• Costs have declined from $.40 to $0.05 per
kilowatt hour.(kWh) (1999)• Wind Farms use wind turbines to to
generate electricity. Found in the U.S. (Great Plains), Denmark, India, and Germany.
• Clean and Ugly (NIMBY).• “bird killing has dropped.”
Hydropower• Water flows back to the sea (hydrologic cycle)
• Concentrated flow (Dams convert Potential energy to kinetic (movement) energy.
• 20% of world’s energy.
• U.S. 1200 plants produce 10% of electricity.
• Change in river flow (reservoirs destroy habitats and property) spawning fish are disrupted (Salmon)
• Arid regions lose a lot of H2O through evaporation.
Wave Energy
• Winds produce waves in the ocean and have the potential to turn turbines and generate electricity.
• Air flow from the waves drives the turbine.
• Osprey plant in Scotland was demolished by a storm one month after it was operational.
Tidal energy
• Bay of Fundy in Nova Scotia has huge differences in high and low tides.
• Dams are constructed to trap high tide water and drain it as the tides recede (turbines produce electricity).
• Not an option for many areas due to the tide levels.
Biomass energy• Oldest human fuel source.
• Indirect form of solar energy uses wood and fast growing plants to produce energy.
• Solids –Such as wood, charcoal, dung, buffalo chips, and peat moss.
• Liquids- Include Methanol (Methyl Alcohol), or Ethanol (Ethyl Alcohol) both inefficient to make.
• Gases-Methane (Swamp gas)
Ocean Thermal energy• Ocean temperature gradients can generate
electricity.
• OTEC or Ocean Thermal Energy Conversion pumps warm surface water into a powerplant Ammonia is boiled(BP –33°C) Ammonia steam drives a turbine electricity is produced. Ammonia is then cooled by the deep cool water and process begins again.
Geothermal energy
• The most widely used of the non-solar renewable energy sources.
• GHP’s or Geothermal Pumps take advantage of the temperature gradients in the earths surface.
• Provide heat in the winter and store heat (heat sink) in the summer.
• Hydrothermal reservoirs use steam to generate electricty.
Energy Conversation is the key!
• Moderating or eliminating wasteful energy activities, and demanding government support for alternative fuels.
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