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Energy Efficiency

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... Fuel Cell Cars. Ecocars or ... Compare World Trade Center to Ga. Power Company building in Atlanta- features ... New kinds of solar cells are in the works ... – PowerPoint PPT presentation

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Title: Energy Efficiency


1
Energy Efficiency
  • The Rocky Mountain Institute was planned and
    built by energy experts - passive heating, super
    insulation and partly earth sheltered. It makes
    use of the following
  • super insulation
  • temperature monitors operate shutters, etc.
  • solar cells
  • The renewable energy revolution begins!

2
CHAPTER 20
  • ENERGY EFFICIENCY AND RENEWABLE ENERGY

3
The importance of improving energy efficiency
  • 81 of all commercial energy used in the U.S. is
    wasted we waste as much energy as 2/3 of the
    world consumes
  • Amory Lovings says we should stop driving
    Petropigs and stop living in energy sieves
  • Energy efficiency is percentage of total energy
    input that does useful work in an energy
    conversion system

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The importance of improving energy efficiency -2
  • Energy-efficient systems may be more expensive
    initially, but have lower life-cycle cost
    initial cost lifetime operating costs (includes
    extraction, transporting, processing, etc.of
    fuels)
  • Compare cost of electricity to solar energy
  • Dont use high quality energy when lower quality
    of energy can do the job.

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The importance of improving energy efficiency -3
  • Three least efficient energy-using devices are
  • incandescent light bulbs - 95 waste
  • internal combustion vehicles - 90 waste
  • nuclear power plants - waste of fuel waste of
    energy to dispose of dangerous wastes

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Ways to improve energy efficiency
  • Use of waste heat which cannot be recycled so
    rate of flow to environment is slowed
  • In Industry use
  • Co-generation - combined heat and power systems -
    waste heat used for another purpose
  • Replace energy-wasting electric motors with
    motors with adjustable speed drives

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Ways to improve energy efficiency
  • In Industry- Other energy-saving measures
  • High efficiency lighting
  • Recycle, reuse and repair
  • Change regulation of electric utility companies

12
Saving Energy in Transportation
  • Increase fuel efficiency in vehicles
  • opposition by automakers since 1985
  • small, fuel-efficient prototypes made, but not
    mass-produced - higher cost
  • inflation adjustments --gt low gasoline prices
  • what about Lovins freebates
  • Move more people and freight by trains and boats
    or better designed trucks

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Electric Cars
  • No pollution from the cars
  • Electricity to recharge batteries --gt pollution
    elsewhere unless solar or wind is source of
    power
  • limited range and expensive batteries

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Hybrid and Fuel Cell Cars
  • Ecocars or Supercars use
  • small hybrid electric-internal combustion engine
    using fuel and
  • small battery (recharged by engine) for
    acceleration
  • Fuel cell cars - two electrodes in electrolyte
  • hydrogen oxygen reaction --gt 50-60 efficient

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Saving Energy in Buildings
  • Compare World Trade Center to Ga. Power Company
    building in Atlanta- features
  • largest surface faces south
  • each floor blocks hot sun from lower floors
  • lighted desks, not lighted rooms
  • In general - reduce energy and CO2 emissions, and
    save money
  • Better insulation - even bales of straw

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Energy Efficient Building
  • Besides super insulation
  • Passive solar heating
  • High efficiency natural gas furnace
  • Heat pumps in warm climates
  • Least efficient is coal or nuclear fired
    electricity
  • Plug up leaks and energy-saving windows
  • even covering water heater and ducts

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Energy Efficient Building-3
  • Set higher energy-efficient standards for new
    buildings
  • Buy energy efficient lights and appliances
  • Energy waste results from
  • underpriced fossil fuels
  • government subsidies and tax breaks
  • not using life cycle cost analysis

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Direct use of solar energy for heat and
electricity
  • If current subsidies for fossil fuels and nuclear
    energy are phased out, renewable energy sources
    will account for 50 of energy production - from
  • improvements in energy efficiency
  • mix of renewable energy from several sources

26
Direct use of solar energy for heat and
electricity -2
  • Benefits of this change
  • save money
  • create jobs
  • decrease oil imports
  • decrease pollution and environmental degradation
  • increase military, economic and environmental
    security

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Solar energy to heat homes and water
  • Passive solar energy captures sunlight directly
    within structure - slow storage and release of
    energy
  • Active solar heating system uses collectors and
    fans/pumps for distribution

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Cooling houses naturally
  • Trees, overhangs, awnings, insulating foil and
    windows
  • Earth tubes - soil temperature is cooler

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Solar energy for high temperature heat and
electricity
  • Solar thermal systems - power tower is central
    solar receiver heliostats - mirrors that track
    the sun - govt. subsidized project in California
  • Solar thermal plant - distributed receiver
    system- oil in pipes is heated and distributed
  • Parabolic dish collectors

37
Solar energy for high temperature heat and
electricity -2
  • Non-imaging optical solar concentrator -
    intensifies solar energy
  • Solar cookers - for developing countries -
    decrease fuel wood use

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Solar energy to make electricity
  • Photovoltaic (solar) cells - sunlight strikes
    silicon atoms - electrons released--gt electric
    current many cells together
  • Used in roof shingles, in solar-electric window
  • What is green design? Oberlin College
    Environmental Studies Center
  • BP Amoco to use solar panels on service stations

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Solar for the future
  • New kinds of solar cells are in the works
  • Ideal technology for developing countries where
    commitment has not been made to fossil or nuclear
    fuel energy generation
  • Need aggressive programs to encourage utilities
    etc. to utilize solar energy

44
Electricity from moving water
  • Large-scale hydropower projects - reservoir
    water flows to turbines at controlled rates
  • Small-scale hydropower projects - no reservoir
    output varies with stream flow
  • Pumped storage hydropower systems - at surplus
    energy times - energy pumps water to higher
    reservoir for later release

45
Electricity from moving water
  • Problems due to environmental and social
    consequences of large dams
  • wildlife is threatened
  • river flow is disrupted
  • wetlands are destroyed

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Tides and Wave electricity
  • High and low tides - flow into and out of bay --gt
    spin turbines
  • Functions in limited areas - 2 in operation
  • Wave generation of electricity might be possible
    in some coastal areas

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Heat stored in water --gt electricity
  • Ocean thermal energy conversion- based on
    temperature differences - research and
    development stage

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Saline Solar ponds
  • Makes use of differences in density of water at
    different depths facility at Dead Sea had high
    operating costs

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Freshwater solar ponds
  • Black plastic bags filled with water - covered by
    fiberglass insulation panels
  • Requires no energy storage and backup systems no
    pollution, small energy yield

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Electricity from Wind
  • Worlds fastest growing energy resource
  • But only 1 in U.S many good potential areas -
    Saudi Arabia of wind
  • Wind farms
  • Other countries - China is wind superstar
  • Should be one of cheapest energy sources in next
    decade - could be used to make hydrogen gas from
    water --gt fuel cells

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Energy from biomass
  • Burning of wood and manure
  • Can be used to turn turbines --gt electricity
  • Use of fast growing plants (biomass)
  • Bagassse - residue from sugar cane harvest - used
    in Hawaii and Brazil
  • Must be used where produced for
  • Manure better used for fertilizer?
  • Burning trash in incinerators - using heat?

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Biomass to gaseous and liquid fuels?
  • Biogas - methane and CO2
  • liquid ethanol
  • liquid methanol
  • biogas digester - anaerobic bacteria convert
    plant and animal waste to methane for heating and
    cooking
  • gasohal - gasoline mixed with ethanol

65
Solar-Hydrogen Revolution
  • Hydrogen gas combine with oxygen --gt water - no
    pollution
  • Water can be split into hydrogen oxygen
  • But it takes energy to release the hydrogen from
    natural gas or steam
  • A better possibility is solar energy to make
    hydrogen - photovoltaic-photoelectrochemical cell

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