Chapter 13: Energy

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Chapter 13 Energy
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Renewable Energy

• Types
• Solar energy directly from the sun or indirectly
  from
• Wind
• Moving water
• Biomass
• Geothermal Energy

• Renewable energy provides, only 8 of the worlds
  energy
• If subsidies and tax breaks were removed from
  non-renewable energy today, then by, 2050, 50 of
  the earths energy could come form renewable
  sources.

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Using Solar Energy to Heat Water and Houses

• Active solar heating system
• Uses heat absorbing liquids pumped to solar
  collectors outside, then pumped back though the
  house.

• Passive solar heating system
• Heat is allowed in through large superwindows
  facing the direction of the sun, then stored in
  the structures masonry.

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Cooling Buildings Naturally

• Living roofs
• Lightly colored roofs that can reflect up to 80
  of light
• High-efficiency windows

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Solar Thermal Systems

• These systems concentrate and transform energy
  from the sun into high temperature thermal
  energy
• Examples
• Central Receiver System computer controlled
  heliostats concentrate sunlight on a heat
  collecting tower to produce steam to drive a
  turbine.
• Solar cooker used to concentrate heat to cook
  food and purify water.

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Solar Cells
-Photovoltaic (PV) cells made of thin slates of
silicon with traces of metals, emit electrons
when sunlight passes through them.

• Advantages
• Safe/quiet
• Little maintenance
• No pollution when operating
• Works on cloudy days

• Disadvantages
• Currently expensive
• Contains toxic material.
• Fossil fuels used in production
• High land use

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Hydropower

• Uses kinetic energy of flowing and falling water
  to produce electricity.
• Most common method is the use of large dams to
  create reservoirs, whose water is then slowly
  released though the dam turning a turbine and
  creating energy.

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Wind

• Turbines located on land or at sea convert wind
  into electricity
• It has been estimated that only 1/5 of the wind
  energy from the worlds best sites could create 7
  times more electricity than the world currently
  consumes.

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Wind

• Advantages
• Mostly pollution free
• Low cost compared to other energy producers.
• Little land use

• Disadvantages
• Needs steady winds
• Noise pollution
• Unsightly
• Disrupts bird migration if not placed correctly
• Some pollution in construction

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Biomass

• Plant material and animal waste that can be
  burned directly as solid biofuel or converted
  into liquid Biofuels
• 95 of energy use in the poorest countries
• Destroys biodiversity when forests are destroyed
  for biofuels and biomass plantations can deplete
  nutrient- rich soil with overuse.
• The burning of biofuels releases CO2 and
  destroying forests reduces vegetation that could
  capture CO2.

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Liquid Biofuels Created From Plants

• Unlike gasoline and diesel fuel, Biofuels are not
  concentrated in a few countries, eliminating
  reliance on foreign fuel sources.
• Biofuels can be used in pre-existing vehicles
  with only small alterations.
• Examples Biodiesel, Ethanol

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Biodiesel
Biodiesel is produced from the oil and fats of
vegetables.

• Advantages
• Reduced CO2 emissions
• Better gas mileage
• High net energy yield for oil palm crops

• Disadvantages
• Increase NOx emissions and smog
• Higher cost than diesel
• Low net energy yield for soybean crops
• Loss of biodiversity

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Ethanol
Created by converting starch in plants into
sugars which are then processed into Ethanol

• Disadvantages
• Low net energy yield (corn)
• Higher CO2 emissions (corn)
• Higher cost
• May increase food prices

• Advantages
• High octane
• Reduce in CO2 (sugarcane)
• High net energy yield (sugarcane)
• Can be mixed with gasoline or ethanol

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Geothermal Energy
Heat stored in soil, underground rocks and
liquids in the earths mantle

• Geothermal Heat Pump
• During the winter a closed loop of buried pipes
  filled with fluids circulates heat from the
  ground into a building. The system does the
  opposite during the summer storing heat below
  ground.

• Tapping into Hydrothermal Reservoir
• Hot water underground is pumped to the surface
  where it is used to heat houses or to spin
  turbines

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Geothermal Energy

• Advantages
• Very high efficiency
• Lower CO2 emissions than fossil fuels
• Low cost at favorable sights
• Low land use and disturbances

• Disadvantages
• Scarcity of suitable sights
• Can be depleted if used too rapidly
• CO2 emissions
• Noise and ordor

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Hydrogen

• Currently hydrogen fuel cells combine oxygen with
  hydrogen to produce electricity and water vapor.
• Produces more energy per gram than does any other
  fuel and does not produce CO2

• Hydrogen effects on the environment depends on
  the chemical system used to split it from water.
• Current fuel cells are too expensive for
  commercial use

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How Can We Make a Transition to a More
Sustainable Energy Future?

• Step 1 Switch from large centralized macropower
  systems to smaller decentralized micropower
  system.
• Step 2 The temporary use of natural gas to
  transition to locally available energy resources.
• Step 3 Continue to use fossil fuels in large
  quantities but do so more efficiently.

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How the Government Can Help

• Step 1 Keep prices on renewable resources
  artificially low.
• Step 2 Keep prices of non-renewable resources
  artificially high.
• Step 3 Emphasize consumer education

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Nuclear Energy

• Task Boil water to produce steam that spins a
  turbine and generate electricity.
• Uses nuclear fission reaction to provide heat
• Takes place in reactor
• Highly inefficient
• Fuel for reactor is made from uranium ore mined
  from earths crust.

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Nuclear Fuel Cycle

• Three steps
• Mining of uranium
• Using uranium in reactor
• Safely storing the resulting highly radioactive
  waste for thousands of years until radioactivity
  falls to safe levels.

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Advantages of Nuclear Fuel Cycle

• Large fuel supply
• Low environmental impactwithout accidents.
• Emits 1/6 as much CO2 as coal
• Not a lot of land accidents or water pollution.
• Low risk of accidents with safety systems.

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Disadvantages of Nuclear Fuel Cycle

• Cant compete economically without huge
  government subsidies.
• Low net energy yield
• Risk of catastrophic accidents
• No acceptable solution for long-term storage of
  radioactive waste
• Subject to terrorist attacks/spreads knowledge
  for building nuclear weapons.

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Dealing with Radioactive Waste

• 10 years after being removed from a reactor, a
  spent-fuel assembly would still emit enough
  radiation to kill a person standing 1 meter away
  in less than 3 mins.
• Consensus that burial is the safest and cheapest
  method.
• Shoot wastes into space or the sun?
• Bottom Line No agreement whatsoever

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Nuclear Fusion

• Two isotopes of light elements are forced
  together at high temperatures until fused
  together releasing energy in the process.
• Advantages
• No risk of meltdown, or large release of
  radioactive materials from terrorist attack, and
  supplies electricity.
• Still in laboratory stage.

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Energy Efficiency

• Important energy resource
• US could save as much as 43 of all energy it
  uses by improving the energy efficiency of
  industrial operations, motor vehicles, and
  buildings.
• Roughly 84 of all commercial energy is US is
  wasted.

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Solutions to Reducing Energy Waste

• Prolongs fossil fuel supplies
• Reduces oil importsimproves energy security
• Very high net energy yield
• Low cost
• Reduces pollution
• Creates local jobs

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We can Save Energy and Money in Industry

• Cogeneration two useful forms of energy (such as
  steam and electricity) are produced from the same
  fuel source.
• Replacing energy-wasting electric motors would
  help (it consumes ¼ of the electricity produced
  in the US)
• Switch from low-efficiency incandescent lighting
  to high-efficiency fluorescent lighting.

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We can Save Energy and Money in Transportation

• Accounts for 2/3 of US oil consumption
• Low fuel efficiency standards
• Government can give consumers tax breaks or other
  economic incentives for more fuel-efficient
  vehicles.

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We Can Design Buildings that Save Energy and Money

• Better architecture and energy savings in
  buildings could save 30-40 of the energy used
  globally.
• Green building certification standards in 21
  countries.

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We can Save Energy and Money in Existing Buildings

• Insulate the building and plug leaks
• Use energy efficient windows
• Heat houses more efficiently
• Heat water more efficiently
• User energy-efficient appliances
• Use energy-efficient lighting.

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Sources of Energy

• Fossil fuels supply most of our commercial energy
• Almost all of the energy that heats the earth and
  our buildings comes from the sun at no cost to
  us.
• The three indirect solar energy is wind,
  hydropower and biomass

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Commercial Energy

• Comes from extraction and burning nonrenewable
  resources obtained from the earths crust
• 92 of the worlds energy comes from these sources
  
• 86 from carbon containing fossil fuels
• 6 from nuclear power
• The remaining 8 comes from renewable resources

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Fossil Fuels

• We depend heavily on oil
• Petroleum or crude oil is a black, gooey liquid
  that consists for different combustible
  hydrocarbons
• The petroleum is then sent to a refinery to be
  separated into different components with
  different boiling points and this is called
  refining

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How Long Will Crude Oil Last?

• The amount of barrels crude oil used each day
  would stretch from end to end circling the
  equator twice
• Crude oil reserves will be 80 depleted between
  2050 and 2100

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Three Options

• 1. Look for more oil
• 2. Use and waste less oil
• 3. Find other energy sources

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OPEC

• Organization of Petroleum Exporting Countries
• They control most of the worlds crude oil supply
  at about 78 of it
• Members Algeria, Angola, Ecuador, Iran, Iraq,
  Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the
  United Arab Emirates, and Venezuela.
• Saudi Arabia has most of it at 20
• Canada is second with 16

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United States

• We use much more oil than we produce
• We produce about 9 of the world Crude oil and
  use about 25 of it
• We also only have 2 of the worlds oil reserves
• This results in a massive annual transfer of
  wealth from the United States to oil-producing
  countries

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Tar Sand and Oil Shale

• Tar sand is a mixture of clay, sand, water, and a
  combustible organic material with a high sulfur
  content.
• Oil shale are products from oily rocks
• Both of these are potential supply's of heavy oil

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Clean Oil Campaign

• The U.S. coal industry is rich and politically
  powerful.
• For decades it has fought to preserve its profits
  by opposing measures such as stricter air
  pollution standards for coal burning
• In reality there is no such thing as clean coal

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Convert Coal into Gaseous and Liquid Fuels

• Solid coal can be converted into synthetic
  natural gas process called coal gasification