Energy%20Efficiency%20and%20Renewable%20Energy

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Energy Efficiency and Renewable Energy

• Chapter 16

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16-1 Why Is Energy Efficiency an Important
Energy Resource?

• Concept 16-1 We could save as much as 43 of all
  the energy we use by improving energy efficiency.
  

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We Waste Huge Amounts of Energy

• Energy conservation
• A decrease in energy use as a result of a
  decrease in the amount of wasted energy Use
  less
• Energy efficiency
• The measure of work we can get out of a unit of
  energy we use Use it better
• Four widely used devices waste large amounts of
  energy
• Incandescent light bulb 95 lost as heat
• Internal combustion engine 94 of the energy
  from fuel wasted
• Nuclear power plant 92 of energy is wasted
  through nuclear fuel and energy needed for waste
  management
• Coal-burning power plant 75-80 of the energy
  released by burning coal is lost

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Flow of Commercial Energy through the U.S.
Economy

• 84 of all commercial energy used in the U.S. is
  wasted.
• 41 wasted due to the 2nd law of thermodynamics.
• Only 9 of the total energy put into the U.S.
  economy results in useful energy.

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Advantages of ReducingUnnecessary Energy Waste
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16-2 How Can We Cut Energy Waste?

• Concept 16-2 We have a variety of technologies
  for sharply increasing the energy efficiency of
  industrial operations, motor vehicles, and
  buildings.

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We Can Save Energy and Money in Industry

• Industry accounts for 38 of U.S. energy
  consumption. It can save energy and money by
• Produce both heat and electricity from one energy
  source (cogeneration or combined heat and power,
  CHP)
• Use more energy-efficient electric motors
• Recycle materials
• Switch from low-efficiency incandescent lighting
  to higher-efficiency compact fluorescent (CFL)
  and LED lighting
• Update the old/wasteful electrical grid system
  (how electricity is transmitted from the power
  plant to the consumer)
• Utility companies promote use of energy
• Instead, should promote conservation

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We Can Save Energy and Money in Transportation

• Transportation accounts for 2/3 of U.S. oil
  demand and is a major source of air pollution.
• We can save energy in transportation by
  increasing fuel efficiency and making vehicles
  from lighter and stronger materials.
• Corporate Average Fuel Economy (CAFE) standards
• The average fuel economy, in miles per gallon
  (mpg), of a manufacturers fleet of passenger
  cars and/or light trucks
• Fuel-efficient cars are on the market
• Tax breaks for buying fuel-efficient cars

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Average Fuel Economy of New Vehicles Sold in the
U.S. and Other Countries

• CAFE standards had not increased since 1985.
• In May 2009, President Obama increased the
  standards 5 per year towards a goal of 35.5 MPG
  by 2016.
• This represents an average of an 8 MPG increase.
• Still well below Europe and Japan.

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More Energy-Efficient Vehicles Are on the Way

• Hybrid vehicles have two types of engines working
  together to achieve higher gas mileage (15-70
  more) and lower engine exhaust emissions
• A standard gas powered engine
• An electric motor assist powered by a
  rechargeable nickel-metal hydride (NiMH) battery
  pack
• Gasoline-electric hybrid car
• Mostly gassome electric
• Plug-in hybrid electric vehicle
• Mostly electricsome gas
• Electric vehicle (EVs)
• ALL electric

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Solutions A Hybrid-Gasoline-Electric Engine Car
and a Plug-in Hybrid Car
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Solutions A Hybrid-Gasoline-Electric Engine Car
and a Plug-in Hybrid Car
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More Energy-Efficient Vehicles Are on the Way

• Hybrid cars accounted for 3 cars on the road in
  2009.
• Up from than 1 in 2007
• Typically cost 3-4,000 more than non-hybrid
  models.
• Plug-in hybrids can get twice the mileage of
  gasoline-electric hybrid cars, but
• How is the electricity generated?
• Electricity from coal or nuclear power plants
  JUST AS BAD
• Electricity produced by wind or solar energy
  GOOD
• Analysts estimate that hybrid cars could make up
  as much as 20 of the car market by the year
  2020.
• The boost in sales will be pushed by consumer
  demands and stricter government regulations on
  CO2 emissions.

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Science Focus The Search for Better Batteries

• Current obstacles to hybrid or electric vehicles
• Storage capacity of battery
• Currently about 100 mile range
• Charging time
• 8 hours for a Nissan Leaf (available NOW)
• 3 hours for a Ford Focus EV (available in 2012)
• Use of rare earth metals for battery construction

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We Can Design Buildings That Save Energy and
Money

• Green architecture
• Makes use of passive solar heating, natural
  lighting, natural ventilation, rain water
  collection, cogeneration of heat/electricity,
  geothermal heat pumps, and recycled building
  materials
• Living or green roofs
• Superinsulation
• U.S. Green Building Councils Leadership in
  Energy and Environmental Design (LEED)

Graded on 100 possible points Certified - 40 -
49 points Silver - 50 - 59 points Gold - 60 - 79
points Platinum - 80 points up
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We Can Save Energy and Money in Existing
Buildings

• Insulate and plug leaks
• Use energy-efficient windows
• Stop other heating and cooling losses
• Heat houses more efficiently
• Heat water more efficiently
• Use energy-efficient appliances
• Use energy-efficient lighting

• About 1/3 of the heated air in typical U.S. homes
  and buildings escapes through closed windows,
  holes, and cracks.

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Individuals Matter Ways in Which You Can Save
Money Where You Live
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Why Are We Still Wasting So Much Energy?

• Low-priced fossil fuels and few government tax
  breaks or other financial incentives for saving
  energy promote energy waste.

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We Can Use Renewable Energy in Place of
Nonrenewable Energy Sources

• A variety of renewable-energy resources are
  available but their use has been hindered by a
  lack of government support (subsides) compared to
  nonrenewable fossil fuels and nuclear power.
• Direct solar
• Moving water
• Wind
• Geothermal

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16-3 What Are the Advantages and Disadvantages of
Solar Energy?

• Concept 16-3 Passive and active solar heating
  systems can heat water and buildings effectively,
  and the costs of using direct sunlight to produce
  high-temperature heat and electricity are coming
  down.

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Solar Power
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We Can Heat Buildings and Water with Solar Energy

• Passive solar heating system
• Absorbs and stores heat from the sun directly
  within a structure without the need for pumps to
  distribute the heat.
• House faces South

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We Can Heat Buildings and Water with Solar Energy

• Active solar heating system
• Pumping a liquid such as water or an oil through
  rooftop collectors
• Can also be used to provide hot water

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Trade-Offs Passive or Active Solar Heating
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We Can Cool Buildings Naturally

• Technologies available
• Superinsulation and high-efficiency windows
• Overhangs or awnings on windows
• Light-colored roof
• Reflective insulating foil in an attic
• Geothermal pumps
• Plastic earth tubes underground

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We Can Use Sunlight to Produce High-Temperature
Heat and Electricity

• Solar thermal systems
• Sunlight is directed towards a central tower
  where and oil absorbs the heat and is used to
  create high temperature steam to turn a turbine.

• Large arrays of solar collectors in sunny deserts
• Costs are high and energy yield is low.

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Solutions Woman in India Uses a Solar Cooker

• Solution to the fuel wood crisis?

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We Can Use Solar Cells to Produce Electricity

• Photovoltaic (PV) cells (solar cells)
• Convert solar energy to electric energy
• Can be made in all shapes and sizes and can be
  included in the building design and construction.

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We Can Use Solar Cells to Produce Electricity

• Their costs are high, but expected to fall with
  mass production, new designs, nanotechnology.
• Solar cells can be used in rural villages with
  ample sunlight who are not connected to an
  electrical grid.
• Mostly for pumping water

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Trade-Offs Solar Cells, Advantages and
Disadvantages

• Solar cells currently only 0.2 of the worlds
  electricity
• Solar power has the largest POTENTIAL for
  supplying electrical power to the world.

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16-4 Advantages and Disadvantages of Producing
Electricity from the Water Cycle

• Concept 16-4 Water flowing over dams, tidal
  flows, and ocean waves can be used to generate
  electricity, but environmental concerns and
  limited availability of suitable sites may limit
  the use of these energy resources.

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Hyrdopower
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We Can Produce Electricity from Falling and
Flowing Water

• Hydropower
• Build a high dam across a large river
• Water builds up into a reservoir
• Let water flow through large pipes and turn
  turbines to produce electricity
• Worlds leading renewable energy source used to
  produce electricity
• 16 of the worlds electricity
• 99 in Norway, only 7 in the U.S.

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We Can Produce Electricity from Falling and
Flowing Water
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Trade-Offs Large-Scale Hydropower, Advantages
and Disadvantages
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Tides and Waves Can Be Used to Produce
Electricity

• Ocean tides and waves and temperature differences
  between surface and bottom waters in tropical
  waters are not expected to provide much of the
  worlds electrical needs.
• Few suitable sites
• High costs
• Equipment corrosion
• Only two large tidal energy dams are currently
  operating one in La Rance, France and Nova
  Scotias Bay of Fundy (where the tidal difference
  can be as high as 63 feet).