Paper_Clip_Tutorial Part1.pdf - GaBi Software

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2.3.2 Selection of Impact Categories Conducting Life Cycle Assessments A number of impact categories are typically chosen as the focus of an LCA study. This choice of impact categories depends on the goal of the study. The selected impact categories should cover the environmental effects of the analyzed product system. The choice of impact categories and the choice of the impact assessment method should be documented in the goal and scope definition. 2.3.3 Classification The results of the Life Cycle Inventory phase include many different emissions. After the relevant impact categories are selected, the LCI results are assigned to one or more impact categories. If substances contribute to more than one impact category, they must be classified as contributors to all relevant categories. For example, CO2 and CH4 are both assigned to the impact category “global warming potential”. NO x emissions can be classified to contribute to both eutrophication and acidification and so the total flow will be fully assigned to both of these two categories. On the other hand, SO2 is apportioned between the impact categories of human health and acidification. Human health and acidification are parallel mechanisms and so the flow is allocated between the two impact categories. 2.3.4 Characterization Characterization describes and quantifies the environmental impact of the analyzed product system. After assigning the LCI results to the impact categories, characterization factors have to be applied to the relevant quantities. The characterization factors are included in the selected impact category methods like CML or TRACI. Results of the LCI are converted into reference units using characterization factors. For example, the reference substance for the impact category “global warming potential” is CO2 and the reference unit is defined as “kg CO2-equivalent”. All emissions that contribute to global warming are converted to kg CO2-equivalents according to the relevant characterization factor. Each emission has its own characterization factor. Figure 10: Characterization Example Figure 10 shows the classification and characterization of methane according to CML 22
3.0E-11 2.5E-11 2.0E-11 1.5E-11 1.0E-11 5.0E-12 0.0E+00 GWP 100 Year [-] Conducting Life Cycle Assessments 2001 with the characterization factor from December 2007. Methane contributes to the global warming potential (GWP). Therefore, during the classification step, methane is classified as a contributor to the global warming potential impact category. According to the CML method, methane has a characterization factor of 25. This means that CML has determined that methane contributes 25 times more than carbon dioxide to the global warming potential when a time frame of a hundred years is taken into account. The 6 kg of CH4-emissions in this example contribute 150 kg CO2-equivalents to the total GWP. 2.3.5 Optional elements of an LCA Normalization, evaluation, grouping and weighting are all optional elements that are performed to facilitate the interpretation of the LCIA results. It is essential that these actions are transparently documented since other individuals, organizations and societies may have different preferences for displaying the results and might want to normalize, evaluate, group or weight them differently. 2.3.5.1 Normalization Normalization involves displaying the magnitude of impact indicator results relative to a reference amount. For example this can be done for comparison with a reference system. The impact potentials quantify the potential for specific ecological impacts. In the normalization step the impact category results are compared to references in order to distinguish what is normal or not. For the normalization, reference quantities for a reference region or country (e.g. Germany) during a time period (e.g. 1 year) are used. This could be, for example, the overall emission of CO2-equivalents in Germany within one year, or, the CO2-equivalents of one person in Western Europe per year. When the results of all impact categories are compared to their references, they can be compared to each other more easily, since it is possible to say which impact indicator result contributes more or less to the overall entity of this impact category. Figure 11 shows impact categories normalized for different regions. ODP [-] AP [-] EP [-] POCP [-] Figure 11: Normalized impact categories for different regions 23 USA North America World
Page 1 and 2: GaBi Paper Clip Tutorial Part 1 Int
Page 3 and 4: Table of Contents 1 Introduction to
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Page 7 and 8: Nomenclature Abbreviation Explanati
Page 9 and 10: Introduction to Life Cycle Assessme
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Page 27 and 28: • weighting procedure 2.4.5 Criti
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Page 31 and 32: 7. You can close this model. Proced
Page 33 and 34: Procedure 07 Creating a plan and ad
Page 35 and 36: 07.04 Searching for processes Proce
Page 37 and 38: Procedure 08 Creating a new process
Page 39 and 40: Procedure energies is avoided by th
Page 41 and 42: Procedure 09.04 Inputs and outputs
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Page 47 and 48: Procedure The reference quantity of
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Page 51 and 52: Procedure Make sure that each of th
Page 53 and 54: Procedure 13 Using auto-connect and
Page 55 and 56: 13.04 Adding a transport process Pr
Page 57 and 58: 14 Linking processes Procedure Let
Page 59 and 60: 15 Adding a plan to a plan Procedur
Page 61 and 62: Procedure and recycling processes o
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Page 65 and 66: 17.02 GaBi Dashboard Procedure The
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19 Working with the balance tab 19.
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Procedure sea water, agricultural s
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Procedure The balance window now di
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20 Analyzing weak points Procedure
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21 Exporting results and charts Pro
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Procedure From the dashboards, simp
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Appendix A Appendix A Description o
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The acidification potential is give
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Appendix A effects are changes in g
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Appendix A Appendix A 9 Abiotic Dep
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