Lesson 12 November 25 th, 2010

 The electricity used in most homes in Ontario is usually generated quite some distance away at some large scale electricity generation facility. The facilities are generally large scale products built by the government or businesses.

 The production of energy can be classified into two categories: 1. Non-renewable resources.  A resource that cannot be replaced once it is used up. 2. Renewable resources.  A resource that can be reused or replaced.

 In 1831, Michael Faraday, an English chemist and physicist, demonstrated that an electric current can be generated by moving a conducting wire through a magnetic field, a process called electromagnetic induction

 Electromagnetic induction is used to day to generate electricity in large-scale generators.  An apparatus that transforms the energy of motion into an electric current.  Magnets inside the generator are rotated by a turbine. The magnets spin coils of copper wires. This pulls electrons away from their atoms and creates a current in the copper wire.

 The current is sent through transmission lines to cities and towns.  The transmission lines and substations are known as an energy grid.

 In many areas, thermoelectric generating plants use a fuel such as coal or biomass to heat water to create high-pressure steam.

 Coal, oil, and natural gas are fossil fuels,  Organic matter of organisms that lived millions of years ago.  The chemical energy stored in the fuel is released as heat when it burns.

1. the fuel is burned to boil water to make steam 2. the steam makes a turbine spin 3. the spinning turbine turns a generator which produces electricity 4. the electricity goes to the transformers to produce the correct voltage

 Ontario’s electrical energy needs far surpass what hydroelectric and thermoelectric generators supply. Fifty-one percent of our electricity in Ontario is thermonuclear, which means it is produced by heat in nuclear power stations.

 In a nuclear reactor, atoms of a heavy element, usually uranium, are split in a chain reaction. This splitting, called nuclear fission, releases an enormous amount of energy.  The nuclear fission of just 1 kg of uranium is equivalent to burning about kg of coal. The energy released by the fission process is used to heat water to produce steam to turn a turbine.

 Most electricity generated in Canada is hydroelectricity, which means it is generated by harnessing the power of flowing water.  The water is directed through a channel called a penstock to a turbine with ridges around it. The water turns the turbine, which is connected to a generator

 60 % of Canada’s electricity is generated by hydroelectric

 Organic material made up of plant and animal waste.  Examples of biomass include wood, peat, straw, nut shells, sewage, and corn husks

 Organic waste decomposes to produce a gas called methane. The methane gas can be burned to boil water to make steam. The most common biomass material used today is wood waste from lumber and from pulp and paper industries.

 In some places in the world, water is naturally heated by hot rock deep in Earth’s crust and rises to the surface as hot water and steam

 Geothermal energy sources at or near Earth’s surface are hot enough to heat homes and other buildings. For generating electricity, hotter sources are needed. High-temperature geothermal sources are found deep in areas where there is volcanic activity.  19 % of Iceland’s power id generated by geothermal

 1839, French scientist Edmond Becquerel soaked two metal plates in an electricity-conducting solution. When exposed to sunlight, there is a small potential difference between the plates.  The sun is used to knock electrons off atoms. The electrons flow then creates a current.

 A solar farm includes arrays of mirrors that focus sunlight onto a liquid that is heated and used to turn water into steam to drive the turbines

 One of the world’s largest solar energy projects includes solar farms in Sarnia and Sault Ste. Marie and aims to produce enough electricity for about 9000 homes

 Wind turbines use the energy of moving air to spin their blades, which are connected to a generator  Wind energy currently provides about 1 percent of Ontario’s electricity, but it is one of the fastest-growing energy sources in the world.

 Tidal energy uses the energy of the gravitational pull of the Moon to fill reservoirs full of water which then turns turbines.  Research is being done tidal stream generators.  Ocean wave and Ocean thermal energy are also being looked into

SourceAdvantagesDisadvantages Fossil Fuels -Fossil fuel generating stations can quickly adjust to changes in demand -The technology for using these fuels is already in place -The burning of fossil fuels releases pollutants into the atmosphere and directly contributes to global warming. -Mining coal is hazardous to the workings and damages the environment

SourceAdvantagesDisadvantages Nuclea r -Nuclear power is inexpensive to produce -Produces enormous amounts of energy from very little fuel. -Waste is poisonous and radioactive and needs to be stored very carefully for hundreds or thousands of years -Nuclear plants are very costly to construct and maintain.

SourceAdvantagesDisadvantages Hydroel ectric -Large generating stations produce electricity inexpensively -Reservoirs may be used for flood control, irrigation, drinking water, and recreation -Small scale hydroelectric plants using the local rivers can be practical for some communities -There is a huge environmental impact when the dam is constructed, including flooding large areas of land, disruption or destruction of wildlife and fish habitat and migration routes, and displacement of Aboriginal communities. -Hydroelectric stations are very expensive to build

SourceAdvantagesDisadvantages Sunlig ht -Solar cell energy is a convenient source of energy for small appliances, such as calculator’s Solar energy is useful in remote areas. -Solar cell efficiency is low, so many photoelectric cells have to be used, which takes up large areas of land. -Solar energy is the most expensive energy source at present.

SourceAdvantagesDisadvantages Tides -Once tidal generating stations are built, tidal energy is very inexpensive. -Tides are more predictable than wind or sunlight -The environmental impact of marine life in area can be significant, due to changes in water level and water quality. -Tidal energy is suitable for few areas as it requires very high tides.

SourceAdvantagesDisadvantages Wind -Wind energy production does not produce greenhouse gases that contribute to global warming. -Farming and grazing can continue on land where wind turbines are located. -The wind does not always blow or remain constant. -Wind turbines can present barriers to bird movement, cause bird fatalities due to collisions with turbine blades, and can disturb breeding, wintering, and staging sites.

 Canada is the world’s largest producer of hydroelectricity, the fifth-largest producer of electricity in general, and the second-largest exporter of electricity.  - A large part of our electricity is generated using non-renewable resources

 - Renewable energy projects for generating electricity are under way or being planned.  To reduce our use of non-renewable resources, we have to find ways to use less electricity through technology and changing our usage habits.

 Sustainability means using resources at a rate that can be maintained indefinitely. With renewable energy methods, resources such as solar energy and wind are available indefinitely. We may never be able to achieve complete sustainability, but the decisions we make personally and as a society can move us closer to this goal

 An example of a personal decision would be to turn off the lights in your bedroom or classroom if you are the last person out of the room.

 Three Gorges: Potential Disaster or Good Choice?  Answer the questions and hand in