Chapter 12 Renewable Energy and Conservation

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Chapter 12Renewable Energy and Conservation
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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

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Alternatives to fossil fuels

• Are currently not utilized to their full
  potential due to competition with traditional
  forms of energy (fossil and nuclear )

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• Hybrid Cars
• In Italy

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• Using alternatives to fossil fuels and nuclear
  power.

Hybrid Car In Italy
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Solar energy

• The most attractive renewable energy source.
• Direct heats water, buildings, generates
  electricity.
• Indirect wind, biomass, and hydropower.

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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).

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Solar energy

• Photovoltaic cells (PV) convert sunlight ?
  electricity. (Silicon or gallium arsenide are
  used to generate a flow of electrons)

flow of electrons electricity
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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)

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Solar Collector
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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.

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Hydropower

• Water flows back to the sea (hydrologic cycle)
• Concentrated flow (Dams convert Potential energy
  to kinetic (movement) energy.
• 20 of worlds 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.

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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.?

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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.

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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)

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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 33C) ? Ammonia steam drives a
  turbine ? electricity is produced. Ammonia is
  then cooled by the deep cool water and process
  begins again.

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Geothermal energy

• The most widely used of the non-solar renewable
  energy sources.
• GHPs 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.

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Energy Conversation is the key!

• Moderating or eliminating wasteful energy
  activities, and demanding government support for
  alternative fuels.