Bellringer

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Bellringer Answer the following

1. What is the difference between renewable energy
   and alternative energy?
2. What does the phrase energy conservation mean
   to you?
3. What are the benefits of conservation?
4. What disadvantages to energy conservation can you
   think of?

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Alternative energy and conservationSection 18.2

• Objectives
• Describe three alternative energy technologies.
• Explain the difference between energy efficiency
  and energy conservation.
• Describe two forms of energy efficient
  transportation.

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Alternative energy

• Def Energy sources that are still in development
• Must be shown to be cost effect to become a
  viable option for the future
• What alternative energy sources can you think of?
• Some alternative energy sources
• Tidal power
• Ocean thermal energy conversion
• Hydrogen

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Tidal power

• Tides (high and low) occur twice a day.
• Used 1000 years ago to power mills in France and
  Britain.
• Used today in France, Russia, and Canada to
  generate electricity.
• Disadvantages
• Expensive to build and maintain
• Few suitable locations

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Tidal power
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Ocean thermal energy conversion

• Def using ocean temperature differences to
  produce electricity
• Experimental power station off Hawaii
• Disadvantages
• Expensive and inefficient
• Environmental effects of returning large amounts
  of cold water to the surface?

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Otec video

• http//www.offinf.com/otec_movie.htm

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hydrogen

• Most abundant element in the universe
• Does not contain carbon, so no fossil fuel-type
  pollutants
• When burned, it produces water vapor and small
  amounts of nitrogen oxides.
• Disadvantage takes a lot of energy to produce

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Fuel cell

• Def produces electricity chemically, like a
  battery, by combining hydrogen fuel and oxygen
• The only by-product (or waste) is water.
• Hydrogen can be obtained from alcohol, natural
  gas, or gasoline.

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Other energy sources

• Electricity from bacteria
• Read Science Technology, p.479.
• Water pumps and seesaws in Columbia
• Human-powered washing machines

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Energy efficiency

• Def the percentage of energy put into a system
  that does useful work
• Energy efficiency (in ) energy
  in/energy out x 100
• Overall, more than 40 of all energy used in the
  U.S. is wasted.
• Some solutions are simple better insulation,
  fluorescent light bulbs. Others require sacrifice
  or new technology.

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Energy efficiency (cont.)
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Efficient transportation

• Hybrid cars
• Use a small, efficient gasoline engine most of
  the time
• Also use an electric motor when extra power is
  needed
• Convert some of the energy of braking into
  electricity and store it in the battery
• Gasoline engine shuts off when car is stopped at
  a red light

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Energy conservation

• Def saving energy
• Using more efficient devices
• Wasting less energy
• Some cities offer incentives
• How can we conserve energy around the home?
• In daily life?

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Conservation around the home (Fig. 19, p.471)
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Conservation in daily life (Table 2, p.471)

• Wash clothes in cold water