GaBi EDU. Handbook to Explain LCA Using the GaBi EDU Software Package

Transcription

1 GaBi EDU Handbook to Explain LCA Using the GaBi EDU Software Package

2 Title of the Study: Client: August 2009 Authors: Matt VanDuinen Nicole Deisl PE AMERICAS LLC 344 Boylston Street, 3 rd Floor Boston, MA Phone +1 (617) Fax +1 (617) Internet [email protected]

3 Table of Contents Table of Contents 1 Introduction to LCA What is LCA? Who uses an LCA? Industry Government Universities How is an LCA created? Performing of an Life Cycle Assessment Goal and Scope Goal Scope Inventory Analysis Data collection - Classifications Data calculation - Issues Life Cycle Impact Assessment Overview Methods Selection of impact categories Classification Characterization Optional elements of an LCA Interpretation Identification of significant issues Evaluation Conclusions, recommendations and reporting Report Critical Review Using an LCA Software to Create Models Overview of GaBi Getting Started Databases Creating a New Database Connecting a Database Using the Database Deactivating the Database Projects Plans Creating a New Plan

4 Table of Contents Plan Tools Processes Finding a Process Using a Process Linking Processes Creating a Process Flows Using Flows Create new Flows Finishing the Example Transportation Use Phase End-of-Life Final Touches Balances and Outputs Create a New Balance Inputs and Outputs Process Results Quantity View Weak Point Analysis Relative Contribution Creating a Graph Exporting to Excel Comparing Models Bibliography

5 Table of Figures Table of Figures Figure 1: Overview of Life Cycle Assessment... 9 Figure 2: Steps of a Life Cycle Assessment According to ISO Figure 3: Process Flow Diagram Figure 4: System Boundaries Figure 5: Allocation Example Figure 6: Data Collection and Calculation Process Figure 7: Example Data Collection Sheet Figure 8: Example of Classification and Characterization Figure 9: Classification and Characterization Process Figure 10: Comparison of the TRACI and CML Methods Figure 11: Characterization Example Figure 13: Weighting Factors for EcoIndicator Figure 12: Normalization Example Figure 14: GaBi start screen Figure 15: Creating a Database Figure 16: New Database Window Figure 17: Connect a Database Window Figure 18: Project Window Figure 19: Creating a New Plan Figure 20: Plan Tools Figure 21: Life Cycle Steel Paperclip Plan Figure 22: Finding a Process Figure 23: GaBi Search Window Figure 24: Process Window Figure 25: New Process Window Figure 26: Natural Gas Flow Figure 27: Flow Search Window Figure 28: No Flow Found Window Figure 29: New Flow Window Figure 30: Updated Process Window Figure 31: Updated Plan View

6 Table of Figures Figure 32: Final Plan View Figure 33: Balance Window Figure 34: Input Table Figure 35: Weak Point Analysis Figure 36: Results Graph Figure 37: Results in Excel

7 Nomenclature Nomenclature Abbreviation Explanation AP CML LCA LCI LCIA EP GWP POCP ODP ISO TRACI Acidification Potential Centre of Environmental Science, University of Leiden, the Netherlands Life Cycle Assessment Life Cycle Inventory Life Cycle Impact Assessment Eutrophication Potential Global Warming Potential Photochemical Ozone Creation Potential Ozone Depletion Potential International Organiztion of Standardization Tool for the Reduction and Assessment of Chemical and other Environmental Impacts 7

8 How this handbook is written How this handbook is written This handbook provides general information about the backgrounds of the Life Cycle Assessment methodology in Chapter 2. In Chapter 3 the handbook provides practical advice on how to perform LCA studies with a LCA-software. In this handbook the GaBi education database is used for a first introduction how to you use a softweare for generating an LCA study. The GaBi Education uses a paper clip example. 8

9 Introduction to LCA 1 Introduction to LCA Along with this section in the handbook, please see the first video in the series accompanying GaBi EDU which will also briefly explain LCA. Figure 1: Overview of Life Cycle Assessment 1.1 What is LCA? Life Cycle Assessment (LCA), as defined by the ISO and ISO standards, is the compiling and evaluation of the inputs and outputs and the potential environmental impacts of a product system during its lifetime. 1.2 Who uses an LCA? Life Cycle Assessments are used by a variety of different users for a variety of different purposes. According to the ISO Standard on LCA, it can assist in: Identifying opportunities to improve the environmental aspects of products at various points in their life cycle Decision making in industry, governmental, or non-governmental organizations (e.g., strategic planning, priority setting, product or process design or redesign) Selection of relevant indicators of environmental performance, including measurement techniques Marketing (e.g., an environmental claim, eco-labelling scheme or environmental product declaration) The following is just a brief list of the groups that use LCAs and the possibilities that an LCA could be used for. 9

10 Introduction to LCA Industry A lot of large companies use LCAs and include it in their environmental management strategies. LCA studies are also performed by industry associations and Environmental Concepts and Tools research organizations (e.g., Canadian Wood Council, International Copper Association, International Lead and Zinc Research Organization, International Iron and Steel Institute, International Aluminum Institute and the Nickel Development Institute) Government Governmental departments around the world have been actively promoting LCA. For governments, LCA is useful in developing more effective environmental policies related to materials and products Universities There are many universities which are performing different LCA activities and research. For example, LBP University of Stuttgart Department of Life Cycle Engineering, École Polytechnique de Montréal s Interuniversity Reference Center for the Life Cycle Assessment (CIRAIG), University of Toronto, Queens Universi, the University of Calgary, Carnegie Mellon University, and Royal Melbourne Institute of Technology are leading institutions researching the application and methodology of LCA. 1.3 How is an LCA created? There are two ISO standards designed for LCA application, the ISO and The ISO is an introduction to LCA and contains definitions and a background to LCA. ISO describes the process to creating an LCA and the steps involved. In Chapter 2 the creation of a Life Cycle Assessment is described according to the ISO standards and

11 Performing of an Life Cycle Assessment 2 Performing of an Life Cycle Assessment Life Cycle Assessments are performed according to the ISO and standards. LCAs consist of four steps, as shown in Figure Goal and Scope 2. Inventory Analysis 3. Impact Assessment 4. Interpretation The four steps of the LCA are described in detail in the chapters below. Figure 2: Steps of a Life Cycle Assessment According to ISO Goal and Scope The first phase of an LCA is the definition of the goal and scope according to the ISO standard. In this step all general decisions for setting up the LCA system are made. The goal and scope should be defined clearly and consistently with the intended application. An LCA is an interactive process and this allows redefining the goal and scope later in the study, based on the interpretation of the results Goal In the goal definition, the following points need to be determined: 11

12 Performing of an Life Cycle Assessment The intended application for the study - An LCA can be intended for many different applications like marketing, product development, product improvement, strategic planning, etc. The reasons for carrying out the LCA study - These can also vary greatly and depend on the depth of the study. If the study is intended to be published, then more time is going to be allocated to a review process and more data will be collected for a more complete study. If the LCA will be used internally, no critical review is necessary and the company can go as deep into the study as it wants to. The intended audience for the LCA report The audience can be the shareholders, executives, engineers, consumers, etc Scope In this step of the Life Cycle Assessment process, the product itself and all assumptions are described, as well as the methodology used to set up the product system. The following sections describe a list of factors that need to be determined before creating an LCA. Function of the system Functional unit Description of the system System boundaries Allocation procedures Impact categories and the impact model Data requirements Data assumptions Limitations Data quality requirements Peer review Reporting type The most important issues are described in detail in the sections below. For further information please refer to the ISO standard and Function of the System To describe a product, the function of it has to be described. A system can have many functions and the one chosen depends upon what the goal of the LCA is. For example, an aluminum can has a mass, a volume and other characteristics to guarantee that soda is bottled and can be distributed, sold, and consumed. That s the function of the can Functional Unit The functional unit is the mathematically quantified definition of the function of a product system. The functional unit for the aluminum can could be 12 oz. Or, for the comparison of two products the functional unit is the equivalent unit, for example 1000 liters of milk packed in glass bottles or packed in carton. In general, defining a functional unit can be quite difficult, because the performance of products is not always easy to describe. 12

13 Performing of an Life Cycle Assessment After defining a functional unit, a reference flow has to be defined. The reference flow is the measure of product units and materials needed to fulfill the function, as defined by the functional unit. All collected data of the inventory phase is related to the reference flow. It means that all data used to perform a study must be calculated to represent this flow System Boundaries The system boundary defines the unit processes which can be included or excluded in the system. Ideally, the inputs and outputs that cross the boundaries of the product system are elementary flows. Elementary flows are energy or material flows that are not refined by any technical process, but enter or leave the system directly to/from the nature, e.g. crude oil, air, heat, non-refined minerals, as well as emissions and effluents that are released into the environment. The unit process is the smallest portion of a product system for which data is collected. Examples are individual production processes, production lines, cradle-to-gate systems for components, transports etc. It is often helpful to describe the system using a process flow diagram showing the unit processes and their relationships. Figure 3 shows a process flow diagram with all included processes. Figure 3: Process Flow Diagram The system boundaries are defined by cut-off criteria. Cut-off criteria allow defining which parts and materials of the product system will be included in the system, and therefore are 13

14 Performing of an Life Cycle Assessment taken into account, as well as defining which are excluded and cut off from the system. For example, the cut-off criteria can integrate all parts of a product system that contribute more than 5% to the overall weight. Other criteria might include the number of processing steps or the estimated contribution of materials or processes to the estimated overall environmental impact. There are four main options to define the system boundaries used (shown in Figure 4): Cradle to Grave: includes the materials and processes from raw material extraction through production, transportation, use, and end-of-life; used for a product s full environmental footprint Cradle to Gate: includes the materials and processes from raw material extraction through the production phase (gate of the factory); used to determine a product s environmental footprint from the creation of that product Gate to Grave: includes the materials and processes from the use and end-of-life phases (everything post-production); used to determine the environmental footprint of a product once it leaves the factory Gate to Gate: includes the materials and processes from the production phase only; used to determine the in-house footprint of a company Figure 4: System Boundaries The ISO standard has more information on what to include in the boundaries of the system. 14

15 Performing of an Life Cycle Assessment Allocation Procedures In many cases, more than one product is produced. In such cases, it is necessary to divide the environmental impacts from the processes between the products. This is what allocation is used for. The environmental impacts of various products and by products can be divided up to reflect the relative contribution based on a certain characteristic. The impacts can be allocated to the different products using one of the rules defined below. Allocation by Mass: The impacts are ascribed to all products according their mass. For example, if the plastic bottle has a weight of 75 g and the cap 25 g, the bottle would be allocated 75% of the impacts, and the cap would have 25%. Allocation by Heating Value: The impacts are ascribed to all products according their heating value. The same methodology applies as that of the mass allocation. If the bottle s heating value is 50% of the total heating value, it is allocated 50% of the impacts. Allocation by Market Value: The impacts are ascribed to all products according to their market value. If the bottle accounts for 60% of the market value, it gets 60% of the impacts allocated to it. Allocation by Other Rules: This can include exergy, substance content, etc. All are allocated based upon the same methodologies used above. Figure 5 shows an example process with different allocation methods. Figure 5: Allocation Example Data Quality Requirements Data quality requirements define the properties of the data for the study. Descriptions of data quality are important because the data quality has a significant influence of the results of the LCA study. The requirement of data quality has to be determined at the beginning of the study as it is needed for the data to be useful and reliable. The reliability of the results of the LCA study is highly dependent on the reliability of the data the results are derived from. Data quality may be defined as characteristics on data that bear on their ability to satisfy stated requirements. The quality of a dataset can only be assessed if the characteristics 15

16 Performing of an Life Cycle Assessment of the data are sufficiently documented. Data quality does therefore in many respects correspond to documentation quality. The following issues should be considered for the data quality: Data acquisition: Is the data measured, calculated or estimated? Precision Completeness: How high is the amount of primary data (in %) Representativity, consistency, reproducibility Time-reference of the data Geographical reference of the data (local, regional, global) Technology (BAT) In GaBi you can define a profile of the data you would like to get. In that profile, you can define your preference for: Nation Year (time of data collection) Completeness Allocation 2.2 Inventory Analysis General Inventory Analysis is the LCA phase involving the compilation and quantification of inputs and outputs for a given product system throughout its life cycle. The Inventory Analysis includes data collection and data calculation procedures. The data collection should be done for every unit process which is included in the system boundary. The collected and calculated data quantify the relevant inputs and outputs of a product system. Process inputs are raw materials, energy, products, or semi-finished products which are outputs from other processes. Process outputs are emissions, products, semi-finished products, or energy which are either emitted to nature or used in another process. 16

17 Performing of an Life Cycle Assessment Figure 6: Data Collection and Calculation Process Figure 6 shows a simplified Process of data collection and calculation. The process of conducting an inventory analysis is iterative. As data is collected and more is learned about the system, new data requirements or limitations may be identified that require a change in the data collection procedures so that the goal of the study will still be met. Sometimes, issues may be identified that require revisions to the goal or scope of the study. After all the data is collected, an LCI will be created. The LCI is essentially a table listing all of the material and energy inputs and outputs. Detailed information of data collection and calculation can be found in the ISO Data collection - Classifications This phase is the most work intensive and time consuming of all the phases in an LCA. It includes collecting quantitative and qualitative data for every unit process in the system. The data for each unit process can be classified under major headings, including energy inputs co-products raw material inputs waste ancillary inputs emissions to air other physical inputs discharges to water and soil products other environmental aspects Practical constraints on data collection should be considered in the scope and documented in the study report. 17

18 Performing of an Life Cycle Assessment Figure 7 shows a simple diagram which can be used to support data collection. It allows the user to enter the various input and output flows with the relevant quantities. Figure 7: Example Data Collection Sheet Data calculation - Issues The data calculation includes the following three issues: The validation of the collected data has to be a continuous process. This can be done with mass or energy balances as well as with a comparison with similar data. Also, methods have to be in place on how to handle missing data and data gaps. The data have to be related to unit processes The data have to be related to the functional unit. These steps are necessary to generate the results of the inventory of the defined system for each unit process and for the defined functional unit of the product system that is to be modeled. The data calculation can be done with an LCA software like GaBi. There, the relation to the unit process and the functional unit can be done automatically. This is described in detail later in the handbook when you are taken through a walkthrough in GaBi. 18

19 Performing of an Life Cycle Assessment 2.3 Life Cycle Impact Assessment Overview The Life Cycle Impact Assessment (LCIA) identifies and evaluates the amount and significance of the potential environmental impacts from the results of the life cycle inventory. Characterization factors and impact categories are used to measure the impact of certain emissions from the study. In this process, the long list of substances generated by the life cycle inventory is converted into a few environmental impacts, which are easier to interpret. Figure 8 shows the conversion from emissions to impact potentials via classification and characterization. Figure 8: Example of Classification and Characterization Impact categories are scientific definitions of which substances contribute to a certain environmental problem. For example, the problem of global warming is represented by the global warming potential impact category. Any substance that contributes to the global warming potential, such as carbon dioxide and methane, are then classified as contributors. The impact categories provide indicators of potential environmental impacts. Characterization factors are factors derived from a characterization model which is applied to convert an assigned life cycle inventory analysis result to the common unit of the category indicator. They are determined by different scientific groups based on different methodologies and philosophical views of the problems discussed. Two of the most widely used impact category methodologies are TRACI in the US, and CML in Europe. The Life Cycle Impact Assessment includes several steps, according to the ISO standard, and can be found in more detail in the ISO standard

20 Performing of an Life Cycle Assessment Within the scope of a study, certain elements are decided upon that deal with the LCIA. Mandatory elements include the selection of relevant impact categories, classification, and characterization. The optional elements of the study are normalization, grouping and weighting. Figure... shows the process of classification and characterization in the LCIA step with the example of the acidification. All acidifying emissions, like NOx and SO2, of the LCI are assigned to the impact category acidification. This step is called classification. The inventory flows are classified according to their potential impact on the environment or human health. These categories determine indicators of potential environmental impacts. After the classification the LCI results are converted into common units. This means, the effect on the environment in each impact category is quantified through category indicators, e.g. proton release (H+ aq.) in the case of acidification or for the global warming potential kg CO2 equivalents. Example Life cycle inventory results Cd, CO 2, NO x, SO 2, etc. (kg/functional unit) Impact category Acidification LCI results assigned to impact category Acidifying emissions (NO x, SO 2, etc. assigned to acidification) Characterisation model Category indicator Proton release (H + aq) Environmental relevance Category endpoint(s) - forest - vegetation - etc. Figure 9: Classification and Characterization Process 20

21 Performing of an Life Cycle Assessment Methods There are different methods to perform a Life Cycle Impact Assessment. These methods are developed from different scientific groups and based on different methodologies. This handbook does not explain the development of the different methods but it does describe them. In a Life Cycle Impact Assessment basically two methods are followed: problem-oriented methods (mid points) and damaged-oriented methods (end points). In the problem-oriented methods, flows are classified into environmental potentials to which they contribute. Two problem-oriented methods, TRACI and CML, are described in detail. With the help of these methods the complexity of hundreds of flows are simplified into a few environmental categories. Figure shows the different impact categories used in the CML and TRACI methods. They are based on scientific information and well-proven facts. The amount of subjectivity and uncertainty involved is limited. Figure 10: Comparison of the TRACI and CML Methods 21

22 Performing of an Life Cycle Assessment The damage-oriented methods also start by classifying a system's flows into various environmental themes, but model each environmental theme's damage to human health, ecosystem health, or damage to resources. For example, acidification - often related to acid rain - may cause damage to ecosystems (e.g., in the Black Forest in Germany), but also to buildings or monuments. In essence, this method aims to answer the question: Why should we worry about climate change or ozone depletion? EcoIndicator 99 is an example of a damage-oriented method. The used end points are easier to interpret and communicate. The so-called CML method is the methodology of the Centre for Environmental Studies (CML), University of Leiden, 2001, and focuses on a series of environmental impact categories expressed in terms of emissions to the environment. The CML method includes classification, characterization, and normalization. The impact category indicators of the CML methods are chosen relatively close to the inventory result. For example, the impact categories for the global warming potential and ozone layer depletion are based on IPCC factors. Further information is available at the Centre for Environmental Studies (CML), University of Leiden. For the examples in this document, the CML method is used. Another method is the Tool for the Reduction and Assessment of Chemical and other Environmental Impacts, called TRACI. This problem-oriented method is developed by the U.S. Environmental Protection Agency (EPA) and is primarily used in the US. Further information is available on the TRACI web site: Selection of impact categories In this step, the impact categories and methods are selected. The choice of the impact categories depends on the goal of the study. The selected impact categories should cover the environmental effects of the analyzed product system 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. NOx emissions can be classified to contribute to both ground-level ozone formation and acidification. The total flow will be assigned to both of these two categories. SO2 is apportioned between the impact categories of human health and acidification. These impact categories are parallel mechanisms, and the flow will be allocated between the two impact categories Characterization The characterization describes and quantifies the environmental impact of the analyzed product system. So, after assigning the LCI results to the impact categories, characterization factors have to be defined. The characterization model is included in the selected impact category methods like CML or TRACI. For the characterization the results of the LCI are converted into common units with characterization factors. For example, the im- 22

23 Performing of an Life Cycle Assessment pact category global warming potential has kg CO2 equivalent as the common unit. So, all emissions contributing to the global warming are converted into the unit kg CO2 equivalent by a characterization factor. Figure 11: Characterization Example The principle of characterization is described using the example of CH4 in Figure 11 above. CH4 contributes to the global warming potential. During the classification step, methane is listed with its quantity under the global warming potential section. According to the CML method CH4 has a characterization factor of 21. This means that CML has determined that CH4 contributes 21 times more than carbon dioxide to the global warming potential Optional elements of an LCA Normalization, 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, group, or weight them differently Normalization Normalization is calculating the magnitude of category indicator results relative to reference information. For example, this can be done for comparison with a reference system. Reference information over a given period of time could be area (Germany, Europe, US, the world), person (e.g. US citizen), or product (most frequently used product). The goal of normalization is to better understand the relative amount for each indicator result of the analyzed product system. The impact potentials quantify the potential for specific ecological problems. They are not directly comparable. In the normalization step the relative contribution of each problem can be distinguished. For the normalization, reference flows (RF) are used which are produced for a reference region or country (e.g. Germany) during a time period (e.g. 1 year). 23

24 Performing of an Life Cycle Assessment Figure 12: Normalization Example The results are non-dimensional quantities, which allow comparison of impact potentials Grouping Grouping is the sorting and ranking of the impact categories. It is an optional element with two possible approaches. The impact categories could be sorted on a nominal basis by characteristics such as inputs and outputs or global, regional, and local spatial scales. The impact categories could also be ranked in a given hierarchy, for example in high, medium, and low priority. Ranking is based on value-choices. Different individuals, organizations, and societies may have different preferences; therefore it is possible that different parties will reach different ranking results based on the same indicator results or normalized indicator results Weighting Weighting is also an optional element of the life cycle impact assessment and is based on value-choices and not scientific ones. It s the conversion of the environmental profile into one score. Weighting is aggregating indicator results across impact categories using numerical conversion factors. For example, the basis for weighting factors can be monetary values (willingness to pay, damage costs, and reduction costs) and panel methods (expert panels or non-expert panels). There are two possibilities for weighting. The first method converts the indicator results or normalized results with selected weighting factors. The second method aggregates these converted indicator results or normalized results across impact categories. The EcoIndicator 99 method includes weighting for three endpoints: Impact category Weighting factor Unit Human Health 400 ECO 99 unit/daly Ecosystem Quality 400 ECO 99 unit/pdf m2 yr Resources 200 ECO 99 unit/mj Figure 13: Weighting Factors for EcoIndicator 99 24

25 Performing of an Life Cycle Assessment If the results of the LCIA are, for example 4.5 MJ depleted resources 15 PDF*m2*yr potentially disappeared fraction species 20 person*years of disability for human beings (DALY) They can be presented by using the weighting factors in ECO 99 units. Resource depletion: 4.5 x 200 = 900 ECO 99 units Ecosystem quality: 15 x 400 = ECO 99 units Human health / Disability: 20 x 400 = ECO 99 units The total impact is ECO 99 units. This means that resource depletion contributes to 6% to the total environmental impact. Human health has with 54 % the highest environmental impact (Ecosystem quality: 40%). More information to the EcoIndicator 99 method can be found online. 2.4 Interpretation In the interpretation phase, the results are checked and evaluated to see that they are consistent with the goal and scope and that the study is complete. This phase includes several steps which are described below. The life cycle interpretation is an iterative procedure both within the interpretation phase itself and with the other phases of the LCA. The roles and responsibilities of the different interested parties should be described and taken into account. If a critical review has been conducted, these results should also be described Identification of significant issues The first step of the life cycle interpretation phase is to structure the results from the LCI and LCIA. It also involves reviewing information from the first three phases of the LCA process in order to identify the data elements that contribute most to the results of both the LCI and LCIA for each product, process, or service, otherwise known as significant issues. The results of this effort are used to evaluate the completeness, sensitivity, and consistency of the LCA study (Step 2). The identification of significant issues guides the evaluation step. Because of the extensive amount of data collected, it is only feasible, within reasonable time and resources, to assess the data elements that contribute significantly to the outcome of the results. Significant issues can include: Inventory parameters like energy use, emissions, waste, etc. Impact category indicators like resource use, emissions, waste, etc. Essential contributions for life cycle stages to LCI or LCIA results such as individual unit processes or groups of processes (e.g., transportation, energy production). The results of the LCI and the LCIA phases are structured to identify significant issues. The significant issues should be determined in accordance with the goal and scope definition and interactively with the evaluation. The results can be presented in form of data lists, tables, bar diagrams or other convenient forms. They can be structured after the life 25

26 Performing of an Life Cycle Assessment cycle phases, different processes (energy supply, transportation, raw material extraction etc), type of environmental impact, or other criteria Evaluation The goal of the evaluation is to enhance the reliability of the study. The following three methods should be used for the evaluation: Completeness check: In the completeness check, any missing or incomplete information will be analyzed to see if the information is necessary to satisfy the goal and scope of the study. The preceding phases might need to be revisited to fill the gap, or alternatively the goal and scope can be adjusted. If the decision is made that the information is not necessary, the reasons for this should be recorded Sensitivity check: The sensitivity check determines how the results are affected by uncertainties in the data, assumptions, allocation methods, calculation procedures etc. This element is especially important when different alternatives are compared so that significant differences, or the lack of them, can be understood and reliable. Consistency check: The consistency of the used methods and the goal and scope of the study is checked. Some relevant issues to check can be: data quality, system boundaries, regional and temporal differences, allocation rules and impact assessment. Further information is available in the ISO Conclusions, recommendations and reporting The goal of the life cycle interpretation is to draw conclusions, identify limitations and make recommendations for the intended audience of the LCA. The conclusions are drawn from an iterative loop with the other elements of the interpretation phase in the sequence that follows: Identify the significant issues Evaluate the methodology and results for completeness, sensitivity and consistency Draw preliminary conclusions and check that these are consistent with the requirements of the goal and scope of the study If the conclusions are consistent, report them as the final conclusions. Otherwise return to the previous steps to get consistant conclusions. A thorough analysis of the data quality requirements, the assumptions, and the predefined values need to be made. When the final conclusions of the study are drawn, recommendations to decision-makers are made to reflect a logical and reasonable consequence of the conclusions. Further information is available in the ISO

27 Performing of an Life Cycle Assessment Report The results of the Life Cycle Assessment should be assembled into a comprehensive report to present the results in a clear, transparent and structured manner. The report should present the results, data, methods, assumptions and limitations in sufficient detail. The reporting of the results should be consistent with the goal and scope. The type and format of the report is defined in the scope and will vary depending on the intended audience. If the study extends to the LCIA phase and is reported to a third-party, the following issues should be reported: the relationship with the LCI results a description of the data quality the category endpoints to be protected the selection of impact categories the characterization models the factors and environmental mechanisms the indicator results profile The relative nature of the LCIA results and their inadequacy to predict impacts on category endpoints should also be addressed in the report. Include reference and description of value choices used in the LCIA phase of the study in relation to characterization models, normalization, weighting, etc. Include other requirements given in ISO whenever the study results are intended to be used in comparative assertions intended to be disclosed to the public. Furthermore, in reporting the interpretation phase, ISO requires full transparency in terms of value choices, rationales, and expert judgments. If the results will be reported to someone who was not involved in the LCA study, i.e., third-party or stakeholders, this report will serve as a reference document and should be provided to them to help prevent any misrepresentation of the results. The reference document should consist of the following elements (ISO 1997): 1. Administrative Information a. Name and Address of LCA Practitioner (who conducted the LCA study) b. Date of Report c. Other Contact Information or Release Information 2. Definition of Goal and Scope 3. Life Cycle Inventory Analysis (data collection and calculation procedures) 4. Life Cycle Impact Assessment (methodology and results of the impact assessment that was performed) 5. Life Cycle Interpretation a. Results 27

28 Performing of an Life Cycle Assessment b. Assumptions and Limitations c. Data Quality Assessment 6. Critical Review (internal and external) a. Name and Affiliation of Reviewers b. Critical Review Reports c. Responses to Recommendations Critical Review The ISO requires critical reviews to be performed on all Life Cycle Assessments supporting a comparative assertion disclosed. The type and scope (purpose, level of detail, persons to be involved in the process, etc.) of the critical review are defined in the scope step of the LCA. The review should ensure the quality of the study assuming the following are met: Used methods of the LCA are consistent with the ISO standards Used data are appropriate and reasonable in relation to the goal of the study Limitations are set and explained Assumptions are explained Report is transparent and consistent and the type and style are oriented to the intended audience The critical review can be done by an external or internal expert as well as by a panel of interested parties. 28

29 Using an LCA Software to Create Models 3 Using an LCA Software to Create Models An LCA can be created using LCA software or by manual calculations using a math program or Microsoft Excel. In this handbook, an example LCA is created using the GaBi software created by PE International. This chapter will take you through a step-by-step process of creating an LCA in GaBi while explaining all of the steps and the different objects within GaBi. The example used is the creation of 1000 steel paperclips. If you are following along with the online videos, one thing to note is that the models are in terms of German and European figures since PE International is based out of Stuttgart, Germany. 3.1 Overview of GaBi With features refined through experience on thousands of PE consulting projects, GaBi 4 supports every stage of an LCA, from data collection and organization to presentation of results and stakeholder engagement. GaBi automatically tracks all material, energy, and emissions flows, giving instant performance accounting in hundreds of environmental impact categories. With a modular and parameterized architecture, GaBi allows rapid modeling of even complex processes with thousands of components or dozens of different production options. This architecture also makes it easy to add other data such as economic cost or social impact information to a model, making GaBi a holistic life cycle analysis tool. The GaBi 4 platform is complemented by the most comprehensive, up-to-date Life Cycle Inventory database available. The databases maintained by PE provide over 2,000 cradle-to-gate material data sets, 8,000 intermediary chemical process models, and thousands of LCA projects from quality-controlled industry projects. The data set contained in this educational version is a small fraction of the available data within PE. 29

30 Using an LCA Software to Create Models 3.2 Getting Started To get started using GaBi, please download the GaBi EDU demo version from Run the setup file and follow the onscreen instructions. Once GaBi is installed, open the program. The start screen should look like Figure 14: Figure 14: GaBi start screen The right side of the GaBi start screen contains helpful links dealing with LCA and GaBi. If you would like more information about GaBi, PE International, PE Americas, or LCA in general, this is the place to look. The left side of the start screen contains all of the databases that are connected to the software. Initially, there will be one database labelled Education connected. Don t worry if this isn t the case as we will explain how to connect it later in the handbook. 3.3 Databases Within most LCA software, databases are the primary source of data within the software. These contain all of the datasets, plans, processes, flows, and balances for each project that has been started. 30

31 Using an LCA Software to Create Models Since each database can have different sets of data, a new database should be created for each new project started. This allows the user to see what projects have been started immediately after starting GaBi Creating a New Database Whenever starting a new project, a new database should be created. Some versions of GaBi will have the ability to create preset databases with datasets already included in them, though GaBi EDU does not have that capability. This demo contains a database already so a new database will not need to be created. To create additional databases for different projects, please follow one of the following two steps. The first method to create a new database is to select the type of database you wish to create from the list at the bottom of the right hand side of the GaBi start screen, shown as 1 in Figure 15 below. The second method is to go the Database menu at the top of the window, select Create New Database, then select the type of database you wish to create, shown as 2 in Figure 15 below. 2 1 Figure 15: Creating a Database 31

32 Using an LCA Software to Create Models Once the type of database is selected, the window shown in Figure 16 below will show up. Here, the name of the database is determined and placed in the text box containing New. The database will then be created in a new folder in the directory of your choosing, though the default is in the folder named GaBi 4. Once the name of the database is entered and location chosen, hit OK. Figure 16: New Database Window This will bring up a window asking if you would like to create a new subdirectory with the same title as your new database. Select Yes. Now the new database has been created Connecting a Database Sometimes, a database has already been created but has not been connected to GaBi. This is the case with the GaBi EDU demo project if the Education database was not connected already and shown under the Object hierarchy. This often occurs when multiple people are working on the same project as databases are sent from one person to another. To connect a database, the folder containing the database should be placed into the GaBi 4 folder, located under Program Files on the local hard drive (default is C). Once the folder is placed there, go to the GaBi start page and select Connect database which is either on the bottom right-hand side of the start page under Databases or under the Databases drop-down menu in the top bar. Once this option has been selected, the window shown in Figure 17 should appear. 32

33 Using an LCA Software to Create Models Figure 17: Connect a Database Window In this window, the selection on the left should automatically be on GaBi 4. If you followed the directions from before, the database you wish to connect should be in this folder. If you placed your database in a different folder, locate it on the left. When you find your database, select the folder and hit OK. This should then bring back the GaBi start page with your database listed on the left side in the Object hierarchy. If the database labelled Education is not currently connected, follow the steps to connect it now Using the Database Over time, a number of databases will start to accumulate in your Object hierarchy. GaBi only reads one database at a time though, so after starting GaBi, you need to tell it which database to use. This is done by activating the database you want to use. There are three different ways to activate a database. Click Activate next to the correct database in the bottom right of the GaBi start screen Select the correct database then click Activate under the Database drop-down menu at the top Right-click on the correct database and select Activate After selecting activate from any of the three options, a window will pop up asking for a login. The default name is System and the default password and project are blank. Select OK to activate the database. There is the ability to set protection settings for the databases to require a login name and password but we will not go into this function here as it is rarely used. Please see the GaBi help files if you wish to add protection to your databases. After selecting OK, allow time for GaBi to load all of the objects from the database. This may take anywhere from a few seconds up to a minute depending on the amount of objects in the database. When the database is fully loaded, the hourglass will go away, as well as there being an audible notification. Please activate the Education database now as we will be using it to create our model. Now you will be able to see the full list of objects in the database. In the next few sections of the handbook, many of these will be described. 33

34 Using an LCA Software to Create Models Deactivating the Database Once you are finished working on a project, either you will switch databases or you will close GaBi. In both cases, the current database will be deactivated. When this happens, GaBi s default is to pop-up with two windows. The first asks Do you want to compress the deactivated database now? Select no. The second asks Do you want to save a copy of the deactivated database now? For this question, it is asking whether you would like to make a backup copy in order to have at most one session s work saved in case you would like to go back and undo something you changed. There are three main choices people have here. First, they can just select No and change the same database every time, only having one copy with no worries about undoing work. The second is to select No, and then everyday you work on a project, to go into the GaBi 4 folder on your hard drive and making a copy manually and renaming it as you see fit. The third is to select Yes, in which case GaBi will save a copy of the database in the _DB Backups folder inside the GaBi 4 folder on your hard drive. Any of these three options will then deactivate the database and either activate the new one you selected or close GaBi. 3.4 Projects Within GaBi, projects are a way to organize the newly created plans, processes, and flows that are created for a project. After connecting a database, you should create a project for easy access to the objects created for the model. To do this, you have to click on Projects under the Object hierarchy. Once selected, you can either click on the blank page button on the top left of the window, or right-click on the projects display side on the right then hit new. This will bring up the window shown in Figure 18 below. Figure 18: Project Window Here, you should enter a name for your new project. After entering the name, make sure you click the Activate Project button. Once activated, all of the plans, projects, and flows will be saved under this project. For the tutorial, please create a new project called Life Cycle Steel Paperclip and activate it. 3.5 Plans As with most LCA software, GaBi calculates the potential environmental impacts of a system based on plans. A plan is the way the system being studied is portrayed in the soft- 34

35 Using an LCA Software to Create Models ware. The plan can be an overlying plan of the full system within the boundaries, or it could be of an internal system. Within this tutorial, there are three plans already created. These will show you the general outline of how a plan should look. The rest of this tutorial will be creating a plan for the life cycle of a Steel Paper Clip. The three already there are for a Coated Paper Clip and a Plastic Paper Clip which will be used later in the tutorial, along with a finished plan of a steel paperclip which we will be recreating for practice. Step 2 Step 1 Figure 19: Creating a New Plan Creating a New Plan To start the tutorial, you have to create a new plan where the model for the Steel Paper Clip will be created. There are three different things you can do in order to create a new plan. For all of them, you first have to select Plans from the object hierarchy (shown left). Once selected, you can select the blank page icon located at the top left of the window, or you can right-click in the display area to the right of the Object hierarchy, then select New, or select either Edit- >New. The shortcut key for this is Insert. This will bring up a new plan that you can now edit. The first step is to name your plan. In the top left of the screen there is the default name (New). Click on the text and replace with a name of your choosing. For the tutorial, please enter Life Cycle Steel Paperclip. There are a lot of things you can do within a plan that we will go over in the next few sections as we explain more objects that belong in plans Plan Tools There are a few general plan options that will be useful for every plan created. The first is the New Plan button. This button allows the user quick access to a new plan to include in the previous plan. To make sure your plans are not too crowded, it is recommended that you create plans within plans. A common example of this would be to create an overlying plan for the full life cycle, and within that plan having three separate plans within the overlying plan: production, use, and end-of-life of a product. Of course, more or less plans can be used to fit the needs of the user. Another helpful tool within the plans is the Comment tool. This allows the user to write on the plan without affecting any of the materials or flows. This is mainly used for clarification purposes so the plan can be understood by an outside observer. 35

36 Using an LCA Software to Create Models While you are working on your plan, it is a good idea to save regularly. There is a save button indicated by a floppy disc image, or you can save by going to Object->Save. After entering the name of the plan, please save the plan. Another useful tool is the Balance Calculation button, indicated by purple arrows. We will get into more detail about this later in the handbook. Save Plan Comment Balance Calculation Plan Title New Plan Figure 20: Plan Tools Figure 21: Life Cycle Steel Paperclip Plan Within plans, processes are connected with flows to create your system. In the following section, we will explain what a process is and how to use processes to create models. At this step, your plan should look like Figure 21 above (size of window may be different). 36

37 Using an LCA Software to Create Models 3.6 Processes Within every database is a list of processes used to model an LCA system. Databases within GaBi contain many predefined processes and flows that are used to model LCAs. Every Finding a Process To start creating the steel paperclip, we need steel wire. Within GaBi, there are two different ways to get a process that is needed for the model. GaBi Search Function Process Tree Figure 22: Finding a Process The first is to locate a process using the process tree in the Object hierarchy. Under the Processes tab, there are many groupings where you can manually locate a process based on grouping data. Unless you know exactly where the process is located, this can be very time consuming. A quicker and more efficient way is to use the GaBi search function. The GaBi search function will search for anything you need within GaBi, be it plans, processes, flows, etc. When you are looking for processes only, be sure to have the processes group selected under the Object hierarchy and then click the Search button across the top which is a pair of binoculars. When you click it, the window shown in Figure 23 appears (with the fields blank): To find processes, type in the name or partial name into the first text box and select New search. If you select Start, the search results will be added to the current results that are there. To be safe, you should always use New Search when searching for something. Since we are looking for Steel Wire for our paper clip, perform a search for steel wire. There should be only one process there, but if there are more, please select the one you need, in this case, Steel wire (St). 37

38 Using an LCA Software to Create Models Figure 23: GaBi Search Window If you are already in a plan and need to search for a process, click on the binoculars icon in the plan window. GaBi will automatically assume you are looking for a process and will only search the processes for you Using a Process In order for this process to be useful in the model, it has to be inside the plan. In GaBi, this is as easy as the drag-and-drop process. Simply click and hold the process, dragging it to your plan, and releasing. The process should now be within your plan, allowing you to move it and organize it with respect to the rest of the contents of the plan. At this time, please add the Steel wire process to your plan. Every process will have an input, an output, or both. To check what a process needs to be complete, double click on the process. It will bring up a window like the one in Figure 24. On the left, the Inputs are listed, and on the right, the Outputs. For example, the steel wire process takes in Steel billet and creates Steel wire. More about this will be discussed in the flows section. Next to both the input and outputs is a small red square. Since it is red, it means there is no connection going to that flow and there should be. If it were black, it would signify the connection has been made. If blue, then it signifies a waste product that can have a flow connected. An example of a blue flow would be a recycling process. It would take in a used product and would have the possibility of connecting to a new manufacturing process to create a new product with the recycled material. In order for this process to be complete, we need to find the steel billet and connect that to the steel wire process. At this time, use the GaBi search function with the processes to find the Steel billet process and add that to the plan. If nothing shows up when searching for Steel Billet, try being broader in your search terms. In this case, try searching for Steel and see if you can find a steel billet process. After locating the process, drag it into the plan. In the next section, we will show you how to connect the processes. 38

39 Using an LCA Software to Create Models Inputs Outputs Figure 24: Process Window Linking Processes In order for GaBi to make sure it is using the correct amounts of material for each process, the processes need to be connected and a functional unit set. The functional unit will be explained later in this chapter. Linking processes is simple in GaBi. To start, you have to click on a process you wish to be connected to another one. This will then bring up two vertical bars on each side of the process. The red one on the left is the input bar. The brown on the right is the output bar. To connect two processes, grab the brown bar from the process with the output and place it on the process with the matching input. If both flows are an exact match, it will automatically connect the two processes. If they aren t, then a window will pop up asking which output you want to connect with the corresponding input. Select the source (output) and sink (input) you wish to have connected, and select the name of the flow you wish to use from the flow drop-down menu. Once you have the correct flows selected, please hit ok. This will then connect your two processes. At this time, connect the Steel billet with the steel wire process. The link will show up as an arrow between the two processes. The size of the arrow will depend on the amount of material that is flowing from one process to another. The flow with the most material being transferred will be the largest arrow, and the rest of the arrows will scale relative to that one. The arrows also can be moved and arranged in order for the model to be easily understood Creating a Process To turn the steel wire into a paperclip, we need to bend the wire into the shape of a paperclip. This is going to require a bending process. After searching for this process, you 39

40 Using an LCA Software to Create Models will find that it isn t in the database. This occurs frequently when performing an LCA on a product. Each company will have its own way of creating the product so new processes will need to be created. Since the bending process isn t in the database, we will need to create one. To create a process, go back to the GaBi DB Manager, select Processes in the Object hierarchy and either click the blank page button on the top left or right click on the right side and select New. Both of these will bring up the the window in Figure 25: Figure 25: New Process Window If this isn t what you see, make sure the LCA tab is selected across the top. The first thing to do is to name the process you are creating. Replace New with the name intended. For the tutorial, use Paperclip bending. To the left of the name is a pulldown menu which signifies what nation the process refers to. This is an optional field but it is helpful in making the process more descriptive. The right is the source field. This is used to determine who created the process. We will leave this blank for now. To the right of that is the type field. There are three different types of processes in GaBi: basic, cradle to gate, and partly linked processes. Basic processes are referred to as unit processes in the ISO standard. These processes only contain information about one process step and are considered gate-to-gate processes. This is denoted by b in GaBi. Cradle to gate processes, referred to as system processes in the ISO standard, contain the information about that one process, plus all of the processes upstream of it. The steel billet is an example of this. This is denoted by a blank type in GaBi. 40

41 Using an LCA Software to Create Models Partly linked processes are typically cradle to gate processes with one or more open inputs. The steel wire process that was just added to the plan is an example of this. This is denoted by a pl in GaBi. As you have probably already guessed, the paperclip bending process we are creating is considered a basic process since it is only representing the bending process of the paperclip and nothing else. Please change the type to basic, or b, now. On the bottom, you see the area where the input and output flows are created/placed. This is where the user places the inputs and outputs from the process. For our example, we need to input the steel wire and bend it to form a paperclip, and this process requires electricity. In the next section, we will explain how to add the input/output flows to the process. Save the process at this time. 3.7 Flows Flows are one of the most important objects within GaBi. They represent all the inputs and outputs related to the system. They also are the connections between processes or plans to show the transfer of materials or emissions. There are two main types of flows: elementary and non-elementary. Elementary flows are flows that enter the system from the natural system or flows that leave the system. All natural resources used and emissions to the environment are considered elementary flows. The list of all the input and output flows is considered the Life Cycle Inventory, or LCI. Non-elementary flows are flows that run internally within a plan, going from one process or plan to another. Within GaBi, non-elementary flows must be specified as either tracked or waste flows. When a flow is specified as tracked, signified by an X, it allows the process that the output flow is in to be connected to another process that has the same tracked flow as an input, creating a process chain. On the plan view, the tracked flows should show up on the processes as dots. If you do not see dots in the corners of the processes, please click View on the menu bar at the top and select show tracked inputs/outputs. The dots are red when they aren t connected, and when they do get connected, they turn black. Waste flows, signified by a *, require additional processing within or outside of the current system but that remain in the boundaries. These flows can be connected if the correct processes are present, but do not have to be. For example, many metal processes will have metal scrap that can be recycled, but do not have to be. 41

42 Using an LCA Software to Create Models To see an example of a flow, go to the GaBi Object hierarchy and open up the flow group by clicking on the plus sign next to Flows. Here you will see the different groupings of the flows, whether it be resources, emissions, or other types of flows. We re going to look at the Resources group so please expand that group now, then expand Energy Resources, and finally expand the Non-renewable resources group. To see the flows within a group, you have to select the group you want to look at. Let s look at the Natural gas group now so please select it now. As with a majority of the energy and resource flows within GaBi, there will be a wide range of flows that vary by region. For natural gas, the gas mixture along with the properties vary from region to region so it is important to select the region that most resembles the region the process is being performed in. In cases where the process is performed in multiple regions, you can either choose a region containing all the processes, or create a new plan/process for each region. Figure 26: Natural Gas Flow 42

43 Using an LCA Software to Create Models To gain a better understanding of a flow and what is involved in it, you should open a flow by double-clicking on it. Locate the Natural gas USA flow and double-click on it to open the flow dialog box shown in Figure 26. Within the flow dialog box, you can see if this particular flow is an input, output, or undefined flow. An input or output flow is considered an elementary flow where as an undefined flow is considered a non-elementary flow within the system. The reference quality of most flows is mass, causing the reference unit of the flow to be in kg. The quantities of the flow are listed at the bottom of the flow. These can be considered the properties of a flow. This is also where the contribution to the impact categories is listed. The column labelled 1 kg = * shows the contribution to that specific category from 1 kg of that flow, in this case natural gas. Using the first line for example, 1 kg of natural gas from the USA has MJ of energy (net calorific value). The last column labelled 1 [Quantity] = * kg describes the opposite. Again using the first line for example, to get 1 MJ of energy (net calorific value), you need kg of natural gas from the USA Using Flows Earlier in the walk-through, we created a process for Paperclip bending but there are no inputs/outputs associated with it yet. At this point, we are going to add them to finish our bending process. For each process, a number of input and output flows are going to be used and it depends on the process which ones are used. For our bending process, we have already determined we need steel wire and electricity as inputs, and are going to use them to create a steel paperclip. Under the inputs section, we need to add both of our inputs. To do this, enter the name of the flow you intend to add in the box where it says Flow. Let s first add the steel wire. If you type in steel wire and hit enter, one of three outcomes will occur. The first outcome that can happen is that GaBi recognizes the flow automatically due to there being only one flow with that name. This is the case with Steel wire and the information regarding the flow should automatically be shown now. At this point, you should enter the amount of material the flow will be using. After doing some research, we have determined that the amount of steel wire needed to create a paperclip is 0.35 g, which in kg is kg. Under the amount column, next to the steel wire, please enter and hit enter. Under the small tracked flows column, click the box until an X appears, signifying that it is a tracked flow. This process also requires power to bend the paperclip. In a new line, please type in power and hit enter. Since GaBi has more than one flow with power in the name, the second outcome occurs and a search window like the one in Figure

44 Using an LCA Software to Create Models Figure 27: Flow Search Window Since we are looking for electricity for this process, please select the flow called Power with the object group called Electric Power then hit Accept. This will place the flow into the process with all of the necessary information. As with the amount of steel wire needed, we have done research and estimate the amount of power needed to be kwh. You will notice that the unit listed next to power is MJ, not kwh. The nice thing about flows is that they have conversion factors already in place. If you select the unit, MJ, you will be able to select a different unit from a drop-down list of available units for the flow. In this case, we have information in kwh so please select kwh from the list and enter into the amount and hit enter. After an amount has been entered, you can switch the units again to see how much power is needed, say in MJ, which will show that kwh is equivalent to MJ. Be sure to make the power a tracked flow as well. For the bending process, we have both inputs entered into the process, both the steel wire and power. We now need to add the steel paperclip as an output from the system. Under outputs, please enter steel paperclip into the Flow box and hit enter. Since GaBi doesn t have that flow stored, the third outcome will occur, and a window will pop up asking you what to do. Figure 28: No Flow Found Window 44

45 Using an LCA Software to Create Models If you are sure the flow exists, you can select Search and attempt to search for the flow to find it. If the flow doesn t exist, and you have the necessary information, you can select Create New Object. The next section will take you through how to create a new flow Create new Flows Flows are usually created from one of two scenarios. The first scenario, as described above, is when a flow is being added to a process and it doesn t exist, and therefore needs to be created. The second is just like creating new plans or processes. Under the Object hierarchy, select Flows, then click on the blank page in the top left. Both of these scenarios will bring up a new window, allowing you to create your new flow. This window allows you to select the type of flow it will be. For example, the natural gas flow we looked at earlier was under Resources, Energy Resources, Non renewable energy resources, and finally Natural gas. The flow we are interested in creating is our product, the steel paperclip, so it makes sense to locate the flow under Valuable substances, Systems, Parts, and finally Metal parts. Once selecting Metal parts, please hit okay. This will bring up a new window where the flow is actually created. At the top of the window, they name of the flow should already be entered based upon what you entered into the process. The location where the flow is placed will determine the flow type. Flows that are saved to the resources folder are automatically inputs where as emissions are automatically outputs. Flows that are within the system can be categorized as none since they don t enter or leave the system, only flow through it. Be sure to select the correct flow type though as this is important when the balance calculations are performed. The default type for this flow is none and we will leave it as such. The other field that is necessary for creating a flow is the reference quantity. The standard is mass and this is what GaBi automatically assumes, with the units of kg. If quantities are added to the flow at the bottom of the window, they must be added in terms of 1 kg of the flow material, in this case, steel paperclips. The most important field in the flow window is the Quantity field at the bottom of the window. This is where you place all of the inputs and outputs that occur from this flow. The functional unit of our LCA study is in terms of number of paperclips and not mass so we need to make sure the flow can be shown in the number of paperclips. To do this, doubleclick on the empty quantity box, type number of pieces, and hit enter. To define the conversion factor, you need to type in the information to the right of the name. In this case, we know that one paperclip is kg so we enter this number under the 1 [Quantity] = * kg box. You will notice that GaBi automatically updates the field labelled 1 kg = *. This should shows you that 1 kg of paperclips is the same as paperclips. 45

46 Using an LCA Software to Create Models Once finished, the flow should look like the flow in Figure 29. If so, click the save button across the top and close the window. Figure 29: New Flow Window After closing the window, it should bring back the Paperclip Bending process. The steel paperclip flow should now be listed under outputs. Make sure the amount of the flow is entered by either entering the mass of the paperclip ( kg) or by changing the Quantity to number of pieces and entering 1, since the functional unit of the process is one paperclip. After being sure to make the flow a tracked flow, you should save the process and close the window. At this point, be sure to drag the new bending process into your plan. Once you have finished creating the bending process, you need to define the reference process for the plan. In our study, we are looking at creating paperclips so the reference process should be the process in which we create our product, in this case, the paperclip bending process. To set this process as the reference process, double-click on the process. In the top left of the window is a check-box labelled Fixed along with a scaling factor. Check the Fixed box to make this process the reference process. For our LCA study, we want the functional unit to be 1000 paperclips so you would set the scaling factor to be Once you are finished with this, the process should look like the window in Figure 30. If so, please click ok to close the window. Setting this process to be Fixed will now cause all of the other processes connected to it to scale according to your fixed process and the functional unit set for that process. 46

47 Using an LCA Software to Create Models In every plan, one and only one process has to be fixed. If there isn t a fixed process, or more than one fixed process in a linked chain, an error message will appear and you should go back and make sure there is only one fixed process. Figure 30: Updated Process Window Figure 31: Updated Plan View At this point in the walk-through, your plan should look like Figure 31. One thing to note about the plan view is that you can arrange the processes in any way you wish that makes it easiest to understand for you. 47

48 Using an LCA Software to Create Models 3.8 Finishing the Example Transportation To make the model more detailed, we are going to add a transportation aspect to it. We are going to assume the steel wire is being transported to the facility where the bending process is going to take place. A good assumption for the truck in this case is a 20t truck. Please locate this process now and add it to the plan between the bending process and the steel wire. The process we will be using is the Truck 20-26t total cap./17,3 payload / Euro 3 (local). Be sure to resize the process so that the whole title of the process can be read in the plan view. This is as easy as dragging one of the resize points along the border of the process. Most transportation processes will have an input and output as cargo. This is a generic name and any tracked flow can be connected to it. In this case, we are transporting the steel wire. If you link the two processes now, GaBi will not know which output to match with which input. Be sure to select steel wire as the output and cargo as the input, naming the flow steel wire. When connecting the truck process to the paperclip bending process, it should automatically connect since the cargo has been renamed to steel wire, which matches the input flow of the paperclip bending process Use Phase Most of the products that will be modelled for an LCA will have a use phase depending on the scope of the project. Since GaBi doesn t contain processes for the use phase, you will almost always need to create a new process for this. Let s do that now. Like before, create a new process from the GaBi DB Manager. Name this process Use Phase Steel Paperclip. Again, the region is optional but we will be using DE for Germany, the source is optional, and the type is a basic process so select b from the dropdown menu. Since a paperclip doesn t use any power or create any emissions, there will only be the paperclip as an input and steel scrap as an output. If you can, try to add them yourself. Under the inputs, enter steel paperclip and hit enter. Since we already created the flow earlier, it should automatically be entered. If not, select the correct flow from the search list. You can either enter the mass as kg or change the Quantity to Number of pieces and enter 1 and be sure to make this a tracked flow. After the paperclip is used, we are going to assume it is going to be steel scrap. Enter this into the output now and hit enter. GaBi has multiple flows with steel scrap in the title but we want the Steel scrap (St) flow so select this and hit accept. The amount of steel scrap is the same as the paperclip so enter kg. By nature, this flow is a waste flow so click on the box under the tracked flow column until the star (*) appears. Save this process and close the window. Once you have created the process, find it by either searching or locating it under the processes folder of the Object hierarchy and drag it into your plan End-of-Life Along with the use phase, most LCA studies will have an end-of-life (EoL) phase, again, depending on the scope of the study. As mentioned earlier in the handbook, you can 48

49 Using an LCA Software to Create Models have plans within plans. We are going to go through an example of that now, creating an EoL plan. The quickest way to create a new plan now is to click the blank page icon in the top left of the plan you are currently on. Name the plan End of Life Paperclip. Usually, you would add multiple waste routes the product could take, including landfill, recycling, or incineration, but since this is a beginner s model, we are only going to include the recycling portion of the EoL model. To find the process we are going to use, search the processes for steel, and select the process belonging to the object group Material Recovery called steel billet (electric furnace). Drag that process into the plan. As mentioned before, every plan needs to have one fixed process so be sure to make this single process fixed to 1 now. Save the plan and close it. You may have noticed that there was a red dot in the corner of the process that was never connected to another process in the EoL plan. In cases like these, you can add the unconnected plan to another plan and connect it to other plans or processes just as if it were a process. At this point, you should add the EoL plan to the Life Cycle Steel Paperclip plan by dragging it and dropping. Since the output of the End-of-Life plan is steel billet, we can connect this back to the steel wire plan, creating a circular material flow. Do this now. Make sure you are connecting the output side (brown bar) of one process to the input side (red bar) of another one Final Touches At this point, you know everything you need to know to finish creating the plan. Try to finish creating the plan now. A tip to get started is to find all of the unconnected tracked flows and fill them with the correct process. If you need help, the following list is what should be done. Find the DE: Power grid mix process and add it to the plan near the Paperclip bending process. This is the German power grid mix and should be used for consistency with videos so the correct numbers are shown. For future plans, any power grid mix may be used. Also, be sure to connect the two processes. The truck process requires diesel so we should find this now and add it to the plan. We will be using the German (DE) process Diesel at refinery. Be sure to place it near the truck process and connect them. Connect the rest of the processes. o Paperclip bending to use phase o Use phase to end-of-life Congratulations, you have now completed modelling the life cycle of a steel paperclip! There are some things you can do to adjust the visual appearance of the plan. You can move the arrows of the flows around to make the plan flow better visually. Double-clicking on the flow will bring up the properties of the flow, allowing you to change color. This can be helpful to show the material flows as one color, power as another, and so on. We have discussed comments before but we should add one now to get practice. Click on the comment button located at the top of the plan. You can choose the background 49

50 Using an LCA Software to Create Models and text colors to your liking and enter the text: This model contains non-representative assumptions. After hitting ok, you will now be able to move and resize the comment box to your liking. After all of this, your model should look like the plan pictured in Figure 32: Figure 32: Final Plan View Keep in mind that your plan may visually look different based on your preferences for location and colors or the processes and flows. The general flow should be the same though. You have just learned how to create models using GaBi. In the next chapter, we will show you what you can do with these models once they are complete. 3.9 Balances and Outputs At this point, you should be comfortable creating a model using LCA software. Creating a model is only the background to creating a true LCA. The Life Cycle Inventory (LCI), Life Cycle Inventory Analysis (LCIA), and interpretation of the outputs are what make an LCA useful. 50

51 Using an LCA Software to Create Models In this section, we will learn how to create balances within GaBi which are the collections of data from the model and include all of the LCI and LCIA results. We will learn how to read and understand them, along with what they can tell us Create a New Balance To create a balance, it is as easy as having the plan open to which you want to create a balance, and then clicking the balance button at the top of the plan indicated by two crossed purple arrows. This will bring up the windown in Figure 33: Figure 33: Balance Window In this window, we can choose how we want the LCI and LCIA results to be viewed. At the top of the balance window, you can name the balance if you wish to save it to refer to later. The default is going to be the name of the plan it was created from. To save it, you can just click on the save icon in the top left of the window. This will save the balance into the Balances folder under the GaBi Object hierarchy. One thing to note: if you change your plan after saving a balance, the balance will not automatically update. You will need to create a new balance and save that one. There are three tabs across the top to change between the different methods of calculation. LCA is used most commonly and stands for Life Cycle Assessment. LCC is Life Cycle Costing and is used if you have entered cost data into the different processes. LCWT is Life Cycle Working Time and is used if you have entered this data into the processes. Since we have not entered the last two types of data into our processes, we can ignore these tabs for this example. 51

52 Using an LCA Software to Create Models Inputs and Outputs Right now, the balance shown has the inputs and outputs separated. This is the default setting so you can be sure to see them separately. If you would like to see net results, you can uncheck the box labelled separate IO tables. If there are flows in both the input and output sides, they will be merged. Uncheck the box now so we can see the net results. Next to this checkbox is another one labelled Just elementary flows and when checked, will not include the non-elementary flows valuable substances, Production residues in life cycle, and Deposited goods. Here you see the significance of specifying flows as either elementary or non-elementary. In order to view the LCI of the paperclip product system, we need to deselect the only elementary flows checkbox and select the separate IO tables one. Do this now. Now we see all of the substances that enter or leave the system. Go back now and select the Just elementary flows. In the table it shows you the total values for each of the different flow categories. Each category shows the flows that enter the system from nature and exit the system back to nature. If a row is bold, it means it is a category/subcategory and contains either more subcategories or a group of flows. By double-clicking on these bolded rows, you can expand them. For this model, we have used electricity so there will be some crude oil consumed in the process. Let s take a look now to see how much for 1000 paperclips. Since the crude oil is a non-renewable consumed energy resource, it will be on the input side. Try to locate the bold row labelled Crude oil (resource). It is located under the input side, Resources Energy resources Non renewable energy resources. Here you will see the aggregated amount of crude oil that is consumed for the system. Double-clicking on the row will open it up to the individual flows showing what country the oil would come from. Figure 34: Input Table 52

53 Using an LCA Software to Create Models Process Results At this point, the results are for the whole paperclip system. If we want to see where the materials are being used and emissions released, we can expand the system as well. Just like with the flows, you can double-click on the Life Cycle Steel Paperclip column header to open up the system and see the contribution from each of the processes and subplans within the overall model. The numbers you are looking at right now are in terms of kg of each listed flow. If you wanted to see the numbers in a different quantity, you would choose it from the quantity drop down menu. Let s look at a quantity that tells us more about the environmental impact of the system. Click on the drop down menu and scroll up and choose CML 2001 Dec 07 Global Warming Potential (GWP 100 years) [kg CO2-Equiv]. As you can see, the numbers in the balance changed and now displays the kg CO2-equivalents for the plan. Notice that the resources category on the input side and the emissions to air on the output side are the only two categories with numbers. Intuitively, this should make sense Quantity View Another way to view the results in the balance is in the Quantity view, turned on by checking the box at the top of the window. When this box is checked, the inputs and outputs are no longer in terms of flows, but in terms of the quantities that could be selected from the drop down menu. This allows you to see the inputs and outputs in terms of the CML or TRACI impact categories that are widely used in the LCA community. Please check the box now. At first, you will notice that there are no numbers on the screen. This is because you cannot aggregate the different quantities. If you open one of the three categories for the three types of quantities, you will then see the results based on quantity. The environmental quantities category contains all of the impact categories that are used for LCAs. Under technical quantities you find energy and mass, along with other values. If economic data was entered into the processes, the results would show up in the economic quantities. Now uncheck Quantity view and separate IO tables to get back to the flow view with the aggregated table with the global warming potential quantity still selected. You will notice that there is a negative value under the resources category. This is because there were more input flows for this category than outputs. This makes sense from our definition of flows earlier where we described resource flows as inputs and emissions flows as outputs. This should always make the resources category a negative value, and emissions a positive one. 53

54 Using an LCA Software to Create Models Weak Point Analysis One of the largest uses for the balances is to locate where in the system are the highest emissions or most resources taken in. GaBi has a nice feature incorporated into it called the Weak Point Analysis Tool. When the Weak Point Analysis button is selected, some of the values are highlighted in red, as shown in Figure 35. These are the weak points in the life cycle that correspond to more than 10% of the total sum in that specific category/quantity. Grey values are those that contribute minimally to the total result. Some rows/columns completely disappear since they have no contribution at all. The thresholds for the Weak Point Analysis can be set in the options of the balance window. Figure 35: Weak Point Analysis Relative Contribution Let s search now for the most contributing flows in the categories resources and emissions to air by double clicking on the categories. After opening emissions to air and then inorganic emissions to air, you will notice that carbon dioxide is the leading contributor to the global warming potential when creating a steel paperclip. In the top right corner of the window, you should see a box where you can choose between showing the results in terms of absolute values or relative contribution. Change the view to relative contribution now. It is obvious now that the carbon dioxide emissions contribute most to the global warming potential. For future reference, you can right click on a column and define which process is to be considered the 100% mark. This becomes useful when comparing different products or processes, which we aren t doing here Creating a Graph For our example, we only want to graph the results of the carbon dioxide emissions so be sure that the balance is in terms of absolute values in separate IO tables. Find and select the carbon dioxide row under the outputs. In order to create a graph, you should have the 54

55 Using an LCA Software to Create Models intended row selected then click on the Diagram button at the right of the outputs header. This will bring up a window like the one in Figure 36: As you can see, there are many options you can choose from to create a graphic output of the results. Once you have created the graphic you like, you can hit the copy button in the top right and paste it into a document for a report. Figure 36: Results Graph Exporting to Excel Many users will use excel alongside GaBi to compare results and to create different graphs. GaBi makes it easy to export its data into excel. The best way to do it is to select the cells you want to export into excel, right-click and hit copy, then paste it into excel. If you have excel and wish to follow along, copy the whole carbon dioxide row we just created a diagram for and paste it into excel. You will notice that not only will the selected cells get copied over, but the quantity name, flow name, and the processes will as well. This is convenient so you know where the data is coming from. If you followed along, you will see the the excel window in Figure 37: 55

56 Using an LCA Software to Create Models Figure 37: Results in Excel Comparing Models Not only can balances be used to compare the results of different processes within a plan, but it can be used to compare whole plans. You may have noticed that we have included other paperclip plans in the database provided. To compare two or more plans within a balance view, you should select the plans you wish to compare, and then click the Calculate Balance button. The two plans will now show up as separate columns just as if they were processes within the same plan. You can compare them using the relative comparison view, or use any of the other options within the balance view. This concludes the walkthrough tutorial for creating a model for the Life Cycle of a Steel Paperclip. Look around GaBi and try to create a plan of your own. If you have any further questions on any of the topics either covered in this handbook or that you many have found while exploring GaBi, please use any of the resources found on the right side of the GaBi Start Page. Here you will see a link for a GaBi 4 manual, contact information for PE International, as well as links to learn more about LCA in general. We hope you have enjoyed learning about GaBi and LCA! 56

57 Bibliography 4 Bibliography GABI 2003 GUINÉE ET AL GaBi 4: Software und Datenbank zur Ganzheitlichen Bilanzierung. IKP, Universität Stuttgart und PE Europe GmbH, Leinfelden- Echterdingen, April LCA impact assessment of toxic releases; Generic modelling of fate, exposure and effect for ecosystems and human beings. (no. 1996/21) Centre of Environmental Science (CML) Leiden and National Institute of Public Health and Environmental Protection (RIVM), Bilthoven, May GUINÈE ET AL GUINÉE ET AL IKP 2003 Guinée, J. et. al. Handbook on Life Cycle Assessment - Operational Guide to the ISO Standards. Centre of Environmental Science, Leiden University (CML); The Netherlands, Handbook on Life Cycle Assessment: An operational Guide to the ISO Standards; Dordrecht: Kluvver Academic Publsihers, Institut für Kunststoffprüfung und Kunststoffkunde der Universität Stuttgart, Abteilung Ganzheitliche Bilanzierung, 2003 ISO : 1997 ISO Environmental Management Life Cycle Assessment Principles and Framework, 1997 ISO : 1998 ISO Environmental Management Life Cycle Assessment Goal and Scope Definition and Inventory Analysis ISO : 2000 ISO Environmental Management Life Cycle Assessment Life Cycle Impact Assessment, 2000 ISO : 2000 ISO Environmental Management Life Cycle Assessment Life Cycle Interpretation, 2000 KREISSIG & KÜMMEL 1999 Kreißig, J. und J. Kümmel (1999): Baustoff-Ökobilanzen. Wirkungsabschätzung und Auswertung in der Steine-Erden-Industrie. Hrsg. Bundesverband Baustoffe Steine + Erden e.v. 57

58 Appendix A Appendix A Description of result parameters Appendix A 1 Primary energy consumption Primary energy demand is often difficult to determine due to the various types of energy source. Primary energy demand is the quantity of energy directly withdrawn from the hydrosphere, atmosphere or geosphere or energy source without any anthropogenic change. For fossil fuels and uranium, this would be the amount of resource withdrawn expressed in its energy equivalent (i.e. the energy content of the raw material). For renewable resources, the energy-characterised amount of biomass consumed would be described. For hydropower, it would be based on the amount of energy that is gained from the change in the potential energy of the water (i.e. from the height difference). As aggregated values, the following primary energies are designated: The total Primary energy consumption non renewable, given in MJ, essentially characterises the gain from the energy sources natural gas, crude oil, lignite, coal and uranium. Natural gas and crude oil will be used both for energy production and as material constituents e.g. in plastics. Coal will primarily be used for energy production. Uranium will only be used for electricity production in nuclear power stations. The total Primary energy consumption renewable, given in MJ, is generally accounted seperately and comprises hydropower, wind power, solar energy and biomass. It is important that the end energy (e.g. 1 kwh of electricity) and the primary energy used are not miscalculated with each other; otherwise the efficiency for production or supply of the end energy will not be accounted for. The energy content of the manufactured products will be considered as feedstock energy content. It will be characterised by the net calorific value of the product. It represents the still usable energy content. Appendix A 2 Waste categories There are various different qualities of waste. Waste is according to e.g. German and European waste directives. From the balancing point of view, it makes sense to divide waste into three categories. The categories overburden/tailings, industrial waste for municipal disposal and hazardous waste will be used. Overburden / tailings in kg: This category is made up of the layer which has to be removed in order to get access to raw material extraction, ash and other raw material extraction conditional materials for disposal. Also included in this category are tailings such as inert rock, slag, red mud etc. Industrial waste for municipal disposal in kg: This term contains the aggregated values of industrial waste for municipal waste acording to 3. AbfVwV TA SiedlABf. Hazardous waste in kg: In this category, materials that will be treated in a hazardous waste incinerator or hazardous waste landfill, such as painting sludges, galvanic sludges, filter dusts or other solid or liquid hazardous waste and radioactive waste from the operation of nuclear power plants and fuel rod production. 58

59 Appendix A Appendix A 3 Global Warming Potential (GWP) The mechanism of the greenhouse effect can be observed on a small scale, as the name suggests, in a greenhouse. These effects are also occurring on a global scale. The occuring short-wave radiation from the sun comes into contact with the earth s surface and is partly absorbed (leading to direct warming) and partly reflected as infrared radiation. The reflected part is absorbed by so-called greenhouse gases in the troposphere and is reradiated in all directions, including back to earth. This results in a warming effect at the earth s surface. In addition to the natural mechanism, the greenhouse effect is enhanced by human activites. Greenhouse gases that are considered to be caused, or increased, anthropogenically are, for example, carbon dioxide, methane and CFCs. Figure A 1 shows the main processes of the anthropogenic greenhouse effect. An analysis of the greenhouse effect should consider the possible long term global effects. The global warming potential is calculated in carbon dioxide equivalents (CO 2 -Eq.). This means that the greenhouse potential of an emission is given in relation to CO 2 Since the residence time of the gases in the atmosphere is incorporated into the calculation, a time range for the assessment must also be specified. A period of 100 UV - radiation Infrared radiation Absorption Reflection CFCs CO 2 CH 4 years is customary. Figure A 1: Greenhouse effect (KREISSIG & KÜMMEL 1999) Trace gases in the atmosphere Appendix A 4 Acidification Potential (AP) The acidification of soils and waters occurs predominantly through the transformation of air pollutants into acids. This leads to a decrease in the ph-value of rainwater and fog from 5.6 to 4 and below. Sulphur dioxide and nitrogen oxide and their respective acids (H 2 SO 4 und HNO 3 ) produce relevant contributions. This damages ecosystems, whereby forest dieback is the most well-known impact. Acidification has direct and indirect damaging effects (such as nutrients being washed out of soils or an increased solubility of metals into soils). But even buildings and building materials can be damaged. Examples include metals and natural stones which are corroded or disintegrated at an increased rate. When analysing acidification, it should be considered that although it is a global problem, the regional effects of acidification can vary. Figure A 2 displays the primary impact pathways of acidification. 59

60 Appendix A The acidification potential is given in sulphur dioxide equivalents (SO 2 -Eq.). The acidification potential is described as the ability of certain substances to build and release H + - ions. Certain emissions can also be considered to have an acidification potential, if the given S-, N- and halogen atoms are set in proportion to the molecular mass of the emission. The reference substance is sulpher dioxide. Figure A 2: H 2 SO 44 HNO 3 SO 2 NO X Acidification Potential (KREISSIG & KÜMMEL 1999) Appendix A 5 Eutrophication Potential (EP) Eutrophication is the enrichment of nutrients in a certain place. Eutrophication can be aquatic or terrestrial. Air pollutants, waste water and fertilization in agriculture all contribute to eutrophication. The result in water is an accelerated algae growth, which in turn, prevents sunlight from reaching the lower depths. This leads to a decrease in photosynthesis and less oxygen production. In addition, oxygen is needed for the decomposition of dead algae. Both effects cause a decreased oxygen concentration in the water, which can eventually lead to fish dying and to anaerobic decomposition (decomposition without the presence of oxygen). Hydrogen sulphide and methane are thereby produced. This can lead, among others, to the destruction of the eco-system. On eutrophicated soils, an increased susceptibility of plants to diseases and pests is often observed, as is a degradation of plant stability. If the nutrification level exceeds the amounts of nitrogen necessary for a maximum harvest, it can lead to an enrichment of nitrate. This can cause, by means of leaching, increased nitrate content in groundwater. Nitrate also ends up in drinking water. Nitrate at low levels is harmless from a toxicological point of view. However, nitrite, a reaction product of nitrate, is toxic to humans. The causes of eutrophication are displayed in Figure A 3. The eutrophication potential is calculated in phosphate equivalents (PO 4 -Eq). As with acidification potential, it s important to remember that the effects of eutrophication potential differ regionally. NOX Air pollution Figure A 3: N2O NH3 Waste water PO4-3 Eutrophication Potential (KREISSIG & KÜMMEL 1999) Fertilisation - NO3 NH4 + 60

61 Appendix A Appendix A 6 Photochemical Ozone Creation Potential (POCP) Despite playing a protective role in the stratosphere, at ground-level ozone is classified as a damaging trace gas. Photochemical ozone production in the troposphere, also known as summer smog, is suspected to damage vegetation and material. High concentrations of ozone are toxic to humans. Radiation from the sun and the presence of nitrogen oxides and hydrocarbons incur complex chemical reactions, producing aggressive reaction products, one of which is ozone. Nitrogen oxides alone do not cause high ozone concentration levels. Hydrocarbon emissions occur from incomplete combustion, in conjunction with petrol (storage, turnover, refuelling etc.) or from solvents. High concentrations of ozone arise when the temperature is high, humidity is low, when air is relatively static and when there are high concentrations of hydrocarbons. Today it is assumed that the existance of NO and CO reduces the accumulated ozone to NO 2, CO 2 and O 2. This means, that high concentrations of ozone do not often occur near hydrocarbon emission sources. Higher ozone concentrations more commonly arise in areas of clean air, such as forests, where there is less NO and CO (Error! Reference source not found.). In Life Cycle Assessments, photochemical ozone creation potential (POCP) is referred to in ethyleneequivalents (C 2 H 4 -Äq.). When analyzing, it s important to remember that the actual ozone concentration is strongly influenced by the weather and by the characterristics of the local conditions. Hydrocarbons Nitrogen oxides Ozone Dry and warm climate Hydrocarbons Nitrogen oxides Figure A 4: Photochemical Ozone Creation Potential (KREISSIG & KÜMMEL 1999) Appendix A 7 Ozone Depletion Potential (ODP) Ozone is created in the stratosphere by the disassociation of oxygen atoms that are exposed to short-wave UV-light. This leads to the formation of the so-called ozone layer in the stratosphere (15-50 km high). About 10 % of this ozone reaches the troposphere through mixing processes. In spite of its minimal concentration, the ozone layer is essential for life on earth. Ozone absorbs the short-wave UV-radiation and releases it in longer wavelengths. As a result, only a small part of the UV-radiation reaches the earth. Anthropogenic emissions deplete ozone. This is well-known from reports on the hole in the ozone layer. The hole is currently confined to the region above Antarctica, however another ozone depletion can be identified, albeit not to the same extent, over the midlatitudes (e.g. Europe). The substances which have a depleting effect on the ozone can essentially be divided into two groups; the fluorine-chlorine-hydrocarbons (CFCs) and the nitrogen oxides (NOX). Error! Reference source not found. depicts the procedure of ozone depletion. 61

62 Appendix A One effect of ozone depletion is the warming of the earth's surface. The sensitivity of humans, animals and plants to UV-B and UV-A radiation is of particular importance. Possible effects are changes in growth or a decrease in harvest crops (disruption of photosynthesis), indications of tumors (skin cancer and eye diseases) and decrease of sea plankton, which would strongly affect the food chain. In calculating the ozone depletion potential, the anthropogenically released halogenated hydrocarbons, which can destroy many ozone molecules, are recorded first. The so-called Ozone Depletion Potential (ODP) results from the calculation of the potential of different ozone relevant substances. This is done by calculating, first of all, a scenario for a fixed quantity of emissions of a CFC reference (CFC 11). This results in an equilibrium state of total ozone reduction. The same scenario is considered for each substance under study whereby CFC 11 is replaced by the quantity of the substance. This leads to the ozone depletion potential for each respective substance, which is given in CFC 11 equivalents. An evaluation of the ozone depletion potential should take into consideration the long term, global and partly irreversible effects. UV - radiation Stratosphere km Absorption Absorption CFCs Nitrogen oxide Figure A 5: Ozone Depletion Potential (KREISSIG & KÜMMEL 1999) Appendix A 8 Human and eco-toxicity The method for the impact assessment of toxicity potential is still, in part, in the development stage. The Human Toxicity Potential (HTP) assessment aims to estimate the negative impact of, for example, a process on humans (Error! Reference source not found.). The Eco-Toxicity potential aims to outline the damaging effects on an ecosystem. This is differentiated into Terrestrial Eco-Toxicity Potential (TETP, Error! Reference source not found.) and Aquatic Eco-Toxicity Potential (AETP, Error! Reference source not found.) In general, one distinguishes acute, sub-acute/sub-chronic and chronic toxicity, defined by the duration and frequency of the impact. The toxicity of a substance is based on several parameters. Within the scope of life cycle analysis, these effects will not be mapped out to such a detailed level. Therefore, the potential toxcity of a substance based on its chemical composition, physical properties, point source of emission and its behaviour and whereabouts, is characterised according to its release to the environment. Harmful substances can spread to the atmosphere, into waterbodies or into the soil. Therefore, potential contributors to important toxic loads are ascertained. Characterisation factors are calculated through the Centre of Environmental Science (CML), Leiden University, and the National Institute of Public Health and Environmental Protection (RIVM), Bilthoven, based on the software USES 1.0 (GUINÉE ET AL. 1996). The model, LCA-World, which underlies the calculation, is based on the assumptions of 62

63 Appendix A a slight exchange of rainwater and air (western Europe), long residence times of substances, moderate wind and slight transposition over the system boundaries. 63

64 Appendix A The surface of the model is divided into 3% surface water, 60% natural soil, 27% agricultural soil and 10% industrial soil. 25% of the rainwater is infiltrated into the soil. The potential toxicities (human, aquatic and terrestrial ecosystems) are generated from a proportion based on the reference substance 1,4- Dichlorbenzol (C 6 H 4 Cl 2 ) in the air reference section. The unit is kg 1,4- Dichlorbenzol-Equiv. (kg DCB-Äq.) per kg emission (GUINÉE ET AL. 2002). The identification of the toxicity potential is afflicated with uncertainties because the impacts of the individual substances are extremely dependent on exposure times and various potential effects are aggregated. The model is therefore based on a comparison of effect and exposure assessment. It calculates the concentration in the environment via the amount of emission, a distribution model and the risk characterisation via an input sensitive module. Degradation and transport in other environmental compartements are not represented. Toxicity potential can be calculated with toxilogical threshold values, based on a contiuous exposure to the substance. This leads to a division of the toxicity into the groups mentioned above (HTP, AETP, TETP) for which, based on the location of the emission source (air, water, soil), three values are calculated. Consequently, there is a matrix for toxic substances with rows of the various toxicities that have impacts on both humans and aquatic and terrestrial ecosystems, and columns of the extent of the toxic potential, considering the different emission locations. Halogenorganic compounds Heavy metals DCB PCB PAH Air Food Products Figure A 6: Human Toxicity Potential (IKP 2003) Halogenorganic compounds Heavy metals DCB PAH PCB Biosphere (Terrestrial ecosystem) Figure A 7: Terrestrial Eco-Toxicity Potential (IKP 2003) Halogenorganic compounds Heavy metals PCB DCB PAH Biosphere (Aquatic ecosystem) Figure A 8: Aquatic Eco-Toxicity Potential (IKP 2003) 64

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