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IPC—Chapter 10

IPC—Chapter 10. Energy Sources. Fossil Fuels. How many different ways have you used energy today ? Law of Conservation of Energy states : Energy cannot be created or destroyed—only converted or transformed More energy is used in the US than in any other country in the world

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IPC—Chapter 10

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  1. IPC—Chapter 10 Energy Sources

  2. Fossil Fuels • How many different ways have you used energy today? • Law of Conservation of Energy states: Energy cannot be created or destroyed—only converted or transformed • More energy is used in the US than in any other country in the world • (Energy Usage charts—pg. 291)

  3. Fossil Fuels –cont’d. • Fossil fuels— such as petroleum (oil), natural gas and coal: they are formed from the decaying remains of ancient plants and animals • Burning fossil fuels is a more concentrated form of fuel than other sources (ex: wood)

  4. Petroleum • Petroleum—a highly flammable liquid formed by decayed ancient organisms • A mixture of thousands of chemical compounds • Fractional Distillation: A process that separates hydrocarbons in petroleum to be used to produce different materials • Petroleum is used to manufacture fuels, plastics, synthetic fabrics, lubricants, asphalt, etc.

  5. Natural Gas • NaturalGas—gaseous compounds produced by same processes that produce petroleum • Composed mostly of methane • Also contains other hydrocarbon gases • About ¼ of energy consumed in the US comes from burning natural gas • Natural gas powers stoves, furnaces, hot-water heaters, clothes dryers, etc.

  6. Coal • Coal—a solid fossil fuel that is found in mines underground • At one time powered most of the US • Now, 2/3 of energy in US comes from petroleum and natural gas, and about ¼ comes from coal • 90% of coal used in the US is burned by power plants to generate electricity

  7. Origin of Coal • Coal mines were once the site of ancient swamps where large, fernlike plants grew. • Coal formed from this plant material. • Worldwide, the amount of coal that is potentially available is estimated to be 20 to 40 times greater than the supply of petroleum

  8. Generating Electricity • Almost 70% of electrical energy used in the US is produced by burning fossil fuels • The overall efficiency of burning fossil fuels is listed in table 1 on pg. 296 • There are undesirable side effects of burning fossil fuels, such as: smoke, carbon dioxide concentration in the atmosphere, pollutants, sulfur dioxide, etc.

  9. Nonrenewable Resources • Nonrenewable resources—all fossil fuels—resources that cannot be replaced by natural processes as quickly as they are used • Conservation: one way to reduce the use of fossil fuels is to obtain energy from other sources ex:????

  10. Section 2—Nuclear Energy • Some power plants convert nuclear energy to electrical energy (w/out using fossil fuels) • Nuclear power plants produce about 8% of all the energy consumed in the US • There are currently more than 100 nuclear power plants in the US

  11. Nuclear Reactors • Nuclear reactor—uses the energy from controlled nuclear reactions to generate electricity • Reactorcore—where fission takes place in a nuclear reactor • Ex: for every 1 kg of uranium that undergoes fission in the core, 1 g of matter is converted into energy • The energy released = energy released by burning more than 3 million kg of coal

  12. Nuclear Power Plants • Nuclear fission reactors produce electricity in much the same way conventional power plants do • Overall efficiency of nuclear power plants is about 35 %, similar to that of fossil fuel power plants

  13. Risks of Nuclear Power • Nuclear power plants do not produce air pollutants released by fossil fuel burning OR carbon dioxide • HOWEVER: • Mining of uranium can cause environmental damage • Water used as a coolant in the reactor core must cool before released into streams/rivers

  14. Release of Radioactivity • Fuel rods containing radioactive elements could cause damage to living organisms if released from the reactor core • 1986—Chernobyl, Ukraine • Reactor core overheated, chemical explosion blew a hole in the reactor • 28 people died/possible 260,000 exposed to radiation

  15. Nuclear Waste • Nuclearwaste—any radioactive by-product that results when radioactive materials are used • Low-level waste: usually contain a small amt of radioactive material • Usually do not contain radioactive materials w/long half-lives. • Sometimes is released into air or water

  16. More on Nuclear waste • High-level waste: **Generated in nuclear power plants and by nuclear weapons programs **Stored in a deep pool of water **Spent fuel is buried 100’s of meters below ground in stable rock formations or salt deposits

  17. Nuclear Fusion • Fusion—the most concentrated energy source known • Fusion reactions occur only at temperatures of millions of degrees Celsius. • The use of fusion as an energy source remains in the future

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