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Get Energised!Teachers’ Guide

3Horizontal axis wind turbine

Teachers’ GuideThis guide helps teachers and pupils to apply classroom physics to explore a real-life challenge – renewable energy. It outlines different methods of generating renewable energy, and examines the Scottish context for each one. The guide includes Teachers’ notes and ideas for further reading and 5 Pupils challenge sheets for use in class.

Contents

Teachers’ notes 2

Get Energised! Curriculum links 2

Renewable Energy in Scotland 2

Hydroelectric Power 5

Solar Power 8

Wind Power 12

Wave Power 16

Further sources 19

Pupil Challenges 21

Hydro Challenge 23

Solar Challenge 29

Wind Challenge 35

Wave Challenge 39

Get Energised!

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Get Energised! Curriculum links

Topic Curriculum links

Hydroelectric PowerNat 3 – Energy sources, ElectricityNat 4 – Generation of electricity Nat 5 – Conservation of energy, Electrical power

Solar PowerNat 3 – Electricity, Solar systemNat 4 – Generation of electricity, CosmologyNat 5 – Conservation of energy, Electrical power

Wind PowerNat 3 – Energy sources, Electricity, Solar SystemNat 4 – Generation of electricity Nat 5 – Conservation of energy, Electrical power

Wave PowerNat 3 – Energy sources, Electricity, Solar SystemNat 4 – Generation of electricity Nat 5 – Conservation of energy, Electrical power

Renewable Energy in ScotlandThe Scottish government has a target of generating 100% of Scotland’s electricity demand from renewable sources by the year 2020.

Renewable electricity is generated from sources such as wind, tides, waves and sunlight. Unlike fossil fuels, these are sources which will not be depleted if we use them to generate electricity. It is estimated that in 2012 just under 20% of the world’s electricity consumption came from a renewable source.

In 2012 just over 40% of electricity consumed in Scotland was from renewable sources, in 2011 it was over 36% and in 2010 it was around 24%. Scotland generates more electricity than it uses and just over a quarter of the energy produced was exported.

The National Grid

The electricity generated by these renewable sources is moved to where it is needed on the National Grid. It connects the places that generate electricity (e.g. hydroelectric power stations, wind farms) to homes and businesses. In recent years individuals and communities have been generating their own electricity from items such as solar panels or wind turbines. These are also connected and these people can earn money for the electricity they don’t use.

In order to move electricity to where it is needed, the voltage is increased from around 1-30 kilo Volts to hundreds of kilo Volts. It is then stepped back down again for use when it reaches its destination. By increasing the voltage, the losses due to resistance are limited.

Measuring Output

The output of power stations and individual items such as solar panels and wind turbines can be measured in terms of energy or power:

• Ameasureofenergycommonlyusedbycompaniestomakeachargeforelectricityuseiskilo Watt hours, kWh. One unit of energy is 1 kWh = 3.6 Megajoules.

• ThepowerforawindfarmorpowerstationcanbelistedintermsofkiloWatts,kW(1000W), MegaWatts, MW (1,000 kW) or GigaWatts, GW (1000 MW). For example, Whitelee Wind Farm near Glasgow has a capacity of 539 MW and is one of the largest in Europe with over 200 turbines.

The capacity is the maximum potential power of the type of technology used for electricity generation.

• Whenthecapacityforasiteisdiscusseditisimportanttorememberthattheactualpowerand energy produced could be lower than the capacity due to varying local conditions.

• Forexample,windturbineswillnotbeoperatingattheirmaximum24hoursaday.Theiroperation will depend on the wind speed each day.

Efficiency

When electricity is generated, the process is not 100% efficient. For example, not all of the kinetic energy in the wind is converted to electricity by the wind turbine. Energy is lost through friction, heat and noise as the mechanical components in the wind turbine move.

Efficiency (%) = P out ×100

P in

Anestimateofefficienciesfordifferenttypesofelectricitygenerationcanbefoundbelow.Theefficiency level can vary between sites using the same type of generation. For example, a newer wind farm will have better technology than an older site.

SSE Power D

istribution

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Non-renewable source:

ItemInstalled Capacity (2012) World-wide (WW)Scotland (S)

Source of loss Type of loss Efficiency

Coal fired power station

20000 GW (WW)

24 GW (S)

Waste heat is produced as part of the process and is released into a cooling tower or is used to heat nearby buildings

Heat 33%

Nuclear power station

3700 GW (WW)

26 GW (S)

Like a coal fired power station, not all heat can be used to produce electricity and some is released

Heat 40%

Renewable source:

ItemInstalled Capacity (2012) World-wide (WW)Scotland (S)

Source of loss Type of loss Efficiency

Wind Farm290 GW (WW)

2 GW

Heat and noise of mechanical parts, wind is not constant so amount of electricity generated varies

Heat

Noise30%

Solar power100 GW (WW)

100 MW (S)

Due to their design and construction, panels cannot produce electricity from all wavelengths of light falling on it, e.g. ultraviolet or infrared

Type of material (size of band gap)

22%

Hydroelectric power

990 GW (WW)

1.5 GW (S)

Heat and noise of mechanical parts. Efficiency is higher than wind, for example, due to the consistent source of water to turn the turbines

Heat

Noise80-90%

Wave power0.5 GW

Schemes still under development in Scotland

The National Grid:

Item Source of loss Type of loss Efficiency

Electricity transmission line

The loss down to the resistance of the cable. The resistance depends on the distance the electricity is transferred and the current

Heat 95%

The following sections explore four different sectors of renewable electricity generation.

Hydroelectric PowerHydroelectric power is used in Scotland because of the natural geography of the land.

• Inordertogenerateelectricity,waterisdroppedfromaheighttodriveturbines. It has gravitational potential energy and gravity then pulls the water down when the flow is released.

• Thekineticenergyofthewateristransferredintomechanicalenergyintheturbine.

• Theresultisthegenerationofelectricityastheturbinedrivesagenerator.

• Itisaveryefficientprocess,with80-90%oftheenergyfromthemovingwaterbeingused to generate electricity.

Hydroelectric power station

Turbines

Hydroelectric power stations can be described based on the value of their “head”. This is a measure of the distance between where the water is stored and where it will end up once it has passed the turbines.

• Togenerateelectricity,thewaterflowiscontrolledonitswaytotheturbines.

• Thechoiceofturbinedoesnotdependonthewaterflowbutontheheadofthesite.

• Therearemorethan80hydroelectricpowerstationsinScotland,allwithdifferentvaluesfor the head and in them are many generations of turbine technology.

High-level reservoir

Low-level loch

Height

Water flow

Turbines andelectrical generators

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In general, there are two different kinds of turbines: impulse and reaction.

Impulse:

• Thebladesofanimpulseturbinearedrivenbyawaterjet.

• Thewaterflowisconcentratedthroughanozzle,whichisthenfiredatthebladesandthepressure from the water is constant. Newton’s second law can be called on to describe the behaviour of this turbine.

• Thistypeofturbineisgenerallyusedwhenthereisahighheadofover300m.

Reaction:

• Areactionturbinehastobefullysealedasthewaterflowsthroughtheturbine,causingtheblades to spin.

• TheoperationofthisturbinefallsunderNewton’sthirdlaw:foreveryactionthereisanequal and opposite reaction.

• Incaseswheretheheadisclassedasbeinglowormedium(upto300m)thereactionturbine tends to be used.

Types of power stations

There are different kinds of hydroelectric power stations. Each of the following methods is used to generate electricity in Scotland:

1. Pumpedstorage(CruachanDamatLochAweandFoyersintheHighlandsaretheonlytwoin Scotland)

• Waterflowsfromaheightanddrivesturbines.

• Thesesitesusespecialturbinesthatcanoperateinreversetopumpthewaterbackupto a height.

• Thisoperationusuallytakesplaceatnighttimewhenthereismuchlessdemandforelectricity use.

• Pumpedstorageisthoughtofasawaytostoreenergyinthegrid.Electricityisneeded to drive the pumps to put the water back at a height, but if it was not used for this purpose then it would most likely be unused. It then means that the next day when demand is at its highest, the water flow back down resumes and electricity is generated.

2. Run-of-river (as seen in the Bonnington and Stonebyres power stations near Lanark)

In order to drive turbines, these power stations divert water from a river. Once the water has passedthroughthepowerstationitisreturnedtotheriver.Asmalldamisusedtoregulatethe water flow to ensure a minimum level is reached for the turbines to operate.

3. Dams (Glendoe Hydro scheme near Loch Ness)

Adamisusedtocollectwaterinareservoir.Thereisthenapipeorchannelfromthedamthat feeds the water through into the turbine.

Advantages and Disadvantages

Some advantages Some disadvantages

• NoCO2 emissions once installed

• Reasonablylowmaintenancecosts

• Theelectricitygenerationisnotnecessarilyconstantand is often dependent on the weather or season

• Mosthydroelectricpowerstationshavenowayofstoring their output for when it is needed most.

• Expensivetobuild

• Dependingonthesite,therecanbeanextensiveimpact to local wildlife if a new reservoir is required as this means flooding of a large area. Infrastructure (roads and buildings) will need to be installed to maintain the site and this too will have an effect on the local environment

An impulse turbine

A Reaction turbine

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Solar PowerThe Sun is our ultimate source of energy on Earth and as such we want to harness as much of its power as possible. The Sun can provide use with a huge amount of power to generate electricity with. We have developed ways to harness this power, but more progress needs to be made in reducing the cost for it to be more widely used as a method to generate electricity.

The sunlight that reaches the surface of the Earth is measured in Watts/m2. The estimated split between the wavelengths is (when the Sun is at its highest point in the sky or zenith):

Total at the surface 1000 W/m2

Infrared 52%, 525 W/m2

Visible 45%, 445 W/m2

Ultraviolet 3%, 30 W/m2

The Earth is in constant motion around the Sun, but the Earth is tilted, meaning that our orientationtotheSunchangesthroughoutourtravels.Acrosstheyearthisisreflectedinthedifferent seasons. The height of the Sun in the sky changes and the angle of the Sun’s rays vary too.

Paths of the sun

The figures below show the angle of the sun’s rays across the seasons.

Winter

Spring

Summer

Autumn

Summer

Autumn

Spring

Winter

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Solar Panels

• SolarpanelscollectlightfromtheSunanduseittogenerateelectricity.

• Thepanelsneedtobeplacedtogatherasmuchlightaspossible.Youwilloftenseesolarpanels on the south facing roof of houses to take advantage of as much sunlight as possible. If they are not on buildings then they will usually be placed at an angle.

Solar panels

• Oftenmadefromsilicon,aphotovoltaiccellinasolarpanelusesenergyfromtheSuntogenerate electricity through the photoelectric effect.

• Whenthelighthitsthepanel,thephotonsinthelightareabsorbedbythesilicon.Thesephotons cause electrons to be separated from their atoms and a current begins to flow.

• Manyfactorscanaffecthowasolarpanelworks:

– Some will be directly related to the way the panel is constructed, for example the material used.

– The Sun emits across a range of wavelengths in the electromagnetic spectrum, but a solar panel cannot use 100% of energy emitted.

– Other aspects will depend on local conditions once the panel is installed: for example the number of daylight hours and the weather.

Solar in Scotland

• TheuseofsolarpanelsisincreasinginScotland.Eventhoughtherearefewlarge-scalesolar schemes, many individual homes, businesses and public buildings have solar panels installed.

• Moreandmorepanelswillbeinstalledinthecomingyearsasthepriceofinstallationgoesdown.Asthenumbersofpanelsmanufacturedincreases,thecostgoesdown.

• Afeed-intariffispaidtothosegeneratingtheirownelectricity.Unusedelectricityissoldtoa supplier, currently at 4.5p per unit.

• In2010theinstalledcapacityofsolarpanelswas2MWbutbytheendof2013thishadincreased to over 100MW. This rapid increase is expected to continue.



• Lowmaintenancecosts


• Lowenvironmentalimpactif they are being installed on existing buildings

• Up-frontinstallationcosts

• Solarpanelscannotgenerateelectricityatalltimesofpeak demand, night time being a particular problem. Batteries can be used to store electricity made during the day but it might not always be enough

• Largescaleprojectssuchassolarfarmswillusealargearea and could have a significant impact on the local environment

• Rapidexpansionofcapacityfromsolarpanelswillimpact on the National Grid. If the UK-wide capacity reaches 10GW, then significant work will need to be carried out to infrastructure

• Difficulttostoreexcesselectricityforlonger term use

SP Energy Netw

orks

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Horizontal axis wind turbine

Wind Power• Therearemorethan80windfarms(asitewithmorethan1windturbine)acrossScotland,

either onshore or offshore with a total capacity of 2GW.

• Theamountofelectricityactuallygeneratedfromthesefarmsdependsontheweather.

• Individualwindturbinescanalsobefoundprovidingpowertoindividualhomes,businessesand communities.

Wind Turbines

History

• Windturbineshavealonghistoryandhavebeenusedforcenturies.Builtin1880,theDickie wind pump (seen below at the National Museum of Rural Life in East Kilbride) was developedbyWilliamDickie,anAgriculturalEngineer,toprovidewaterfordomesticandagricultural use.

• Thiswasquicklyfollowedbytheworld’sfirstelectricitygeneratingwindturbine.BuiltinMarykirk, Scotland in 1887 by electrical engineer James Blyth.

• Itwasn’tuntilthemid-20thcenturythatwindturbinesbegantobeusedacrosstheUK.Prior to this they were considered too expensive.

Design

• Engineersdesignwindturbinessothattheywork best for average conditions on the site.

• Theyalwayshavetotakeintoaccounttheworst possible weather conditions and plan for how the turbine is affected in extremely high winds.

• Whenchoosingasiteforawindfarmorturbine, it is preferable that the area has medium to high wind speeds.

• Theturbinebladesspinwhenthewindisabove a certain speed. This then drives an electrical generator.

• Thematerialstheyaremadefromincludesteel and aluminium but will depend on the design.

Dickie wind pump

Types of Turbine

There are 2 types of turbines based on their axis of rotation:

1. Horizontal axis

• Rotorbladesandageneratorareplacedatthetopofatower(thiscanrangeinsize up to 90-100m). They must be pointed into the wind and are controlled by computer.

• Sizeisimportantbecausewindspeedincreaseswithheight.

• Todrivethegenerator,thespeedoftherotatingbladesiscontrolledbyagearbox.

• Thebladesmustbefarawayfromthetowersothattheycannotdamageit.

• Thespeedatthetipoftherotorbladescanreachover300km/h.

• Brakesarebuiltintotheturbine,toprotectitinhighwinds.

The largest offshore turbine in the world was installed in Fife in October 2013, reaching 196m to its tip and sitting 50m out into the Firth of Forth. This will produce 7MW, enough for nearly 5,000 homes. The height of this turbine is greater than the nearby Forth road bridge.

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Vertical axis wind turbine

2. Vertical axis

• Thegeneratorandgearsareplacedatthebottomoftheturbine.

• Duetoitsdesignitdoesn’thavetofacethewind.

• Thistypeismostsuitedtosittingonabuildingwherethewinddirectionwillfrequentlychange, rather than form part of a wind farm.

Turbulence

We often see wind turbines sitting by themselves at a business such as a farm or factory and planning for how these operate is slightly more straightforward than for a wind farm. The reason being is that as soon as you have more than one wind turbine, you increase the turbulence in the air. Wind farms with a large number of turbines will be spaced apart to minimise the effect of turbulence.

Turbulence is an ongoing field of study and there are disagreements as to how far apart wind turbines should be placed, with some arguing 6-10 times the length of the blades and others saying they should be placed much closer together.



• Lowmaintenancecosts


• Windspeedisvariable

• Peakproductionnotalwaysattimeofpeakdemand

• Expensivetoinstall.Offshorewindfarmsare20%more expensive than onshore

• Largeturbinesandwindfarmscanhaveanegativeeffect appearance of an area

• Turbinesgeneratenoise.Amountneedstobeconsidered when choosing a site

• Theinstallationofawindfarmcanimpactthelocalenvironment

SSE Power D

istribution

1918

Wave PowerThere are two different aspects of the sea that we can try to harness for the purposes of generating electricity: tides and waves. Both are in the very early stages of development. In this instance we are considering waves and not tides.

• Onekeydifferencebetweentidesandwavesisthatwehaveaveryclearunderstandingof the behaviour of tides in the long term.

• Wavesareproducedwhenwindblowsoverthesurfaceoftheseaandcanbepredictedseveral days in advance.

• Thelargestwavesaregeneratedwhenthewindhasblownoverlongdistancesacross an ocean.

• SuitablesitesaroundtheUKforwavepowercanbefoundaroundoffthenorthwestcoastofScotland,NorthernIreland,southWalesandCornwall.AtthesepointsthewindhasbeenpassingovergreatdistancesacrosstheAtlanticOcean.

• Wavesreduceinsizeastheyapproachthecoastduetofriction,asthedepthdecreases,so the best sites are found out at sea.

Wave Characteristics

Waves produced in the sea are transverse waves. This means that the vibrations are at right angles to the direction of travel.

The speed of a wave can be found based on the frequency and wavelength:

Wave speed (metres per second)=Frequency (Hertz)×Wavelength (metre)

The following can also be considered for finding the speed of a wave:

Speed (metres per second) = Distance (metres)

Time (seconds)

Amplitude

Wavelength, y

Wave Power Technology

Therearemanydifferenttypesofwavetechnologyunderdevelopment.Asyetwavepowerisn’tused commercially, but this is the goal being worked towards world-wide.

History

• Wavepowerdoesnothaveaslongahistoryaswindorhydrobuttherearemanyuniversities and companies in Scotland researching methods of electricity generation.

• Spurredonbyhighoilpricesandproblemswithsupplyinthe1970s,fundingwasmadeavailable to research ways of generating electricity using the power of the waves.

• Salter’sDuck,designedbyagroupattheUniversityofEdinburghledbyProfessorStephenSalter, uses the motion of the waves to drive gyroscopes inside the duck, where an electrical generator then uses the rotation from the gyroscopes to produce electricity.

• AmodelofSalter’sDuckcanbeviewedintheNationalMuseumofScotland.

• Unfortunatelyduetovariousfactors,includingadropinoilpricesinthe1980sandacutinfunding for renewable research, it was never developed beyond a prototype.

Based across various sites across the Orkney Islands, the European Marine Energy Centre (EMEC) is a place where new technologies across tidal and wave power can be tested. Once tested, the technologies can be scaled up and installed at other sites. This is a world-leading site, more wave and tidal technologies are tested in Orkney than the rest of the world combined.

Pelamis Sea Snake

Pelamis W

ave Power

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Examples of Technology

• SeverallargewavefarmsitesareintheplanningstagesaroundScotland.Forexample,the Pelamis Sea Snake is being tested at EMEC with a plan that over 50 machines be established in a nearby wave farm with a potential capacity of 50MW.

• ThePelamisSeaSnakeismadeupofseveraltubesthatareconnectedbutmoveupanddown independently in the waves. This motion drives hydraulics inside the units which in turn produces electricity from a generator. The machine is then linked to shore via a cable.

• Differenttechnologiesneedavarietyofseastatesanddepths,sothiswillhaveanimpacton how close to shore they will be situated.

• Thetechnologiescanbegroupedintooffshore,near-shoreoron-shore.

• Themachinesusedarefoundonthesurfaceofthesea,submergedoracombinationofthe two.

• Themostcommonapproachison-surface:thePelamisSeaSnakeandSalter’sDuckareexamples of on-surface generation.




• Wavesarebuiltupbywindand travel long distances. Wave power can therefore compliment wind power as the peak waves will come a few days after peak winds

• Wavepowersitesareoftenoutatseaandthereforefar away from electricity consumers. Losses will be experienced in moving the generated electricity over any distance

• Wavesizeisvariableandnotconstant

• Peakoutputdoesnotnecessarilymeetpeakdemandfrom consumers

• Asthetechnologiesarestillearlyintheirdevelopment,there is more to learn about their impact on the environment, for example fishing, and how they perform longer term in challenging conditions

Compared with other types of renewable electricity generation, wave power uses many different technologies. This can have an impact on the advantages and disadvantages. For example, an on-shore technology is easier to access for maintenance than an off-shore one.

Further SourcesIf you would like to investigate more about these areas, you may find the following sites useful for background information.

Aquaretmarinepower:www.aquaret.com

The Crown Estate: www.thecrownestate.co.uk/estates-map/map

DanishWindIndustryAssociation: www.windpower.org/en/knowledge/wind_with_miller.html

Energy statistics for Scotland: www.scotland.gov.uk/Topics/Statistics/Browse/Business/Energy

European Marine Energy Centre: www.emec.org.uk

Met Office Weather Data: www.metoffice.gov.uk/forms/education_weather_data_order.html

Renewable UK: www.renewableuk.com

Whitelee Wind Farm (largest in Europe): www.whiteleewindfarm.co.uk/visitor_centre/opening_hours

The following sites have further activities and resources on renewable energy suitable for school pupils:

National STEM Centre e-Library: www.nationalstemcentre.org.uk/elibrary

The Solar Spark: www.thesolarspark.co.uk

SSERC: www.sserc.org.uk

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Pupil Challenges

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Team name:Hydro Power ChallengeYourchallengeistobuildamodelhydroelectricpowerstation.

Youwillneedto:

(i) Find out the acceleration of an object due to gravity

(ii) Calculate the gravitational potential energy of your power station

(iii) Design and build a water turbine.

(iv) Record the voltage generated by the turbine and identify any sources of loss.

Yourteamshouldmakearecordofyouractivitythroughashortverbalreport (2 minutes max).

Organising the Team

1. Choose a Project Manager for the team

2. Decide on a team name

3. Divide the team into 2 sub-groups

a. Sub group 1: Calculate the acceleration due to gravity and the gravitational potential energy of the power station

b. Sub group 2: Design and build a water turbine.

Equipment

Sub-group 1:

1. To find the acceleration due to gravity you will need: an object to drop (e.g. a water balloon), timer, metre ruler or measuring tape and a calculator.

2. To calculate the gravitational potential energy of the power station you will need a metre ruler or measuring tape and a calculator.

Sub-group 2:

To design and build a water turbine you will need: a plastic bottle, cut into three pieces (top, middle and bottom separated), electrical tape, scissors, connection to electric motor, multi-meter, wires and motor.

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Team name: Team name:Hydro Power Challenge Hydro Power Challenge

Sub-group 1Calculate the acceleration due to gravity and the gravitational potential energy of the power station.

(i) Acceleration due to gravity

In order to make calculations about the hydroelectric power station you need to know the value of the acceleration due to gravity.

To find the acceleration, you can drop an object several times and record the time it takes to fall. Choosealocationwhereyoucansafelydropanobjectfromaheight(atleast5m).Youneed2people: one to drop the object and the other to record the time taken for the drop.

In order to calculate acceleration due to gravity you should use the following equation:

Acceleration due to gravity = 2 × distance (m)

time2 (s2)

Youwillneedtorecordthetimeittakestheobjecttodropandfindthedistancetheobjectfalls.Itisimportant that your value for the acceleration due to gravity is measured in metres per second per second (ms-2).

Repeat the drop at least 5 times. Once you have a number of different times you can then find an average value.

(ii) Gravitational Potential Energy

The table below outlines the 3 main components to the water flow in a hydroelectric power station.

The table shows what you can use in the model for each component.

Component Model can use

1. Ahighreservoir Container (with tap) of water

2. Achannelfortheflowingwater Tubing

3. Alowreservoirforthewatertoflowinto Asinkorbasin

Useful Information

Height is an important factor when considering the design of a power station. By having water at a height, there is stored energy. It has gravitational potential energy:

Ep = mgh

Where m is the mass of the water, g is the gravitational field strength and h is the height.

When the water falls, the potential energy is transferred to kinetic energy, which in turn becomes mechanical energy to turn the turbine and drive the electrical generator.

High-level reservoir

Low-level loch

Height

Water flow

Turbines andelectrical generators

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Team name: Team name:Hydro Power Challenge Hydro Power ChallengeCalculating the Gravitational Potential Energy and Power for your Power Station

There are still two unknowns in the equation for gravitation potential energy that you have to find: the height of the power station and mass of water. For g you should use the result from part (i) Accelerationduetogravity.

• Tofindtheheight,h:measuretheheightofyourcontainerabovethesinkorbasin.

• Tofindthemass,m:youcandothisifyouknowthevolumeofwaterinthecontainer, as 1 litre = 1 kilogram.

Youcannowcompletethecalculationfortheenergy:

Energy =

Will all of this energy be used to generate electricity? Explain your answer.

It is useful to know the power of your hydroelectric model. Power can be found using:

P = E t

If you ran your power station for one hour, what would the power be?

Remember to convert one hour into seconds.

Power =

An impulse turbine

Sub-group 2: Design and Build a TurbineThere are two types of turbines used in hydroelectric power stations: reaction and impulse.

• Areactionturbineisfullysurroundedbywater.

• Animpulseturbineusesajettoturntheblades.

Reaction turbine Impulse turbine

Yourchallengeistobuildanimpulseturbine.Kineticenergyfromthewaterwillbecomethemechanical energy of your turbine. The turbine then drives the generator to produce electricity.

Using the materials supplied, design and construct blades that will turn efficiently when the water stream hits.

1. Start by sketching your design.

2. Build and test.

Remember to test your design and make changes if necessary. Testing is an important part of the design process.

3. Record the voltage produced

Practice supplying the turbine with water. Once you are happy that it is turning smoothly, connect the turbine to the electric generator. Supply water to the turbine and measure the voltage and current produced by your hydroelectric power station.

Youshouldrecordthemaximumvoltageshownonthemulti-meterwhenyourturbineisrunningin the water.

Voltage =

A Reaction turbine

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Team name:Solar Power ChallengeYourchallengeistodecidewhichof3potentialsitesinScotlandwouldbethebestplacetobuild a solar farm.

Youwillneedto:

(i) Research the three potential sites, deciding on their advantages and disadvantages.

(ii) Investigate the operation of a single solar panel.

(iii) Begin construction of a model of the solar farm.

Yourteamshouldpresentyourdecisioninashortverbalreport(2minutesmax).

Organising the Team



3. Divide the team into 2 sub-groups

a. Sub-group 1: Engineering unit to investigate the output of a solar panel in different seasons and build a model of the farm.

b. Sub-group 2: Business unit responsible for researching the sites and presenting the team decision.

Equipment

Sub-group 1:

• Solarpanel,multi-meter,wires,metrerulerormeasuringtape,protractor,calculator,lamp,1 Ω resistor, string.

• Buildingmaterials,suchasLEGO.

Sub-group 2:

• Calculator,siteinformationsheets:oneeachforMotherwell,Stirling,Edinburgh.

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Team name: Team name:Solar Power ChallengeSolar Power Challenge

Solar panel

0.2 m

h

Summer

Autumn

Spring

Winter

Sub-group 1: Engineering UnitPart 1. Solar Panel Investigation

Based on measurements of the voltage output from the solar panel, your job is to calculate the power ofthesolarpanelstobeusedinthesolarfarm.Youhaveasolarpaneltotestandalamptorepresentthe sun. Complete the following steps:

1. Youwillbesuppliedwithasolarpanelconnectedtoa1Ωresistor. Attachthemulti-metertothecircuitsothatyoucanrecordthevoltage.

2. The lamp represents the Sun. Plug the lamp in and turn it on.

3. The height of the Sun in the sky is different across the seasons.

4. To begin with you will measure the output of the solar panel in summer. Mark 20 cm on a length of string and fix one end to a side of the solar panel, half way up. This will ensure the lamp is held the correct distance from the solar panel.

5. Usingarulerasaguide,holdthelamp20cmabovethedesk.Atthe same time use the marked piece of string to hold the lamp the correct distance from the solar panel, with the lamp pointed towards the panel.

6. Anotherpersonshouldnowtiltthesolarpanelawayfromthelamp,startingat90degrees.Findthe angle of the solar panel that gives you the maximum voltage (shown on the multi-meter).

7. Record the angle of the panel (find the angle by using your protractor) that gives the maximum voltage for summer and record it in the table below:

Summer

Panel angle

Voltage, V

8. The table below tells you how the output of the solar panel changes across the seasons. For example, the output in winter is much less than in summer. Based on the figures in the table, find the output of the solar panel in winter, spring and autumn.

Season Winter Spring Summer Autumn

Output percentage compared with summer

20% 80% 100% 80%

Output voltage

9. Youcanfindthecurrent,I,basedonthevoltage,V,andtheknowledgethattheresistance,R, of the circuit is 1 Ω. Complete the table below.

V = IR I = V—R

Winter Spring Summer Autumn

Voltage, V

Current, I

10. Find the power output, P, of the solar panel for each season. Use voltage, V, and current, I, from the table above and complete the table below.

P = IV


Power, P

11. These values have been found using a solar panel with an area of 0.1m2. The total solar panel area to be installed is 4000 m2. What factor do you have to multiply your power values by to find the power for the whole site? _________________ Using this factor complete the table below:


Power, W

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Team name: Team name:Solar Power ChallengeSolar Power Challenge

Part 2. Building a model

Before you can build a model of your solar farm, you need to decide which of the three sites you willbuilditat.Alongwithsub-group1(theBusinessunit)yourteamshouldchooseasite.

Chosen site =

Yoursub-groupcannowbeginconstructionofthesolarfarmandwillbesuppliedwiththenecessary equipment.

• IfyouhavechosenMotherwellyoursolarpanelswillneedtobeatanangleof35degrees.

• IfyouhavechosenStirlingasthesiteofyoursolarfarm,yourangleneedstobe40degrees.

• IfyouhaveselectedEdinburgh,youneedtoconstructabuildingthatisatleast5cmhighand 9 cm wide. In this case your solar panel must be at 45 degrees, as the buildings for your panels already exist.

Repeat the measurements you did in Part 1 using your model, as the angle of the solar panel may now be different. When making the measurement for summer, measure the height of the lamp from the level of the solar panel and not from the level of the desk.

Summer

Voltage, V

Current, I

Power, P

Winter (20% of summer output)

Spring (80% of summer output)

Autumn (80% of summer output)

Voltage, V

Current, I

Power, P

Total power =

Remember to use your scale up factor from step 11 so that your final power values cover the total area of the site.

Once you have completed the last table, give the results to sub-group 2 (the Business unit).

Sub-group 2: Business UnitPart 1. Researching the Sites

Yoursub-groupwillneedtobriefsub-group1(theEngineeringunit)ontheadvantagesanddisadvantages of the different sites. It is important to find the best time to have this discussion with sub-group 1.

Use the site information sheets provided for each location. Summarise the advantages and disadvantages for each site:

Site 1: Motherwell

Advantages Disadvantages

Site 2: Stirling


Site 3: Edinburgh


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Team name: Team name:Wind Power ChallengeSolar Power ChallengePart 2. Site capacity

We now want to record the energy capacity of your chosen site. The number of hours of sunshine will affect the maximum capacity of the solar farm. Each site has the same number of daylight hours available as they are not far apart. Complete the following table:


Sunrise 08:45 06:17 04:31 07:00

Sunset 15:45 18:31 22:05 19:20

Daylight in 1 day

Number of days 90 92 93 90

Daylight hours in the season

Total daylight for 1 year (in seconds):

Sub-group 1 (the Engineering unit) has calculated the Power of the site, P based on their measurements.Youneedthesevaluesfromthemalongwiththeoutputofyourdaylightcalculationin order to find the capacity of the site. Using the following equation for Energy, find the maximum capacity for your chosen site:

E = P × t

Winter Spring Summer Autumn Total

Energy, E

Part 3. Presentation of Results

AstheBusinessDevelopmentUnit,younowhavetoputacasetogethertopresentyourfindings.Youshould include a summary of the chosen site’s advantages and disadvantages, the maximum energy capacity of the site, the total cost and why you chose it.

YourchallengeistodecidewhethertheNationalMuseumofRuralLifeisasuitablelocationforawindfarm.Youneedtoinvestigate:

(i) how wind turbines work

(ii) the local environment and weather conditions to decide whether the site is suitable or unsuitable for a wind farm.


General Information

• Theproposedwindfarmhasatotalof6windturbines,givingatotalpotentialpowerof3MW. This would supply around 2,000 homes.

• Intotal,itshouldtakearound1yearforconstructiontobecompleteandconnectiontotheNational Grid made.

• Theexistingsiteisamuseumandworkingfarmwithlivestock

• Inadditiontotheconstructionworkofthewindfarm,furtherworkisneededtoconnectthewind farm to the National Grid by building a substation.

• Whiteleewindfarm(theUK’slargestonshorewindfarm)withover200turbinesiswithin10 miles of the site and can be clearly seen.

Organising the team

1. Choose a Project Manager for the team.

2. Decide on a team name.

3. Divide the team into 2 sub-groups and choose a leader for each:

a. Sub-group 1: investigate wind turbines

b. Sub-group 2: investigate the local area

Equipment

Sub-group 1: Wind turbine kit, multi-meter, wires, electric fan.

Sub-group 2: Rural life information sheets, calculator.

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Team name: Team name:Wind Power ChallengeWind Power Challenge

Project ManagerYour role:

1. Make sure all team members read the general information notes.

2. Before the team divides into 2 sub-groups discuss this question with the whole team:

• HowdoyoudecidewhetherornottheNationalMuseumofRuralLifeissuitableforawind farm?

• Listthedifferentkindsofinformationyouwouldlikeforthesite.Foreachdifferentkind,explain why.

Hand in your request to the activity leader. The activity leader will then give you the wind turbinekitandRuralLifeInformationsheets.Yourteamshoulddivideintosub-groupstofinish the challenge.

3. Check that the sub-groups understand their task

4. Agreehowlongeachgrouphasfortheirtaskandkeeptrackoftheirprogress

5. Bring groups together for reporting back and decision making

6. What is the team’s final recommendation for the site and why?

Horizontal axis wind turbine

Sub-group 1: Investigating wind turbines1. Set up your wind turbine kit and connect the generator to the voltmeter.

2. Try different numbers of blades on the turbine.

3. Each time you have a new set up, turn the fan onto the highest setting and record the output on the voltmeter.

4. If you vary the angle of the blades can you increase the output?

5. Using trial and error, find the number of blades that gives the maximum output on the voltmeter.

6. Record your results in the table below:

Number of blades Maximum voltage

Technical Information for turbines to be installed at Rural Life

Turbine Technical Specification:

• Height(tothetopoftheblade):45m

• Groundarearequired:5m2

• Minimumwindspeed:4ms-1

• Maximumwindspeed(survivalspeed):60ms-1

• Optimumwindspeedrange:7.5ms-1

• Efficiency:36%

• Maximumpoweroutput:500kW

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Team name: Team name:Wave Power ChallengeWind Power Challenge

Sub-group 2: Researching the local conditionsYouwillhaveaccesstomapsandphotographsofthesiteandtherearethreeinformationsheetsonRural Life, they cover:

• ThePhysicalEnvironment

• AnimalLife

• WeatherConditions

The weather conditions information is incomplete, you will need to take wind readings and find the average wind speed for the site.

From this information, summarise the advantages and disadvantages of putting a wind farm at Rural Life. This will be shared with Sub-Group 1. They will be particularly interested in the weather conditions, but you should also consider the wider impact of putting the wind farm on this site.

Averagewindspeed =

Maximum wind speed =

Minimum wind speed =


Youhavebeengiven£5,000,000toinvestinthedevelopmentofatypeofwavepowertechnology.Yourchallengeistochoosebetweentwodifferentwavepowertechnologies.Tomake a decision you will need to take measurements of frequency, amplitude and wavelength ofwaves.Youcanthentesteachwavepowermodeltolearnmoreabouthowitworks.

Youwillneedto:

(i) Research wave characteristics, such as frequency, amplitude and wavelength.

(ii) Investigate how the two kinds of wave technology works and find out more about the company developing it.


Organising the Team



3. Divide the team into 2 sub-groups and choose a group leader for each group. Each sub-group is responsible for investigating a different type of wave power technology in part 2.

Equipment

Part1:Awavetankwithwavegenerator,ruler,calculator.

Part 2:

• Sub-group1:Awavetankwithwavegenerator,amodelofawavepowertechnology.

• Sub-group2:Awavetankwithwavegenerator,amodelofadifferentwavepowertechnology.

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Team name: Team name:

Amplitude

Wavelength, y

Wave Power ChallengeWave Power Challenge

Part 1. Researching wave characteristics• Amplitude:thisistheheightofthewaveasmeasuredfromitscalmorundisturbedstate

• Wavelength:thisisthedistancebetweentwopoints,eachonthesamepointontwodifferent waves

• Frequency:thisisthenumberofwavesthatpassacertainpointinasecond,measured in Hertz, Hz.

Using the wave tank measure the amplitude and wavelength for a wave.

The waves used for generating electricity have been built up across vast distances. However, the speed of a wave is frequency times wavelength.

Using the wave tank, find the frequency of the waves in the tank. Set the dial first at 12 o’clock andthen5o’clock.Youcanfindthefrequencybycountingthenumberofwavesthatpassapoint in a set time, then divide by the number of seconds.

Dial position Frequency (Hz)

12 o’clock

5 o’clock

Part 2. Investigating wave power technologiesBackground Research

Split into your 2 sub-groups. Each group should investigate one of the wave technologies and associatedcompany.YouwillfindinformationaboutthecompaniesandtechnologiesintheCompany Information sheets. Find out the following and record your findings in the Company 1 and 2 answer sheets:

1. Market Potential

The number of potential locations on the Scottish coast which meet the wave requirements for each technology are unknown. Using the chart of the Scottish coast and the location information sheet identify the number of potential sites.

a. Company 1: Refer to the technical specification for this company in the Company 1 information sheet. Use this information to find the potential sites.

b. Company 2: This company has not supplied technical information. Based on where their technology is either already being used (position 4 on the chart) or where a site is under construction (position 13 on the chart), make an estimate of the technical requirements for the technology. Identify any other potential sites.

2. Profit

a. Using the financial information in the company information sheets, calculate the investor share of the profit after 3 years.

b. Willtheyrecovertheir£5,000,000investmentafter3years?

3. National Grid

Moving electricity to where it is needed by homes and businesses is very important. The National Grid is used to move electricity around the country. It can be expensive to install new links to the grid. Using the map of National Grid connections, is there a connection available at

the potential locations you have identified?

Testing

Both companies have fully tested a scale model prototype, however they have not shared the results ofthetests.Youcantesteachmodelinawavetankandobservethebehaviourofthemodelindifferent wave heights.

Answerthefollowingquestions.

• Doesthedevicematchthefrequencyofthewaves?Ifso,whatfrequency?

• Howdoesthemodelbehaveinsmallwaves?

• Howdoesthemodelbehaveinlargewaves?

Summarise the advantages and disadvantages of each technology.

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Team name:Wave Power Challenge

Part 3. Investment Decision

Each sub-group should now share the information they have found with the rest of the team.

Based on what you have learned, which wave power technology do you want to invest in and why?

Get Energised! - National Museums Scotland · 2016. 1. 6. · 2. Run-of-river (as seen in the...

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