Earth

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Earths Energy Sources

• Chapter 22 Pearson, 16 Glenco

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Energy uses

• List all of the energy sources you have used today

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Solar Energy

• Heating with solar energy
• Passive Solar energy
• Active Solar energy

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Passive
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Active
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Transforming Energy

• Law of conservation of Energy energy is neither
  created nor destroyed only transformed.
• Some energy transformation is not useful for us.
• Example Power lines transform energy into heat.

Published January 27, 2011 By Amanda Kaufmann
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Energy Usage in the United States
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Energy Usage in the United States
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Fossil Fuels

• Formed by decay of ancient plants and animals
• When burned they produce carbon dioxide and water
• Petroleum,
• Natural Gas, and coal

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Petroleum

• Fossil Fuel made of Hydrocarbons
• Produced by separating the liquid oil in a
  process called Fractional distillation.
• Oil is pumped into the bottom of a tower and
  heated. Materials rise to the top depending on
  boiling point and are collected. Some are pulled
  from the bottom, like asphalt.
• Other uses Plastics, lubricants, asphalt

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Petroleum and by-products

• List four things in the class room made from
  petroleum.

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Natural Gas

• Composed mainly of Methane.
• Natural gas contains more energy per kilogram
  than either petroleum or coal.
• Produces fewer pollutants than other fossil fuels

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Coal

• Solid fossil fuel found underground
• One fourth of our energy comes from coal.
• Coal is formed from organic material deposited in
  ancient swamps.
• Burning coal results in more pollutants

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Generating Electricity
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Coal generation
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Electricity Generation

• Fuel is burned to heat a boiler of water
• Steam is produced and causes the turbine to spin
• Turbine is connected to an electric generator
• Electric current is produced when the spinning
  turbine shaft rotates magnets inside the
  generator.

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Simple Electric Generator

• When the coil is turned, the magnets cause
  movement in the electrons within the coil.
• The movement of
• electrons causes
• an electric current.

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Efficiency of Power plants
Process Efficiency
Chemical? Thermal 60
Water? steam 90
Steam? turn turbine 75
Turbine? generator 95
Tranmission through power lines 90
Over all efficiency 35
65 is converted to thermal( unusable energy)
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Nonrenewable Resources

• Cannot be replaced by natural processes as
  quickly as they are used.
• All fossil fuels are nonrenewable.

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Carbon dioxide

1. According to the graph by how many parts per
   million (ppm) did the concentration of CO2
   increase from 1958 to 2000?

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Nuclear Energy
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Nuclear Power

• Energy is released when the nucleus of an atom
  breaks apart.
• Nuclear power plants produced 8 of all power in
  2003.
• There were 104 nuclear reactors at 65 power
  plants in the US.

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Core of the Nuclear Reactor
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Nuclear power

• Only certain elements
• Uranium 235
• Naturally occurring at 0.7 so it is enriched to
  3-5
• Inside the reactor core fuel pellets are placed
  in a tube the core contains 100,000 Kg of uranium
  in fuel rods
• Energy released by 1 gram 3 million kg of coal

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Nuclear fission

• A neutron hits a U-235 nucleaus and splits it
  apart into two smaller nuclei and energy is
  released

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Risks of Nuclear power

• Mining of Uranium causes enviornmental damage.
• Coolant water must be cooled before discharge
• The most serious is the release of radioactivity

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Disposal of Nuclear waste

• Low-level waste
• Have low radioactivity
• Short half-lives
• Can be released into the air when diluted.

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• High-Level Waste
• The spent fuel rods
• Stored in water
• Will remain radioactive for for tens of thousands
  of years
• Can be sealed in glass and buried in salt mines.

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Renewable Energy Resources

• A Renewable resource is an energy source that is
  replaced nearly as quickly as it is used

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Solar

• Use Photovoltaic cell that converts radiant
  energy from the Sun directly into electrical
  energy. Also called solar cells

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How a photovoltaic cell works

• Only about 7 to
• 11 efficient

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Uses of Solar energy

• More expensive in 2003 than burning fossil fuels
• Another method is to use the sun to heat a fliud
  that then heats steam toturn a turbin to generate
  power.

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Hydroelectric power

• Electricity is produced by the energy of moving
  water

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• http//www.energy-green.net/blog/catalog.asp?tags
  hydro-power

http//www.energy-green.net/blog/catalog.asp?tags
hydro-power
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Advantages of Hydro power

• 8 of all US power is made this way
• Efficient because no heat is involved that can
  take away from the energy used to turn the
  turbines
• Without any pollution
• Dams form lakes that can be used for drinking
  water and irrigation

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Disadvantages

• Have to have a place to build the dam near the
  regions that need to power
• Destroys the area around the dam
• Fish cannot migrate
• Fish ladders are added to dams but still reduce
  the fish.

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Tidal Energy

• Gravity from the sun and moon bulge the earths
  oceans (tides)
• Hydroelectric power can be generated by the
  tides. As the tide comes in and out it turns a
  turbine
• Pollution free
• Only a few places have large enough tides to
  produce electricity

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Wind Energy

• Windmills historically pump water, grind grain.
• For electricity they are 20 efficient( and
  improving)
• Only a few places have enough wind
• Noisy
• Change landscape appearance, disrupt bird
  migrations.
• They do not consume any nonrenewable resource and
  do not pollute

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Geothermal energy

• Energy from the earth.
• 16 efficient
• Can release gases and bring brine to the surface
• Only can be used where magma is close to the
  surface.

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Alternative fuels

• Biomass fuels burned in the presence of oxygen
  wood sugarcane, fibers, rice hulls, animal
  manure.
• Hydrogen gas fuel cells