Unit 5. Energy5.1 Energy 1.1Units 1.2 Forms and Sources5.2 Electric energy 2.1 Generation 2.2 Main Power Stations 2.3 Distribution5.3 Consume
5.1.1 Energy. UnitsEnergy is the capacity of an object to do a work.And work is the force applied along a distance
5.1.1 Energy. UnitsIn physics we define mechanical work asthe amount of energy transferred by aforce acting through a distance d= distance between A and B W= F•d F= Force applied to move the object F d
5.1.1 Energy. UnitsTherefore, in this example, the energythat black cartoon has, the express thework that can apply to this box,
5.1.1 Energy. Units UnitsThere are several units of energy that areused in special areas, the most popular arethe j, cal and kwh. Joule calorie kwh
5.1.1 Energy. UnitsJoule (J) is the InternationalSystem’s unit for work, and is usuallyexpressed in Kj. 1 meter 1kj is the energy need to raise 100kg 1 meter high
5.1.1 Energy. UnitsCalorie (cal) This unit is usually used toexpress energy that involves calorifictransference. When energy is used in thealimentary industry, it’s usually express inKcal.In the USA, they write Cal instead ofKcal… In order to heat 1 L of water from 20 to 21 ºC we need 1kcal
5.1.1 Energy. UnitsA human being needs around 2000 kcalper day of energy to do all the work thatit needs.
5.1.1 Energy. UnitsWhen you drink a Coke you are absorbing139 Kcal of energy that is stored in the39gr of sugar dissolved in the liquid. 139 Kcal 420Kcal 840Kcal
5.1.1 1º ExerciseInvestigate the energy that these foodshave per 100 gr:Yogurt Big MacBread AppleBiscuits Orange FantaCereals OilChips Butter Solution
5.1.1 Energy. UnitsKiloWatt/hour(kwh) It’s the unit used tomeasure the electric consumption of anelectric installation. When we use a hairdrier of 1000 W for 1h, we have consumed 1 kwh
5.1.1 2º Exercise Conversion units Solution 1Kwh= 1000Wh 1 W= 1 j/s 1calorie= 4,18 joules2º Exercise:• alculate the energy of a Coke in joules. C• alculate the energy measured in kwh that Cwe absorb in 2h when we drink 2 Cokes?• f we use a 100W lamp, and we use Cokes to Iprovide energy, how many Cokes do we needper second?
5.1.2 Forms and Sources So Energy is the capacity of an object to do a work, and it can be stored in different forms of enery: Electric energy Mechanical Nuclear energyLight energy energy Electrical energy Calorific energy Chemical energy
5.1.2 Forms and Sources The law of conservation of energy expresses that can neither be created nor destroyed, it can only be transformed from one state to another Nuclear energy Electric energy Mechanical energyLight energy Electrical Calorific energy energy Chemical energy
5.1.2 Forms and SourcesIn order to obtain energy we have to use the different energy sources present in Earth: oil, coal, wind, uranium, etc.
5.1.2 Forms and SourcesWe can classify the energy sources according to its:Origin: Renewable or Non RenewableHistorical use: traditional or alternativeTransformation: Primary or secondary
5.1.2 Forms and Sources3º Exercise:a) xplain the difference between E the concepts of source and form of energy.b) efine the six groups of energy D sources, and give four examples of each. solution
5.1.2 Forms and SourcesOrigin:a) enewable : These sources are R Inexhaustible, therefore we can use them continuously. For example: Wind, Waves, etc…
5.1.2 Forms and SourcesOrigin: .a) b) on Renewable : These sources are N exhaustible, therefore we consume the source when we use it. For example: oil, Uranium
5.1.2 Forms and SourcesHistorical use:a) raditional: these sources have been T used for at least 30 years, and they provide more than the 90% global energy. They are:Hydraulic, Coal, Oil, Gas, Uranium
5.1.2 Forms and SourcesHistorical use:a) Traditionalb) lternative: these sources can provide A energy but they can’t displace the alternative energy because they are cheaper or easier to obtain. For exampleSolar Wind bio-mass Wave Geothermal
5.1.2 Forms and Sources Transformation:a) rimary: These sources are obtained P directly from the environment and they can be used directly without any transformation.For example:Hydraulic, Coal, Oil, Gas, Solar Wind bio-mass Wave Geothermal
5.1.2 Forms and Sources Transformation:a) Primary:b) econdary: These sources are obtained S after the transformation of a primary source. We use them because they are cleaner or easier to useFor example:Electricity, Oil derivatives (Gasoline, Diesel, etc), Town Gas
5.1.2 exercise 5Forms and Sources5º Exercise: Make a list of 20 objects indicating the form of energy used and the energy obtained .For example: TV-Electricity Sol Object Energy Form Energy obtained TV Electricity Light . . . . . . . . .
Electricity production.Why do we like Electricity so much?
5.2.1 Electric energy. GenerationElectricity is the principal source of energy in the developed homes and in industries because it’s the cleanest and most versatile energy.
5.2.1 Exercise. Electric energy. Production1º Exercise:Compare the use of electricity at home with the use of coal, oil, gas, solar, wind, geothermal, uranium.2º Exercise:What do we mean when we say that the electricity is clean? Solution
5.2.1 Electric energy. GenerationAs we know, if we want to create an artificial electric current, we only need: A closed circuit An artificial magnetic field A mechanical energy to move the circuit inside the field.
5.2.1 Electric energy. GenerationWhen we have all elements together, we find that we create an alternate electric current due to the movement of the spiral.
5.2.2 Electric energy. Power Stations The only difference between power stations is how they get the energy to move the turbine that moves the circuit inside the generator turbine Generator
5.2.2 Electric energy. Power Stations One big group of use different sources to HEAT water and create steam to move the turbine steam turbine
5.2.1 Electric energy. Generation Other small group use the primary source to move the turbine, using water or wind
5.2.1 Electric energy. GenerationIn conclusion we will always find these elements in a Power Station: Electric TransportPrimary Mechanical ElectricEnergy Energy generation Electric Transformation Transformer Turbine Generator
5.2.1 Electric energy. GenerationAnd this is the summary of the production in a block diagram Primary Mechanical Electric Electric Energy Energy generation Transformation Water or Air Turbine Generator Transformer Steam from a combustion, nuclear Electricreaction, solar Transportor geothermal
5.2.2 Electric energy. Power Stations Turbine Mechanical Water, Energy Wind Generator Steam ElectricityAll Power stations will have this elements, now we will Transformer see how they move the High Volt turbines Pylon
5.2.2 Electric energy. Power Stations Steam Power Station Diagram Turbine Mechanical Steam Energy Steam Boiler Cold Generator Water Electricity Heat Cooling TransformerWe use the energy source to High Volt create steam pressure to move the turbine Pylon
5.2.2 Electric energy. Power StationsWater Turbine Mechanical EnergyWind Generator ElectricityWe use the primary Transformer Energy like wind or water High Volt pressure to move the turbine Pylon
5.2.2 Electric energy. Power StationsCoal power Station Steam pressure
5.2.2 Electric energy. Power Stations Coal power Station Diagram Turbine Mechanical Steam Energy Steam Boiler Cold Generator Water Electricity Heat Cooling Coal TransformerMine Furnace High Volt Pylons
5.2.2 Electric energy. Power Stations9º Exercise.Draw the diagram of all Power Stations as we have seen in the Coal Station Diagram
5.2.2 Electric energy. Power StationsCoal power StationAdvantagesInexpensive compared to other energy sourcesCoal is present in most of the countries, so they don’t have to buy it abroadBy-product of burning, ash, can be used for concrete and roadwaysDisadvantagesLimited supply, non-renewable resource. 100 yearsThe Carbon dioxide generated increase the effect of the global warming.Generated smoke can cause health conditions such as emphysemaSulphur dioxide and nitrogen emissions can bind to water creating acid rainCoal mining mars the landscape
5.2.2 Electric energy. Power StationsNuclear power station Diagram Infografía
5.2.2 Electric energy. Power StationsNuclear power stationAdvantagesWorldwide nuclear energy avoids on average the emission of more than two billion metric tones of carbon dioxide per year, decreasing the effect of the global warming.Although nuclear power reactors are expensive to build, they are relatively cheap to operate.It is possible to generate a high amount of electrical energy in one single plant.DisadvantagesThe waste from nuclear energy is extremely dangerous and it has to be carefully looked after for several thousand years .Despite a generally high security standard, accidents can still happen.Nuclear power plants as well as nuclear waste could be preferred targets for terrorist attacks.Is a non renewable source. 50 years
5.2.2 Electric energy. Power Stations DiagramHydro Power StationPrimary Energy
5.2.2 Electric energy. Power StationsHydro Power StationAdvantagesWhen the electricity is generated, no greenhouse gases are made.Water is a renewable energy source and free.We create huge potable water deposits.DisadvantagesThe dam is expensive to build and the nearby area has to be floodedIn drought season we may not have enough water to turn the turbines.
5.2.2 Electric energy. Power Stations Solar Power Tower Plant DiagramSteam pressure
5.2.2 Electric energy. Power Stations DiagramSolar photovoltaic Plant
5.2.2 Electric energy. Power StationsSolar EnergyAdvantagesInexhaustible fuel sourceNo greenhouse gasses emitedVersatile since it is used for powering items as diverse as solar cars and satellitesDisadvantagesIt does not work at night.Very diffuse source means low energy production.Only areas of the world with lots of sunlight are suitable for solar power generationThey need great lands creating high temperatures below the panels
5.2.2 Electric energy. Power Stations Diagram Wind PlantPrimary Energy
5.2.2 Electric energy. Power Stations Wind Plant Advantages It is available over a greater area than occurs with fossil fuels. There is no air pollution after manufacture. Modern wind energy converter systems can be set up for individual houses. Wind energy produces more energy per area of land than other energy sources. Disadvantages Modern wind energy systems are expensive, although the source is free. They can be rather ugly or the noise of the rotor could be annoying if the installation is located close to homes or workplaces. The wind does not blow all the time. Potential TV interference caused by rotor.
5.2.2 Electric energy. PowerStations DiagramTide EnergyPrimary Energy
5.2.2 Electric energy. PowerStationsTide EnergyAdvantagesTides are free once the power station has been built and will not run out.No greenhouse gases are produce.We know exactly when the tides happen so we know when electricity will be made.DisdvantagesDams may not be good for plants and animals that live nearby.The tides only happen twice a day, so can only produce electricity for that time.
5.2.2 Electric energy. PowerStationsWave EnergyPrimary Energy
5.2.2 Electric energy. Power StationsWave EnergyAdvantagesWaves are free and will not run out so the cost is in building the power station.Wave power does not produce greenhouse gases.There are very few safety risks with wave power generation.DisdvantagesWaves can be big or small so you may not always be able to generate electricity.You need to find a way of transporting the electricity from the sea onto the land.Not many people have tried to generate electricity this way yet so the equipment is expen-sive.
5.2.2 Electric energy. Power StationsBiomass Diagram. Natural Dry Wet Energetic biomass Biomass Biomass Crops Waste Human or High from animal Energy industrial disposal Plants process AreSteam pressure cultivated
5.2.2 Electric energy. Power StationsBiomassAdvantagesThe fuel is cheap and can use things that we might otherwise throw away.We can find waste everywhere and should not run out.DisadvantagesWhen the fuel is burned greenhouse gases are made which pollute the environment.Sometimes people grow biomass crops where we could grow food.We may not have enough space to grow enough biomass fuel.
5.2.2 Electric energy. Power Stations Diagram Geothermal EnergySteam pressure
5.2.2 Electric energy. Power StationsGeothermal EnergyAdvantagesGeothermal energy does not produce greenhouse gasesThe energy source is free and will not run outDisadvantagesThere are not many places where we can build geothermal power stationsHarmful gases and minerals may occasionally come up from the ground below. These can bedifficult to control.
5.2.2 Electric energy. Power StationsFusion Energy the Future Energy Steam pressure
5.2.2 Electric energy. Power StationsSource Renowable/ Type of Advantages Disavantag Non reno. central esWind ThermicalWater Radioactive waste Tide
5.2.3 Electric energy. DistributionOnce we create electricity we have to transport it to the final users. Nowadays we use these elements: Final User Transformer Transformer Pylons
5.2.3 Electric energy. DistributionWhy do we need a transformer???
5.2.3 Electric energy. DistributionAll conductors have resistance, and its opposition to the intensity creates HEAT !!! so our electric P=I 2R distribution could be a huge heater!!!!
5.2.3 Electric energy. Distribution Therefore, in order to transmit high electric power, we have to decrease the intensity by increasing the voltageSo, with high voltage distribution, we lose less calorific energy and thanks to that we can use thinner cables
5.2.3 Electric energy. DistributionBut, how does it work?
5.2.3 Electric energy. DistributionAny transformer is based in the relation between the magnetic field created by two reels that have the same nucleus Nucleus Reel Reel
5.2.3 Electric energy. DistributionThis is the relation between the I and V in each Reel: V1 Nucleus V2Input Output
5.2.3 Electric energy. DistributionWe want V2 as high as possible so we have to increase the number of spirals of the 2º reel (N2) and decrease on N1V1 I 2 N1 V1 N 2 V2 = = ⇒ =V2 I1 N 2 N1 N 2 ↑⇒ V2 ↑
5.2.3 Electric energy. DistributionExercise 5.2.3. Calculate the V2, before and after we increase the number of spirals. I= 20A N1 = 20 N 2 = 40 before and after N 2 = 200 V1 = 400V
5.2.3 Electric energy. Distribution Lets calculate V2 Before AfterV1 I 2 N1 V1 N 2 V2 V1 N 2 = = ⇒ = V2 = =V2 I1 N 2 N1 N1 V1 N 2 400 × 40 400 × 200V2 = = V2 = N1 20 20V2 = 800V N 2 ↑⇒ V2 ↑ V2 = 4000V €
5.2.3 Electric energy. DistributionLets calculate V2 Before AfterV2 = 800V P = VI V2 = 4000V P = VII 2 = 20A P = 800 × 20 I 2 = 20A P = 4000 × 20P = 16000W P = 80000W €
5.2.3 Electric energy. DistributionElectricity arrives at home trough the electric panel that we find close to the entrance door Electric meter HOME
5.2.3 Electric energy. DistributionIn the control panel we find:1º The ICP: This circuit break is placed by your electric company to control that you don’t pass the top consume that you have contracted
5.2.3 Electric energy. DistributionIn the control panel we find:1º The IGA: This circuit break allows us to break the hole circuit with one switch
5.2.3 Electric energy. DistributionIn the control panel we find:1º The Differential switch : This circuit break protects us against a electric discharge
5.2.3 Electric energy. DistributionIn the control panel we find:1º PIA: These circuit breakers control the different circuits that we have at home
5.3 ConsumeIn Spain, we use too much fossil energy to produce electricity
5.1.3 ConsumeThese are the main centrals in Spain
5.3 ConsumeThis is the evolution of the self energy supply for the last 35 years Self energy Year Self Energy Supply Supply 1975 22,6 40 1985 38,9 30 20 1995 28,0 10 1998 25,6 0 1975 1985 1995 1998 2003 2008 2003 22,1 1975-1998:, Fuentes: 2008 21,6 Fuentes: 1975-1998:, 2003: 2008: Ministerio de Industria, Turismo y Comercio[1
5.3 ConsumeThis is the use of the different forms of energy. 2008 consume Coal ; 14,2 Renowable; Oil; 0,4 Gas; 0 28,8 Nuclear; 50 Hydro; 6,5 Fuente de Producción 2007 Producción 2008 2007 % 2008 % 2008/2007 energía (ktep) (ktep) Carbón 5.865 19,3 4.374 14,2 -25,4 Petróleo 143 0,5 127 0,4 -11,2 Gas natural 16 0,1 14 0,0 -10,9 Nuclear 14.360 47,3 15.368 50,0 7,0 Hidráulica 2.342 7,7 2.001 6,5 -14,5 Otras energías 7.624 25,1 8.841 28,8 16,0 renovables Total 30.348 100,0 30.725 100,0 1,2
5.1.1 1º Exercise SolutionInvestigate the energy that these foods have per100 gr:Yogurt 85 kcal Big Mac 498 kcalBread 250kcal Apple 59 kcalBiscuits 450 kcal Orange 58 kcal FantaCereals 400kcal Oil 900kcalChips 234kcal Butter 760 kcal Solution
5.1.1 Energy. Units2º Exercise Solution:• alculate the energy of a Coke in joules. C• alculate the energy measured in kwh that Cwe absorb in 2h when we drink 2 Cokes? Kcal kj kj 1h kjh Kwh138 = 576,84 ⇒ 576,84 ⋅ = 0,16 = 0,16 1Coke 1Coke 1Coke 3600s s 1Coke kwh0,16 ⋅ 2Cockes = 0,32kwh 1Coke
5.1.1 Energy. Units Exercise2º Exercise Solution:• f we use a 100W lamp, and we use Cokes to Iprovide energy, how many Cokes do we needper second?
5.1.2 3 Exercise Forms and Sources3º Exercise:a) Explain the difference between the concepts of source and form of energy.The source of energy is how we get energy, for example the coal or wind; and the form of energy is the type of energy, for example mechanical or nuclear energy.Or more detailedBoth terms are related to energy. Energy is the capacity of an object to do a work, and it can be stored in different forms of energy, like electric, chemical, mechanical, etc. A source of energy is how this form of energy is stored for its use around us. A form of energy is a energy resource, i.e. wind, sun light, etc.So, coal is a source of energy because it store a lot of useful chemical energy liberated when we burn it
5.1.2 3 Exercise Forms and Sources3º Exercise:a) Define the six groups of energy sources, and give four examples of each. Define the six groups of energy sources, and give four examples of each. Renewable (Origin): Inexhaustible sources which can be used continuously. Ex: Wind, waves, sun and firewood. Non renewable (Origin): Exhaustible sources which can be exhausted as years go. Ex: Oil, uranium, natural gas and coal. Traditional (Historical use): This type provides a big amount of global energy. Ex: Hydraulic, coal, uranium and oil. Alternative (Historical use): This type provides energy and it´s easier to obtain than traditional energy. Ex: Wind, solar, biomass and geothermal. Primary (Transformation): This type is obtained from the environment whitout any kind of transformation. Ex: Gas, solar, coal and wind. Secondary (Transformation): This source is obtained after the transformation of a primary source. Ex: Electricity, gas, petrol and oil.
5.1.2 Exercise 5 sol Forms and Sources5º Exercise: Make a list of 20 objects indicating the source of energy used and the energy obtained .For example: TV-Electricity Object Energy Source Energy obtained TV Electricity LightWashing machine Electric energy MechanicalRadiator Electric energy CalorificComputer electric lightFridge Electric energy Mechanical-CalorificToaster Electric energy CalorificBulb Electric energy lightDishwasher Electric energy MechanicalTransformer Electric energy ElectricalFurnace Chemical energy Calorific Back
5.2.1 Exercise Sol. Electric energy. Production1º Exercise:Compare the use of electricity at home with the use of coal, oil, gas, solar, wind, geothermal, uranium.Coal produces a lot of smoke and dust if we use it to heat or cook. Also requires a lot of space to store it.Oil is used to heat houses but is really dangerous if we use it to cook or to create light.Solar energy can be used to heat water, but it doesn’t get really hot. We can use it to cook but it is too slow.Gas is used to cook but it’s quite dangerous and is more difficult to clean. We use it to heat water and houses.Wind, geothermal and uranium can’t be used directly at home, so we need to get electricity from them.
5.2.1 Exercise Sol. Electric energy. Production2º Exercise:What do we mean when we say that the electricity is clean?Electricity is usually defined as clean energy because we can use it at home anytime anyplace. It doesn’t create any dust, gas or smell as does coal, gas or oil.But we have to remember that to create electricity we are different energy sources like coal, oil, nuclear, etc that have several disadvantages like pollution, nuclear waste, environment destruction, etc. Back
5.2.2 Nuclear Power StationsNuclear power station Nuclear Turbine Mechanical Steam Energy Steam Boiler Cold Generator Water Electricity Heat Cooling Uranium TransformerMine Reactor High Volt Pylons
5.2.2 Hydro Power StationsThe water from the river is stored in a dam. The water is released has high energy thanks to the height, so it moves the turbine. The mechanical energy obtained is transformed into electricity inside the generator. This electricity is transformed into high voltage electricity in a transformer. This electricity is connected to the pylons and transmitted to the electric grid Mechanical Energy Turbine Generator Water Transformer high High Volt pressure Water River Dam Water Pylons River Back
5.2.2 Solar Tower Power StationsSolar Tower power station Back Steam Turbine Mechanical Energy Steam Boiler Cold Generator Water Electricity Light Cooling Light TransformerSun Heliostats High Volt Pylons
5.2.2 Photovoltaic Power StationsPhotovoltaic power station Back Pylon High Voltage current Transformer Alternate Current Light ElectricSun Solar panel current Inverter photovoltaic
5.2.2 Wind Power StationsWind power station Back Multiplied Mechanical Energy Gear Box Generator Electricity Mechanical energy TransformerWind Rotor High Volt Mechanical energy Pylons
5.2.2 Tide Power StationsTide Power Station Back Mechanical Generator Energy Turbine Water Transformer high High Volt pressure Sea Dam Water Tide Pylons Water raise
5.2.2 Biomass Power StationsBiomass power station Back Turbine Mechanical Steam Energy Steam Boiler Cold Generator Water Electricity Heat Cooling TransformerBiomass Furnace High Volt Bio fuel Pylons
5.2.2 Geothermal Power StationsGeothermal power station Back Steam Turbine Mechanical Energy Steam Lava Generator ElectricityWater Cold Cooling Water TransformerWater High Voltpump Pylons
5.2.3 Electric energy. DistributionExercise 8Calculate the % of energy wasted in calorific energy when we transport 1250 kw with a cable that has 10 Ohm if: Voltage is 250kV Voltage is 25 KV 2 Pabsolute = VI ; Pcalorific = I R ; V = IR Pabsolute − Pcalorific Ploss% = x100 Pabsolute
5.2.3 Electric energy. DistributionExercise 8Calculate the % of energy wasted in calorific energy when we transport 1250 MW with a cable that has 10 Ohm if: Voltage is 250kW
5.2.3 Electric energy. DistributionExercise 8Calculate the % of energy wasted in calorific energy when we transport 1250 MW with a cable that has 10 Ohm if: Voltage is 25 KV