1. Using Electrical Energy Affects Society & the Environment

2. Ideally…  Human beings will balance the benefits of using electricity with the need to conserve resources.  Currently, about 65% of all electrical power is generated by burning oil, coal, or natural gas.

3. Called “fossil fuels”

4. How good are humans at balancing?

7. Coal  Most of the fossil fuel used in power plants is coal.  Alberta has large and “easy to excavate” coal deposits.  Coal contains a lot of stored energy. Burning 1kg produces enough thermal energy to boil about 1/3 of a bathtub full of water.

9. Nuclear Reactors  Burning fossil fuels not the only way to provide heat for a steam-powered generator.  In Ontario, USA, and parts of Europe, nuclear reactors are used.  The way it works: Atoms of a heavy element, usually uranium, are split in a chain reaction.

10. Nuclear Fission  This splitting is called nuclear fission, and releases an enormous amount of energy.

11. Chernobyl

12. Geothermal Energy  Heat from Earth’s core can also be used to generate electricity.

13. Biomass  Biodegradable waste is buried in landfills.  When it decomposes, it produces combustible gases that can be collected and used as fuel for steam-driven generators.  “Waste heat” from manufacturing processes can be used to generate electricity. Making double use of energy in this way is called cogeneration.

14. Hydro-electric Power  20% of world’s electricity is generated by capturing the energy of falling water.

16. Alternative Energy Sources  Tides: moving water from tides can also power turbines that run generators.  Tide comes in, water is trapped in a reservoir, and then let out past turbines.  Not a lot in the world; difficulty in finding suitable locations. One in Nova Scotia- large tides in Bay of Fundy.

17. High Tide/Low Tide

19. Waves  Can be used to generate electricity too.

20. Wind  The amount of electricity a single windmill can generate is limited, but a number of wind-power generators can be connected together to form “wind farms”.

21. Sunlight- Solar Cells  Solar modules (several cells connected together) and arrays (several modules connected together) are used to power everything from calculators to spacecraft.  1839, French scientist Becquerel soaked 2 metal places in an electricity-conducting solution and when he exposed them to sunlight, detected a small voltage.

24. Batteries  Recently, a lot of research has been done to develop fuel cells.  These are batteries that generate electricity directly from a chemical reaction with a fuel such as hydrogen.  More fuel is added as electricity is produced, so the cell is not used up as a regular cell would be.

25. Energy Renewable Resource  Wind, tidal energy, solar energy, geothermal energy, biomass.  Trees if managed correctly.  A resource that can be renewed or replenished in a relatively short period of time. Nonrenewable Resource  Coal- can’t be replaced as it is used up.  Any fossil fuel (oil and natural gas) when it is used up, is gone forever.

26. Electricity & the Environment  Every method of generating electricity affects the environment.

28. Fly Ash  Airborne ash that is carried up the smokestack of a power plant and escapes into the atmosphere.  Contains mercury, a poisonous metal that can damage the nervous system.  Sulfur dioxide (causes acid rain & air pollution), Nitrogen oxides (cause air pollution) and Carbon dioxide (major cause of global warming) are also released into the air when coal is burned.

29. Other effects to the environment  Strip Mining: Removes all plants and animals from large areas of land.  Oil & Gas Wells: Some deposits of oil and gas contain poisonous gases, and chemicals can be released into the environment.  Steam turbines often release warm water into lakes and rivers. The resulting increase in water temperature can kill fish and other life.

30. “Green” sources of energy  Wind, tide, solar, and geothermal- harm the environment much less than fossil fuels do.  Even though nonrenewable fossil-fuel supplies will last for your lifetime, conserving them & limiting demand, as well as developing alternate energy sources, will cut down on pollution.

31. Sustainable  Sustainability means using resources at a rate that can be maintained indefinitely (forever!).

32. Electrical Technology & Society Benefits  Improved standard of living- for example- used to take a lot of hard work to complete the laundry  Now, machines do the washing, rinsing, and drying. Drawbacks  Obsolete devices discarded as waste.  Resources needed to manufacture and operate devices.  Too expensive for developing countries to use. Some people excluded from benefits of advancements.

33. Computers & Information  Computers convert all information to, even audio and video signals, into numbers and then perform calculations with numbers.  Computers use binary numbers, numbers with ones and zeros.

34. Computers & Electricity  Different techniques store & transmit information, but all use electrical current.  CD: a photodetector convers light pulses into electrical pulses; produces a digital signal with the same sequence of ones and zeros.  Hard Drive: Electric pulses are sent to an arm with read/write heads. Electrical signals control all the functions of a computer.

35. Electrical Transmission of Information  Information is now cheaper to store, easier to find, and much more compact.  A single DVD can store more information than a whole set of encyclopedias.

36. Concerns?  Access to technology: Some countries are too poor to establish the infrastructure necessary to connect computers and transmit information.  Privacy: Data transmission not always secure; “Hackers” attempt to break into networks to steal information or cause damage.

37. Concerns?  Trust: With huge volumes of information, some of it is wrong or misleading.  Information Overload: It’s increasingly difficult to get the info you need. Search engines help, but all work in different ways, and in ways that are not always helpful (popular sites vs useful sites).