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Chapter 17

Chapter 17. Alternative Energy Sources. Section 17.1 – Solar Energy. Sun = source of all energy on Earth. Solar energy – energy from the sun It is absorbed by plants and used as fuel by virtually all organisms.

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Chapter 17

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  1. Chapter 17 Alternative Energy Sources

  2. Section 17.1 – Solar Energy Sun = source of all energy on Earth. • Solar energy – energy from the sun • It is absorbed by plants and used asfuelby virtually all organisms. • Fossil fuels contain energy from the remains of organisms so they also contain energy originally from the sun

  3. Section 17.1 – Solar Energy • The sun obtains its energy through thermonuclear fusion. • High temperatures in the sun’s core cause hydrogen nuclei to fuse, or join, forming heliumnuclei. As each helium nucleus forms a loss of mass occurs, this is converted to heat and light energy of the sun.

  4. Section 17.1 – Solar Energy Advantages of Solar Energy • Free • Clean • Non-polluting • Can be collected and stored Drawbacks of Solar Energy • Energy source is not constant • Limited sunlight; like cloudy/rainy days • Devices for storing it are not very efficient (expensive)

  5. Section 17.1 – Solar Energy Passive Solar Energy • Sunlight energy is used directly as a source of light or heat. • The sun’s energy is collected, stored, and distributed naturally in an enclosed dwelling. • Greenhouse • Enclosed car with windows up on a hot day • Not used to produce electricity. • Provides an alternative source of heat. • Helps reduce the use of fossil and nuclear fuels. • Building houses where the windows face the majority of sunlight – dark roof and sides.

  6. Passive Solar Energy

  7. Section 17.1 – Solar Energy Active Solar Energy • Has a greater capacity for storing and distributing energy. • Devices used to collect, store and circulate heat produced from solar energy. • Uses tubes, tanks, fluids, pumps, fans to collect and distribute energy.

  8. Active Solar Energy • Use of solar collectors – mounted on roofs • Use water which heats to steam.

  9. Section 17.1 – Solar Energy

  10. Section 17.1 – Solar Energy Photovoltaic Cells (PV cells) • A solar cell that produces electricity. • Use thin wafers of semiconductor material to produce electricity directly from solar energy. • Sunlight strikes the cell causing electrons to move from one slice of material to the other. • The movement of electrons results in an electric current. • Includes the use of calculators, satellites, and watches.

  11. Section 17.2 – Hydroelectric Energy • Electricity that is produced from the energy of moving water. • Water power is an indirectuse of solar energy. • Construction of damsto control the rate of the water.

  12. Section 17.3 – Wind Energy • Aerogenerators – windmills that are used to generate electricity, also known as wind turbine generators. • Advantages Disadvantages • Free • Unlimited • Nonpolluting • Saves fuel • Wind energy can be used to move ships, pump water, generate electricity. • Not always available • Take up space • Danger to birds • Ugly • Costly

  13. Section 17.4 – Geothermal Energy • The heat generated within the Earth. • It does not involve the energy from the sun. • Source is generated by the decay of radioactive elements deep beneath the ground. • Enough heat is present deep within the Earth to melt rock. • Magma is molten rock. • Lavais magma that has reached the surface. • Includes geysers, steam vents, hot springs

  14. Demo 

  15. Section 17.4 – Geothermal Energy Disadvantages • Not widely available because costly to extract. • Not always easy to locate. • Gives off toxic hydrogen sulfide (corrosive gas).

  16. Section 17.4 – Geothermal Energy • Nuclear fusion – two atomic nuclei fuse to become one larger nucleus. • Source of energy given off from the sun. • Problem - Not yet learned to control and harness the energy and use it efficiently. • The fuel for nuclear fusion is Hydrogen and its isotopes. • H-2 abundant in seawater.

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