Electrical Energy Sources and Alternatives

Coal Energy Slide 2 of 6 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

Turbine Generators Slide 3 of 6 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

Tides & Wind Farms Slide 4 of 6 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

Sunlight & Fuel Cells Slide 5 of 6 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

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

Electricity and the Environment

Air Pollution Burning of fossil fuels results in pollutants Slide 2 of 6 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

Environmental Effect Slide 3 of 6 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

Environmental Effect Hydro-electric dams flood river valleys Slide 4 of 6 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

Conservation Slide 5 of 6 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.

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.

Electrical Technology and Society

Benefits Slide 2 of 5 Electronic devices allow us to complete more tasks quickly and efficiently Free time may be used for other pursuits

Drawbacks Technology can be too expensive Slide 3 of 5 Technology can be too expensive Resources are needed to build technology Sustainability is threatened Old discarded technology creates waste

Computers We exist in the computer age Slide 4 of 5 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.)

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