12.1 Renewable and Non-Renewable Energy Resources for...

Local Solutions to Generating ElectricityWhen you turn on the light in your bedroom, you are usingelectricity that was generated far from your home. A largehydroelectric dam, a coal-burning generating plant, or a nucleargenerating plant is probably the source of your electricity. In someareas of Ontario, the source is wind farms made up of giant windturbines. To build a hydroelectric dam or enough wind turbinesto generate electrical energy for a large number of people requiresa huge investment in money, people, and equipment. Usually,governments and businesses build these large-scale projects.

Coal and oil are non-renewable resources. A non-renewableresource is one that cannot be replaced once it is used up. However,in the past 10 years, governments have invested small-scale projectsthat use other sources of energy, such as the Sun, to generateelectrical energy. The Sun and the wind are renewable resources.A renewable resource is one that can be reused or replaced.

In some parts of Ontario and elsewhere in Canada, renewableenergy sources can be a practical alternative to non-renewable

474 UNIT D The Characteristics of Electricity

Here is a summary of what youwill learn in this section:

• Electrical generators transformthe energy of motion into anelectric current.

• Most electricity generated inCanada is from hydroelectric orthermoelectric sources.

• Other energy sources includebiomass, geothermal energy,sunlight, wind, and tides.

• There are both renewable andnon-renewable energy sources.

• Every energy source has bothpros and cons.

• We need to move towardsustainability in our use ofresources.

Renewable and Non-Renewable EnergyResources for Generating Electricity

Figure 12.1 Students in Elliot Lake helped install solar energy panels on their school forgenerating electricity.

12.1

Figure 12.2 Location of the town ofElliot Lake

Windsor

Sault Ste. Marie Sudbury

ThunderBay

Toronto

Ottawa

0 50 100 km

N

Elliot Lake

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resources for generating electrical energy to meet specificneeds in communities.

Elliot Lake Secondary School is one example of a smallrenewable energy project (Figure 12.1). Students at theschool proposed to the government that they would place12 solar panels and a wind turbine on the roof of theirschool. They pointed out that the electricity generated fromthese two energy sources would help provide electricity tothe school. The project also supported the community ofElliot Lake’s program to reduce its dependence on non-renewable energy sources such as coal and oil (Figure12.2). Impressed with the students’ ideas, the governmentof Ontario awarded them a $50 000 grant. Figure 12.1shows students at the school installing solar panels at theschool. Now the students also have work experience relatedto installing solar panels and wind turbines.

All over Ontario and Canada, communities aredeveloping small-scale projects to produce electrical energyusing renewable energy methods (Figure 12.3).

475We can reduce our electrical energy consumption and use renewable energy resources to produce electrical energy.

D25 Quick Lab

Renewable Energy Projects in Your Community

Renewable energy projects can be found all overOntario. Using print and electronic resources, youand your classmates will learn about examples ofthese projects in your community.

PurposeTo identify and describe the function of renewableenergy projects in your community

Procedure

1. Your teacher will provide summaries of projectsusing renewable resources for generating electricalenergy in your area or elsewhere in the province.

2. With a partner or small group, select one projectto work on.

3. Create a summary of the key features of the project— type of technology used, reason for the project,costs, and value to users and the community.

4. Present your findings to the class.

Questions

5. How many different kinds of renewable methodsfor generating electricity did you discover?

6. Are some methods of generating electricity morecommon than others? Why do you think this isthe case?

7. What do you think is one reason there are notmore renewable energy projects in yourcommunity?

Materials & Equipment• information summaries about renewable energy

projects

Figure 12.3 The GreenWorks Building at theKortright Conservation Centre in Torontogenerates electricity using solar energy. (© Toronto and Region Conservation, all rightsreserved)

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Generating ElectricityIn 1831, an English chemist and physicist named MichaelFaraday made an electrical discovery that changed the world(Figure 12.4). Faraday introduced a way to generate a steadysupply of large amounts of electricity. He demonstrated that anelectric current can be generated by moving a conducting wirethrough a magnetic field, a process called electromagneticinduction.

We use electromagnetic induction today to generate electricityin large-scale generators (Figure 12.5). Most generators do thesame job: they transform the energy of motion into an electriccurrent. The magnets inside a generator are rotated by a turbine,which is a machine that uses the flow of a fluid to turn a shaft.The magnets spin coils of copper wire. This pulls electrons awayfrom their atoms and creates a current flowing in the copper wire.

The current is sent through transmission lines to reach citiesand towns. The web of interconnections between generatingstations, substations, and users is called an energy grid or adistribution grid (Figure 12.6). Generating electricity starts witha spinning turbine and ends up at your wall socket. But wheredoes the energy come from to spin the turbine?


WORDS MATTER

A turbine converts steam or movingwater to mechanical energy usingpaddles or fins or even buckets. Theword “turbine” comes from the Latinturbo, meaning spinning top orwhirlwind.

Figure 12.4 Michael Faraday(1791–1867)

Figure 12.5 The electricity we use inour homes and schools is producedby massive coils of wire rotatingbetween magnets in hugegenerators, like this one inNanticoke, Ontario.

generating station

transmission line

underground power wires

transmission line

underground power wires

substation

Figure 12.6 An electric power gridtransfers energy from the generatingstations to the users. The whole gridis a complete circuit.

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During WritingUsing Water Power to Generate ElectricityMost electricity generated in Canada is hydroelectricity, whichmeans it is generated by harnessing the power of flowing water.Some hydroelectric stations in smaller communities use fast-flowing rivers to turn their turbines. Other hydroelectricstations, such as the ones at Niagara Falls, use the flow from awaterfall to turn their turbines (Figure 12.7).

Most communities do not have a waterfall, so a dam may bebuilt across a river to store water in a reservoir. The water is thendirected through a channel called a penstock to a turbine withridges around it (Figure 12.8). The water turns the turbine,which is connected to a generator.

WORDS MATTER

The prefix “hydro-” comes from theGreek word hudor, which meanswater.

Figure 12.7 The Sir Adam BeckGenerating Station at Niagara Falls

Show What You Know

As a writer, you want toconvince a reader that you knowyour topic. Add details, usefacts, and present evidence todemonstrate your knowledge.

transformer

generator

water flow

penstock

turbine

Figure 12.8 In a hydroelectric generating station, water flowsthrough a penstock. As it flows past the turbine, it causes theturbine to turn. The turning turbine is connected to thegenerator. The generator converts the energy from the turningmotion of the turbine to electrical energy.


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Using Heat to Generate ElectricityIf there are no waterfalls or rivers in your area, what mechanicalforce can be used to turn the turbines? One answer is steam. Inmany areas, thermoelectric generating plants use a fuel suchas coal or biomass to heat water to create high-pressure steam.

Fossil FuelsCoal, oil, and natural gas are fossil fuels, which means they wereproduced from the organic matter of organisms that lived millions ofyears ago. A fossil fuel, usually coal, is burned in a generator to boilwater. The steam is kept under great pressure in pipes, which allowsit to reach higher temperatures than normal. The high-pressuresteam strikes and pushes the blades on the turbine (Figure 12.9).

BiomassBiomass is organic material made up of plant and animal waste.Examples of biomass include wood, peat, straw, nut shells,sewage, and corn husks (Figure 12.10). In a biomass system, theorganic waste decomposes to produce a gas called methane. Themethane gas can be burned to boil water to make steam. The mostcommon biomass material used today is wood waste from lumberand from pulp and paper industries.


WORDS MATTER

The combining forms “therm-” and“thermo-” are from the Greek wordfor heat.

coal in combustion chamber

cooling tower

condenser

water

exhaust steam

transformergeneratorturbine

high-pressure steam

Figure 12.9 A coal-fired generating station

Figure 12.10 Corn husks are anexample of biomass that is burnedto boil water to make steam to turna turbine.

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Nuclear EnergyOntario requires a huge amount ofelectrical energy. We have a largepopulation and are a major centre ofmanufacturing. Our electrical energyneeds far surpass what hydroelectric andthermoelectric generators supply. Fifty-one percent of our electricity in Ontario isthermonuclear, which means it isproduced by heat in nuclear powerstations (Figure 12.11).

In a nuclear reactor, atoms of a heavyelement, usually uranium, are split in achain reaction. This splitting, callednuclear fission, releases an enormous amount of energy. Thenuclear fission of just 1 kg of uranium is equivalent to burningabout 50 000 kg of coal. The energy released by the fission processis used to heat water to produce steam to turn a turbine.

Geothermal EnergyIn some places in the world, water is naturally heated by hot rockdeep in Earth’s crust and rises to the surface as hot water and steam(Figure 12.12). The energy from this hot water and steam is calledgeothermal energy. Geothermal energy sources at or near Earth’ssurface are hot enough to heat homes and other buildings. Forgenerating electricity, hotter sources are needed.

High-temperature geothermal sources are found deep in areaswhere there is volcanic activity. Iceland has active volcanoes andmany hot springs. It uses geothermal energy to produce 19 percentof its electricity. In Canada, geothermal sources hot enough to beused to drive turbines for electricity generation are located inBritish Columbia. Tests are under way there to determine how touse geothermal sources cost effectively.


Figure 12.12 A hot spring is anexample of geothermal energy.

Learning Checkpoint

1. What is a non-renewable resource?

2. What does a generator do?

3. What is a turbine?

4. What source does most of Canada’s electricity come from?

5. What is a fossil fuel?

Figure 12.11 The Pickering Nuclear Power Plant is one of three nucleargenerating stations in Ontario.

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Other Energy SourcesThere are other energy sources that can be used to generateelectricity. As different technologies continue to be developed andrefined, our ability to use these sources economically increases.

Solar EnergyMany people think solar cells are a new technology, but the rootsof this invention go back to 1839, when French scientist EdmondBecquerel soaked two metal plates in an electricity-conductingsolution. When Becquerel exposed one of the plates to sunlight,he could detect a small potential difference between the plates. Hehad invented the first solar cell. Scientists now make solar cellsusing silicon (Figure 12.13).

Solar modules (several cells connected together) and arrays(several modules) have many uses, including poweringcalculators, lights in telephone booths, and the InternationalSpace Station. A solar farm includes arrays of mirrors that focussunlight onto a liquid that is heated and used to turn water intosteam to drive the turbines (Figure 12.14). One of the world’slargest solar energy projects includes solar farms in Sarnia andSault Ste. Marie and aims to produce enough electricity for about9000 homes.


AB

CD

E

F

sunlight

A Protective cover glassB Antireflective coating to let light in and trap itC Metal contact grid to collect electrons for circuitD Silicon layer to release electronsE Silicon layer to absorb electronsF Metal contact grid to collect electrons from circuit

Figure 12.13 A solar cell hasspecially treated layers that createcurrent when exposed to sunlight.

Figure 12.14 The mirrors in thissolar array focus heat from the Sunon a container that is part of asystem to turn water into steam.

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Wind EnergyWind turbines use the energy of moving air to spin their blades,which are connected to a generator (Figure 12.15). The amountof energy a wind turbine generates depends on how fast the windis blowing, with approximately 10 km per hour being theminimum for power generation.

In Ontario, the wind blows strongly enough, on average, about20 percent of the time, but in some areas of Canada and theworld, winds are stronger and more consistent. Wind energycurrently provides about 1 percent of Ontario’s electricity, but itis one of the fastest-growing energy sources in the world.

Tidal EnergyTidal energy uses the energy of the gravitational pull of theMoon. North America’s only tidal power generating station is inAnnapolis Royal, in Nova Scotia, where the powerful tides of theBay of Fundy spin its turbines (Figure 12.16). The stationprovides enough electricity for about 4500 homes.

Tests are under way in British Columbia and Nova Scotia for apromising new technology called a tidal stream generator, whichworks like an underwater windmill. Other marine energy sourcesthat are being tested include ocean wave energy and oceanthermal energy.


Figure 12.15 A wind farm nearShelburne, Ontario

Figure 12.16 This tidal power station in Nova Scotia generates electricity by using theenergy of the water as it rises and falls in the daily cycle of tides.

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Comparing Methods ofGenerating ElectricityEnergy sources for generating electricity canbe grouped into two broad categories. Non-renewable energy sources are sources that arelimited and cannot be renewed naturally.Fossil fuels (natural gas, propane, coal, andpetroleum) are non-renewable sources, as isuranium. Once these materials are used up,they cannot be replaced.

Renewable energy sources are sources thatcan be replenished by natural processes in arelatively short time, such as sunlight, wind,tides, and waves. Biomass is a renewablesource if the trees or other plants thatproduce it are properly managed.

A few of the advantages anddisadvantages of using different energysources are summarized in Table 12.1 andTable 12.2. A comparison of the approximatecosts of using each source is shown in Figure 12.17.


Figure 12.17 Relative costs of electricity generation technologies

Source Some Advantages Some Disadvantages

Fossil fuels – Fossil fuel generatingstations can quickly adjustto changes in electricitydemand.

– The technology for usingthese fuels is already inplace.

– The burning of fossil fuelsreleases pollutants into theatmosphere and directlycontributes to global warming.

– Mining coal is hazardous toworkers and damages theenvironment.

Nuclear – Nuclear power isinexpensive to produce.

– Nuclear power producesenormous amounts ofenergy from very little fuel.

– Nuclear waste is poisonousand radioactive and needsto be stored very carefullyfor hundreds or thousandsof years.

– Nuclear plants are verycostly to construct and tomaintain.

Table 12.1 Some Advantages and Disadvantages of Non-Renewable Sourcesfor Electricity Generation

0

10

20

30

40

60

50

80

70

nucle

ar

Relative Costs of Electricity Generation Technologies(Canadian cents per kilowatt hour, 2003)

coal gas

biom

ass

landf

ill g

as

micr

o hy

dro

small

hyd

ro

large

hyd

ro

solar

pho

tovo

ltaic

wind

geot

herm

al

wave

and

mar

ine

SOURCE: CERI, Relative Costs of Electricity Generation Technologies, September 2006

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Source Some Advantages Some Disadvantages

Flowing water(hydroelectricity)

– Large hydroelectricgenerating stations produceelectricity inexpensively.

– Reservoirs may be used forflood control, irrigation,drinking water, andrecreation.

– Small-scale hydroelectricplants using local rivers can be practical for somecommunities (Figure12.18).

– There is a hugeenvironmental impact whena dam is constructed,including flooding largeareas of land, disruption ordestruction of wildlife andfish habitat and migrationroutes, and displacement ofAboriginal and othercommunities.

– Hydroelectric stations arevery expensive to build.

Sunlight – Solar cell energy is aconvenient source ofenergy for smallappliances, such ascalculators.

– Solar energy is useful inremote areas.

– Solar cell efficiency is low,so many photoelectric cellshave to be used, whichtakes up large areas ofland.

– Solar energy is the mostexpensive energy source atpresent.

Tides – Once tidal generatingstations are built, tidalenergy is very inexpensive.

– Tides are more predictablethan wind or sunlight.

– The environmental impacton marine life in area canbe significant, due tochanges in water level andwater quality.

– Tidal energy is suitable forfew areas as it requires veryhigh tides.

Wind – Wind energy productiondoes not producegreenhouse gases thatcontribute to globalwarming.

– Farming and grazing cancontinue on land wherewind turbines are located.

– The wind does not alwaysblow or remain constant.

– Wind turbines can presentbarriers to bird movement,cause bird fatalities due tocollisions with turbineblades, and can disturbbreeding, wintering, andstaging sites.

Table 12.2 Some Advantages and Disadvantages of Using Renewable Sourcesfor Electricity Generation

Learning Checkpoint

1. What are three applications of solar cells?

2. What does a wind turbine do?

3. What is one of the fastest-growing energy sources in the world?

4. How is electricity generated from tides?

5. How is a renewable energy source different from a non-renewable energysource?

Suggested STSE Activity •D26 Decision-Making Analysis CaseStudy on page 486

Figure 12.18 Small-scalehydroelectric generating stationscan be a local source of electricalenergy.

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Electrical Energy Production in CanadaCanada is the world’s largest producer of hydroelectricity, the fifth-largest producer of electricity in general, and the second-largest exporter of electricity.

However, we need to be aware of the environmentalimplications of using non-renewable resources. As Figure 12.19shows, a large part of our electricity is generated using non-renewable resources. These resources include coal, uranium(for nuclear energy), oil, and gas. We must decide how to make atransition to using more renewable resources. We need electricity,but we also need to generate it wisely.

All of our energy sources are important to Canada becausethey provide us with flexibility and energy security and help us tobecome self-sufficient. For example, at one time, Prince EdwardIsland was completely dependent on outside sources forelectricity because it does not have fossil fuels, hydroelectricity, ornuclear power. However, the island now produces 18 percent ofits electricity from wind energy and has become the first place inNorth America to offer a guaranteed price to anyone — even ahomeowner — who produces electricity from wind power.

In Ontario and across Canada, renewable energy projects forgenerating electricity are under way or being planned. However,as you can see in Figure 12.19, this type of electricity generationproduced only 0.6 percent of our electricity in 2007. It cannotreplace our use of non-renewable energy resources for now. Toreduce our use of non-renewable resources, we have to find ways to use less electricity through technology and changing ourusage habits.


hydro nuclear

coal oil and gas

other

Electricity Generated in Canada 2007

4.014.6

20.7

0.6

60.1

Figure 12.19 Methods of electricity generation in Canada

Hydrogen may be our fuel ofchoice in the future. It can beburned like other fuels orconverted into electricity in fuelcells. Find out how the mostabundant element in the universecan be put to use for our electricalneeds. Start your research atScienceSource.

Take It Further

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A Sustainable ChoiceChoosing the right methods for generating electricity meansfinding sustainable solutions. Sustainability means usingresources at a rate that can be maintained indefinitely. If we donot achieve sustainable energy use, future generations in Ontariomay not be able to support themselves.

A sustainable approach sometimes requires a different way ofusing resources. Sustainability may mean no longer using non-renewable resources because they cannot be maintainedindefinitely. In the past, fossil fuels were used up as quickly aspossible to earn money and satisfy consumer demand. We need touse our resources in a way that makes them available over alonger period of time. With renewable energy methods, resourcessuch as solar energy and wind are available indefinitely.

Figure 12.20 shows the main methods worldwide forgenerating electricity in 2007. Coal, oil, and gas account for 66.6 percent of electricity production. These three methods areusing non-renewable resources. The other three methods, hydro,nuclear, and other account, for 33.4 percent of the production.Hydro and other methods use renewable energy sources.

We may never be able to achieve complete sustainability, but thedecisions we make personally and as a society can move us closer tothis goal. An example of a personal decision would be to turn off thelights in your bedroom or classroom if you are the last person out ofthe room. This small action would save on electrical use. As you getolder, you may make bigger decisions such as adding solar panels toa house you live in (Figure 12.21). Decisions such as thesedemonstrate you are keeping the goal of sustainability in mind.


Electricity Generated Worldwide in 2007

2.2 16.019.7

6.6

15.2

40.3

hydro nuclear

coal oil other

gas

Figure 12.20 How the world generates electricity. This graph could become very differentduring your lifetime.

Figure 12.21 The people who live inthis house are using solar panels toheat their water. This reduces theirelectricity use.

Suggested Activity •D27 Decision-Making Analysis on page 488

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CASE STUDY

Decision-Making Analysis

IssueThe Three Gorges Dam on the Yangtze River inChina is the world’s largest hydroelectric generatingstation (Figure 12.22). The dam is 2.3 km long and101 m high, with a reservoir that floods 632 km2 ofland. The dam provides electricity to nine provincesin China. Is the electricity the dam provides worth theproblems it causes?

Background InformationTwo students, Bassim and Kara, have beenresearching the Three Gorges Dam to find out thecosts and benefits of this huge hydroelectric project.The more they have learned about the dam, themore they are convinced of their own viewpoints.

Kara’s Viewpoint: In Favour of the Dam

The Three Gorges Dam is a good example of China’scommitment to using renewable resources toincrease its production of electricity.

• Until recently, 82 percent of China’s electricitywas generated in coal-burning stations. ThreeGorges could allow China to reduce coalconsumption by 31 million tonnes per year,

so millions of tonnes of greenhouse gasesand pollutants will not be created.

• China plans to increase electricity fromrenewable resources from 7.2 percent to 15 percent by 2020. A series of smallerdams being built on the Yangtze will reducesilt and help to maximize the efficiency ofthe Three Gorges Dam.

• China is taking steps to minimizeenvironmental damage. Billions of dollarsalready have been spent in water clean-upprojects and in preventing landslides.

• The potential of the dam to prevent orreduce flooding for the millions of residentsdownstream means that far more lives andproperty can be saved than were lost due tothe building of the dam.

• As well as providing flood control, the damhas improved navigation so that large shipscan travel farther upriver, improving theeconomy of the area.

• The people of China need more electricity,and they have made a good choice in usingrenewable sources.

SKILLS YOU WILL USE■ Drawing conclusions■ Justifying conclusions

Three Gorges: Potential Disaster or Good Choice?

STSED26 Skills Reference 4

Figure 12.22 The Three Gorges Dam provides electricity to nine Chinese provinces. However, it has negatively affectedmillions of people who used to live where its reservoir now lies.

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Decision-Making Analysis (continued)

Bassim’s Viewpoint: Opposed to the Dam The Three Gorges Dam is a social and environmentaldisaster and should not have been built. Millions ofpeople live downstream from the dam and are indanger if the dam should ever fail.

• Over 1.2 million people were forced out of theirhomes so that their land could be flooded by thereservoir. Many of these people have had tomove a second time due to an increase inlandslides caused by filling the reservoir. Fourmillion people are being encouraged to movebefore 2020.

• As well as submerging homes and more than1300 archaeological sites, the reservoir alsosubmerged factories, mines, and wastedumps. All the chemicals and other waste atthose sites now contribute to the pollution ofthe reservoir. Also, only about 65 percent ofthe water flowing into the reservoir is treated,adding to the pollution and the possibility ofdiseases carried by water.

• The dam sits on a seismic fault, and there isdanger of increased earthquakes and landslides.Much of the silt that the river used to carry allthe way down to the coast now settles in thereservoir and reduces the effectiveness of thedam. Cities such as Shanghai that are fardownstream no longer have silt deposited to helpbuild up their banks and may soon suffer fromhuge erosion problems.

• The changes in water flow affect downstream fishpopulations. These changes have resulted in theextinction of the Yangtze River dolphin and may beharming the populations of critically endangeredSiberian cranes (Figures 12.23 and 12.24).

Analyze and Evaluate

1. Read both students’ viewpoints. Which studentdo you think presents a stronger case? Why?

2. Choose one of the following roles. Prepare apresentation from that perspective, defending apossible course of action for an internationalenergy conference.• relocated villager • wildlife expert• government official • industrialist• Shanghai citizen • geologist • citizen of province receiving electricity from

the dam

Skill Practice

3. What is your conclusion about whether theelectricity the dam provides is worth theproblems it causes? Explain and justify yourconclusion.

STSED26

Figure 12.23 Siberian cranesare endangered birds that havebeen negatively affected by thedam’s construction.

Figure 12.24 The Yangtze River dolphin has becomeextinct since the construction of the dam.

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Decision-Making Analysis

IssueEnvironmentally, it makes sense to close coal-burning generating stations. Open-pit mining of coalscars the landscape. Burning coal releases pollutantsinto the air that cause acid rain. However, it does notmake sense economically for now. The huge amountof power lost to the grid would have to be replaced.The job losses would have a devastating effect onlocal economies. What recommendations would youmake to a community that relies on burning coal forelectricity generation?

Background InformationEvery method of electricity generation hasadvantages and disadvantages. For example, theoperation of wind farms along Lake Huron produceselectricity from a renewable source (Figure 12.25).This reduces dependence on non-renewable sourcesof electricity. However, the wind farms produce noiseand visual pollution, affect local animal life, andreduce the amount of land available for agriculture.

Your goal is to identify some of the social,economic, and environmental implications ofelectricity production in a community in Ontario. Youwill research the social, economic, andenvironmental effects of one method of electricitygeneration that is different from the main method

being used now in the community. You will alsocompare your proposed method to the presentmethod. Then, you will make a presentation insupport of your choice.

Analyze and Evaluate

1. Meet with your group members to discuss therole each member will play in researching,formatting, and presenting your information.Create a list of questions and key words that willhelp direct your research.

2. Web 2.0 Work together to decide on a format forpresenting your research. Develop your group’sresearch as a Wiki, a presentation, a video, or apodcast. For support, go to ScienceSource.

3. ScienceSource Conduct your research online.Copy and complete the chart below as part ofyour research.

4. What percentage of the energy produced shouldcome from your proposed method? Explain.

Skill Practice

5. (a) What challenges did you have in researchingthe information you needed?

(b) How did you overcome the challenges?

SKILLS YOU WILL USE■ Gathering, organizing, and

recording relevant informationfrom research

■ Using appropriate formats tocommunicate resultsProducing Electricity in an Ontario Community

D27 Skills Reference 4

Figure 12.25 Wind farms have to be placed where the windis strong and steady enough to generate electricity costeffectively.

PresentMethod

ProposedMethod

Economic- cost of producing electricity

per kW•h

Environmental- hazardous substances used

or produced and their effectson surrounding ecosystem

Social- effects of emissions on

human health

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Key Concept Review1. What is the function of a generator?

2. What does “hydroelectricity” mean?

3. What are four methods of generatingelectricity that use heat?

4. Explain how a solar cell produceselectricity.

5. What are two different ways to make use ofthe tides to generate electricity?

6. (a) What is the difference betweenrenewable and non-renewable sourcesof energy?

(b) Create a chart that categorizes differentenergy sources as either renewable ornon-renewable.

7. (a) What is the source of most of theelectricity generated in Ontario?

(b) What is the source of most of theelectricity generated in Canada?

8. The photos below show the type of solarcells that are installed on the “wings” of theInternational Space Station. Why are solarcells used to generate electricity onspacecraft?

Connect Your Understanding9. Compare the generation of electricity using

coal with hydroelectric generation.

(a) How are the two methods similar?

(b) How are the two methods different?

10. Why does an electrical generating stationnot use batteries to generate electricity?

11. Suppose that residents of a remotecommunity in northern Ontario decide touse wood as their primary energy source forheating the boiler of the community’selectrical generator. They cut down all thetrees nearby and stockpile the wood, readyfor use.

(a) What are the advantages anddisadvantages of their solution for theirenergy needs?

(b) What recommendations would youmake to ensure that this community hasa reliable long-term energy supply?

Reflection12. (a) What information about electricity

generation did you learn in this sectionthat you did not know before?

(b) What are two questions that you haveabout electricity generation in Canada?

For more questions, go to ScienceSource.

12.1 CHECK and REFLECT

Question 8The International Space Station (a) uses 2500 m2 of solar cells (b) to generate itselectricity.

(a)

(b)

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