1. Electrical Energy Sources and Alternatives

2. Coal Energy
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Approximately 60-70% of world energy comes from fossil fuels: oil, coal and natural gas
Fossil fuels were formed when plants and animals decomposed during prehistoric times
Some power plants are fueled by coal
Coal and nuclear power plants heat water into steam that may drive turbines

3. Turbine Generators
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A turbine is a long shaft with blades that is propelled by steam or water
Each turbine rotates wire coils in a generator to produce electricity
Hydroelectric dams use the pressure of falling water to propel turbines
Geothermal energy – heat from the beneath the crust heats steam that drives turbines

4. Tides & Wind Farms
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Tidal energy – moving water (tides) along the ocean floor propels turbine generators
e.g. Bay of Fundy, Nova Scotia
Wind energy – moving air (wind) along the ground propels turbine generators
e.g. wind farms in the Netherlands

5. Sunlight & Fuel Cells
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Solar energy – sunlight is converted into electric current by silicon-based solar cells
e.g. International Space Station
Fuel cells – chemicals continuously feed a chemical reaction that produces electricity
e.g. hydrogen + oxygen  water + electricity

6. Renewable or Not?
Last Slide
Renewable resources may be replaced naturally after a while
e.g. light, biomass, and geothermal heat
Non-renewable resources cannot be replaced or replenished if they are used up
e.g. coal, crude oil, and natural gas

7. Electricity and the Environment

8. Air Pollution Burning of fossil fuels results in pollutants
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Burning of fossil fuels results in pollutants
Coal power plants create airborne fly ash, which contains deadly mercury
Coal is now cleaned; fly ash is now captured
SO2, NOx, CO2 released during coal combustion causes acid rain
CO2 also causes enhanced greenhouse effect

9. Environmental Effect
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Strip-mining of coal may harm the natural environment
Oil and gas wells may release deadly gases
Steam turbines releases warm water into rivers and lakes; may harm organisms
Nuclear reactors produce radioactive wastes

10. Environmental Effect Hydro-electric dams flood river valleys
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Hydro-electric dams flood river valleys
Wind farms make large areas of land not useable for other purposes
Building solar cells makes harmful chemicals
Tidal generators displace marine organisms
Overall: alternatives harm the environment far less than traditional sources of energy

11. Conservation
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Higher demand for energy means higher consumption of energy resources
Lowering your energy use means you are making non-renewable resources last longer
More alternatives mean that non-renewable resources will last longer.

12. Sustainability
Last Slide
Sustainable energy use means making an energy resource last for a really long time
Personal decisions influence sustainability
We need to conserve our resources in order to sustain them over a long period of time.

13. Electrical Technology and Society

14. Benefits
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Electronic devices allow us to complete more tasks quickly and efficiently
Free time may be used for other pursuits

15. Drawbacks Technology can be too expensive
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Technology can be too expensive
Resources are needed to build technology
Sustainability is threatened
Old discarded technology creates waste

16. Computers We exist in the computer age
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We exist in the computer age
Computers speak in binary numbers (ones and zeroes)
Different technologies store and transmit computer information (CD’s, hard drives, etc.)

17. Information “Hackers” break into computer systems
Last Slide
“Hackers” break into computer systems
Misleading or “wrong” information on the internet
People feel bombarded by the information available
Computer viruses