Earth’s Energy Sources Chapter 22 Pearson, 16 Glenco
Energy uses List all of the energy sources you have used today
Solar Energy Heating with solar energy Passive Solar energy Active Solar energy
Passive
Active
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
Energy Usage in the United States
Energy Usage in the United States
Fossil Fuels Formed by decay of ancient plants and animals When burned they produce carbon dioxide and water Petroleum, Natural Gas, and coal
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
Petroleum and by-products List four things in the class room made from petroleum. http://www.msnbc.msn.com/id/37637353/ns/technology_and_science-science/t/just-pelicans-people-cant-avoid-oil-either/#.T2NP8M3SOJo
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
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
Generating Electricity
Coal generation
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.
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.
Efficiency of Power plants Process Efficiency % Chemical Thermal 60 % Water steam 90% Steam turn turbine 75% Turbine generator 95% Tranmission through power lines Over all efficiency 35% 65% is converted to thermal( unusable energy)
Nonrenewable Resources Cannot be replaced by natural processes as quickly as they are used. All fossil fuels are nonrenewable. http://www.theoildrum.com/story/2006/12/13/44528/872
Carbon dioxide According to the graph by how many parts per million (ppm) did the concentration of CO2 increase from 1958 to 2000?
Nuclear Energy
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.
Core of the Nuclear Reactor
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
Nuclear fission A neutron hits a U-235 nucleaus and splits it apart into two smaller nuclei and energy is released
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
Disposal of Nuclear waste Low-level waste: Have low radioactivity Short half-lives Can be released into the air when diluted.
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.
Renewable Energy Resources A Renewable resource is an energy source that is replaced nearly as quickly as it is used
Solar Use Photovoltaic cell that converts radiant energy from the Sun directly into electrical energy. Also called solar cells
How a photovoltaic cell works Only about 7 to 11% efficient
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.
Hydroelectric power Electricity is produced by the energy of moving water
http://www.energy-green.net/blog/catalog.asp?tags=hydro-power http://www.energy-green.net/blog/catalog.asp?tags=hydro-power
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
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.
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
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
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.
Alternative fuels Biomass fuels; burned in the presence of oxygen: wood sugarcane, fibers, rice hulls, animal manure. Hydrogen gas fuel cells