1、Life Cycle Assessment LCAWhy LCA?uQuantify the environmental impact of a product or process*uAnswer questions about product life cyclesuCompare two alternatives - which is greener?uIdentify the harmful stages of the life cycle *or carry out a qualitative assessment quick but subjectiveThe LCA system
2、+ TransportExtraction of materialsProcessing of materialsManufacture and assemblyUse and maintenanceReuse and recyclingWaste managementENERGYRAWMATERIALSEMISSIONSTO AIREMISSIONSTO WATERSOLIDWASTEUTILITY (FUNCTION)system boundaryStages of an LCA: 1 goal, scope and unitsExample electric and disposable
3、 razors- why are we doing it?- what is the system?- what is the functional unit?- to improve designs- manufacture, use and disposal- 1 years close shaves at 1 per dayThe system processes - flowchartsExample: wooden tableuIdentifies the system boundaryuFlows in and out materials, energy (E) and trans
4、port use (T)uShows all the processes involved in the life cycleuExcludes selected processes e.g. minor ones, or unknownuShows end-of-life alternatives, with probabilityFlowchart exercise 1: electric shaverSteel productionManufacture and assemblyDistribution UseShaver disposalLandfillEMISSIONSTO AIRE
5、MISSIONSTO WATERSOLIDWASTEUTILITY (shaving)system boundaryUK Elec. generationETransportTPolymer productionElectronics productionRecycling30%70%EEETPackaging productionwhats missing?TFlowchart 2: disposable razor & bladesSteel productionManufacture and assemblyDistribution UseRazor disposalLandfillEM
6、ISSIONSTO AIREMISSIONSTO WATERSOLIDWASTEUTILITY (shaving)system boundaryUK Elec. generationETransportTPolymer productionETPackaging productionwhats missing?TBladesEHot waterSoapThe functional unit uMilk packaging methods Goal of study: to compare packaging materials and designs from dairy to consume
7、r, including disposal.Functional unit: 1000 litres of packed milk, for one trip.uLight bulbs Goal: to compare alternative light bulb designs for consumers.Functional unit: 10,000 hours illumination at a given brightness (x lumens).uCommuting Goal: to compare different modes of transport to work, e.g
8、. bus, bike, carFunctional unit: 1 years commuting 10km/day by 100 peopleExercises:uFood transport (to compare road and rail for food from farm to supermarket)uHouse design (to compare the energy and materials use of alternative designs)uRefrigerators (to compare different models of various sizes)Fo
9、od transport: 100 ton.kmHouse design: 500m2 dwelling in a specified climateRefrigerator: 2m3 volume, cooled by 20 for 1 year, 5kg food added/weekStage 2: Inventory analysisA complete record of quantities of:uInputs of energy, fuel, etc.uRaw materials by typeuTransport used (hence fuels, energy, etc)
10、uOutputs to air, water; solid waste - many chemicals listed hereThe inventory is normally a spreadsheet or table of many entriesExample: shaving systemsInventory of processes includes:uPolymers from oil; copper; etc.utransport energy and emissionsudisposal solid waste and air pollutionStage 3: Impac
11、t assessmentThe inventory is usually translated into a set of environmental effects:Fuels & energyRaw materials(Land)(Water)Solid wasteAir: CO2, NOX, SOX, etc.Water: Acid, nitrates, phosphates, etc.Waste heatUse of non-renewable resourcesGlobal warmingOzone depletionHuman toxicityEcosystem toxicityA
12、cidificationEutrophicationCOD, BOD in waterSmogNoise. etc.?Impact assessment - classificationThe correspondence between inventory (aspects) and effects is not one-to-one:Fuels & energyRaw materials(Land)(Water)Solid wasteAir: CO2, NOX, SOX, etc.Water: Acid, nitrates, phosphates, etc.Waste heatUse of
13、 non-renewable resourcesGlobal warmingOzone depletionHuman toxicityEcosystem toxicityAcidificationEutrophicationCOD, BOD in waterSmogNoise. etc.Impact assessmentExampleImpact of electric shaver:uresource depletion (oil, copper)uglobal warming (CO2) from elec.utoxicity from transport emissionsuetc.Im
14、pact of razor & blades:uglobal warming (CO2, CH4)uEco-toxicity from waste wateruLand use from landfill of waste inc. packaginguetc.Impact assessment - characterisationGreenhouseOzoneAcidificationEutrophicationHeavy metalsCarcinogensWinter smogSummer smogThe totals for each effect can then be added u
15、p and compared:Impact assessment - valuationuThe last stage, optional - and controversialuIf subjective values are placed on health, ecosystems, etc. - then the impacts can be valued in a single unituMost common example: Dutch Ecoindicator method suggests relative importance of impacts the whole LCA
16、 can be expressed in terms of Points only valid for a country or region, e.g. EC good for internal comparisons; used by PhilipsuE.g. Electric shaver250 points to make, 1 to charge= 2 pts per shave Razor & blades30 pts handle, 12 per cartridge= 3 pts per shaveStage 4 interpretation Example: shavingIn
17、terpreting the study:Electric shaver - major impact in manufacture and charging, hence large GW impactRazor and blades more waste, depending on assumptions on blade durability, method of heating waterhence better understanding and design ideasLCA softwareuDatabase contains inventory for common mater
18、ials, energy sources, transport types and waste strategiesdata quality is important; is it reliable?uCan carry out impact assessment if desireduEasy software: EcoIT,for products and packaging; see http:/www.pre.nl/eco-it/default.htmuMore detailed: Simapro Both from (Pre Consultants, NL) using Ecoindicator method for valuation. See www.pre.nl
