Eco Audit White Paper. - Granta Design

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Figure 2.Despite the formalism that attaches to LCAmethods, the results are subject toconsiderable uncertainty. Resource andenergy inputs can be monitored in astraightforward and reasonably precise way.The emissions rely more heavily onsophisticated monitoring equipment—few areknown to better than 10%. Assessments ofimpacts depend on values for the marginaleffect of each emission on each impactcategory; many of these have much greateruncertainties. Moreover, a full LCA is timeconsuming,expensive, and requires muchdetail, and it cannot cope with the problemthat 80% of the environmental burden of aproduct is determined in the early stages ofdesign when many decisions are still fluid.LCA is a product assessment tool, not adesign tool.And there is a further difficulty: what is adesigner supposed to do with these numbers?The designer, seeking to cope with the manyinterdependent decisions that any designinvolves, inevitably finds it hard to know howbest to use data of this type. How are CO 2 andSO x productions to be balanced againstresource depletion, energy consumption,global warming potential, or human toxicity?This perception has led to efforts to condensethe eco information about a material’sproduction into a single measure or indicator,normalizing and weighting each source ofstress to give the designer a simple, numericranking. The use of a single-valued indicator iscriticized by some on the grounds that there isno agreement on normalization or weightingfactors and that the method is opaque sincethe indicator value has no simple physicalsignificance.On one point, however, there is a degree ofinternational agreement: a commitment to aprogressive reduction in carbon emissions,generally interpreted as meaning CO 2 . At thenational level the focus is more on reducingenergy consumption, but since this and CO 2production are closely related, reducing onegenerally reduces the other. Thus there is acertain logic in basing design decisions onenergy consumption or CO 2 generation; theycarry more conviction than the use of a moreobscure indicator, as evidenced by the nowstandardreporting of both energy efficiencyand the CO 2 emissions of cars, and theenergy rating and ranking of appliances. Weshall follow this route.The need, then, is for a product-assessmentstrategy that addresses current concerns andcombines acceptable cost burden withsufficient precision to guide decision-making.It should be flexible enough to accommodatefuture refinement and simple enough to allowrapid “What-if” exploration of alternatives. Toachieve this it is necessary to strip-off much ofthe detail, multiple targeting, and complexitythat makes standard LCA methods socumbersome.Figure 2. Typical LCA output showing three categories:resource consumption, emission inventory, and impactassessment (data in part from reference (4)).The CES EduPack Eco Audit Tool 2 © 2012, Granta Design
3. The approachThe approach developed here has threecomponents.1. Adopt simple measures ofenvironmental stress.Section 2 points to the use of energy or CO 2footprint as logical choices for measuringenvironmental stress, rather than combinedindicators. If we wanted to pick just one ofthese, energy has the merit that it is theeasiest to monitor, can be measured withrelative precision and, with appropriateprecautions, can when needed be used as aproxy for CO 2 .2. Distinguish the phases of life.Figure 3 suggests the breakdown, assigning afraction of the total life-energy demands of aproduct to material creation, productmanufacture, transport, and product use anddisposal. Product disposal can take manydifferent forms, some carrying an energypenalty, some allowing energy recycling orrecovery. When this distinction is made, it isfrequently found that one of phases ofFigure 3. Breakdown of energy into that associated witheach life-phase.Figure 1 dominates the picture. Figure 4presents the evidence. The upper row showsan approximate energy breakdown for threeclasses of energy-using products: a civilaircraft, a family car, and an appliance: for allthree the use-phase consumes more energythan the sum of all the others. The lower rowshows products that require energy during theuse-phase of life, but not as intensively asthose of the upper row. For these, theembodied energies of the materials of whichthey are made often dominate the picture.Two conclusions can be drawn. The first: onephase frequently dominates, accounting forFigure 4. Approximate values for the energy consumed at each phase of Figure 1 for a range of products (data fromrefs. (5) and (6)). The disposal phase is not shown because there are many alternatives for each product.The CES EduPack Eco Audit Tool 3 © 2012, Granta Design
Page 2 and 3: Contents1. Introduction ...........
Page 6 and 7: 60% or more of the energy—often m
Page 8 and 9: combustion, not an option for steel
Page 10 and 11: Figure 8. The 1 st -life energy and
Page 12 and 13: ecycle energy and recycle fraction
Page 14 and 15: Figure 12. The energy and carbon ba
Page 16 and 17: A portable space heaterThe space he
Page 18 and 19: 6. Summary and conclusionsEco aware
Page 20 and 21: Eco Audit ReportProduct NameBottled
Page 22 and 23: Use:Energy and CO2 SummaryStatic mo
Page 24: Dead weight (100 litres of water) 1

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