Confronting Uncertainty in Life Cycle Assessment Used for Decision Support

The aim of this article is to help confront uncertainty in life cycle assessments (LCAs) used for decision support. LCAs offer a quantitative approach to assess environmental effects of products, technologies, and services and are conducted by an LCA practitioner or analyst (AN) to support the decision maker (DM) in making the best possible choice for the environment. At present, some DMs do not trust the LCA to be a reliable decision‐support tool—often because DMs consider the uncertainty of an LCA to be too large. The standard evaluation of uncertainty in LCAs is an ex‐post approach that can be described as a variance simulation based on individual data points used in an LCA. This article develops and proposes a taxonomy for LCAs based on extensive research in the LCA, management, and economic literature. This taxonomy can be used ex ante to support planning and communication between an AN and DM regarding which type of LCA study to employ for the decision context at hand. This taxonomy enables the derivation of an LCA classification matrix to clearly identify and communicate the type of a given LCA. By relating the LCA classification matrix to statistical principles, we can also rank the different types of LCA on an expected inherent uncertainty scale that can be used to confront and address potential uncertainty. However, this article does not attempt to offer a quantitative approach for assessing uncertainty in LCAs used for decision support.     

Life‐cycle and cost of goods assessment of fed‐batch and perfusion‐based manufacturing processes for mAbs

Life‐cycle assessment (LCA) is an environmental assessment tool that quantifies the environmental impact associated with a product or a process (e.g., water consumption, energy requirements, and solid waste generation). While LCA is a standard approach in many commercial industries, its application has not been exploited widely in the bioprocessing sector. To contribute toward the design of more cost‐efficient, robust and environmentally‐friendly manufacturing process for monoclonal antibodies (mAbs), a framework consisting of an LCA and economic analysis combined with a sensitivity analysis of manufacturing process parameters and a production scale‐up study is presented. The efficiency of the framework is demonstrated using a comparative study of the two most commonly used upstream configurations for mAb manufacture, namely fed‐batch (FB) and perfusion‐based processes. Results obtained by the framework are presented using a range of visualization tools, and indicate that a standard perfusion process (with a pooling duration of 4 days) has similar cost of goods than a FB process but a larger environmental footprint because it consumed 35% more water, demanded 17% more energy, and emitted 17% more CO₂ than the FB process. Water consumption was the most important impact category, especially when scaling‐up the processes, as energy was required to produce process water and water‐for‐injection, while CO₂ was emitted from energy generation. The sensitivity analysis revealed that the perfusion process can be made more environmentally‐friendly than the FB process if the pooling duration is extended to 8 days. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1324–1335, 2016     

Using GaBi 3 to perform life cycle assessment and life cycle engineering

The growing availability of software tools has increased the speed of generating LCA studies. Databases and visual tools for constructing material balance modules greatly facilitate the process of analyzing the environmental aspects of product systems over their life cycle. A robust software tool, containing a large LCI dataset and functions for performing LCIA and sensitivity analysis will allow companies and LCA practitioners to conduct systems analyses efficiently and reliably. This paper discusses how the GaBi 3 software tool can be used to perform LCA and Life Cycle Engineering (LCE), a methodology that combines life cycle economic, environmental, and technology assessment. The paper highlights important attributes of LCA software tools, including high quality, well-documented data, transparency in modeling, and data analysis functionality. An example of a regional power grid mix model is used to illustrate the versatility of GaBi 3.     

Application typologies for life cycle assessment

Different lists of application areas for life cycle assessment are reviewed together with some suggestions for a typology of these application areas. It is concluded that the scope of a life cycle assessment is determined by the area of validity of the decision with respect to time, space, and interest groups affected. On this basis, six application areas are distinguished. It is further concluded that the application area has limited influence on the inventory analysis and impact assessment phases, although these may be influenced significantly by the decision-maker and the complexity of the trade-offs between the involved environmental impacts. The reporting format for a life cycle assessment depends on the socio-economic importance of the decision, the intended audience, and the time available for decision making.     

Applying voting rules to panel-based decision making in LCA

Background, aim, and scope  Cross-category weighting is one possible way to facilitate internal decision making when dealing with ambiguous impact assessment results, with simple additive weighting being a commonly used method. Yet, the question as to whether the methods applied today can, in fact, identify the most “environmentally friendly” alternative from a group perspective remains unanswered. The aim of this paper is to propose a new method for group decision making that ensures the effective identification of the most preferable alternative. Materials and methods  Common approaches to deduce a single set of weighting factors for application in a group decision situation (e.g., arithmetic mean, consensus) are discussed based on simple mathematics, empirical data, and thought experiments. After proposing an extended definition for “effectiveness” in group decision making, the paper recommends the use of social choice theory whose main focus is to identify the most preferable alternative based on individuals’ rankings of alternatives. The procedure is further supplemented by a Monte Carlo analysis to facilitate the assessment of the result’s robustness. Results  The general feasibility of the method is demonstrated. It generates a complete ranking of alternatives, which does not contain cardinal single scores. In terms of effectiveness, the mathematical structure of the procedure ensures the eligibility for compromise of the group decision proposal. The sensitivity analysis supports the decision makers in understanding the robustness of the proposed group ranking. Discussion  The method is based upon an extended definition of effectiveness which acknowledges the eligibility for compromise as the core requirement in group decision contexts. It is shown that multi-attribute decision-making (MADM) methods in use in life cycle assessment (LCA) today do not necessarily meet this requirement because of their mathematical structure. Further research should focus on empirical proof that the generated group results are indeed more eligible for compromise than results generated by current methods that utilize an averaged group weighting set. This is closely related to the question considering under which mathematical constraints it is even possible to generate an essentially different result. Conclusions  The paper describes a new multi-attribute group decision support system (MGDSS) for the identification of the most preferable alternative(s) for use in panel-based LCA studies. The main novelty is that it refrains from deducing a single set of weighting factors which is supposed to represent the panel as a whole. Instead, it applies voting rules that stem from social choice theory. Because of its mathematical structure, the procedure is deemed superior to common approaches in terms of its effectiveness. Recommendations and perspectives  The described method may be recommended for use in internal, panel-based LCA studies. In addition, the basic approach of the method—the combination of MADM methods with social choice theory—can be recommended for use in all those situations where multi-attribute decisions are to be made in a group context.     

Incorporating costs in LCA

The goal of LCA is to identify the environmental impacts resulting from a product, process, or activity. While LCA is useful for evaluating environmental attributes, it stops short of providing information that business managers routinely utilize for decision-making — i.e., dollars. Thus, decisions regarding the processes used for manufacturing products and the materials comprising those products can be enhanced by weaving cost and environmental information into the decision-making process. Various approaches have been used during the past decade to supplement environmental information with cost information. One of these tools is environmental accounting, the identification, analysis, reporting, and use of environmental information, including environmental cost data. Environmental cost accounting provides information necessary for identifying the true costs of products and processes and for evaluating opportunities to minimize those costs. As demonstrated through two case studies, many companies are incorporating environmental cost information into their accounting systems to prioritize investments in new technologies and products.     

Evaluating options in LCA: The emergence of conflicting paradigms for impact assessment and evaluation

LCA aims to help direct decisions in an environmentally sustainable direction. It indicates the environmental effects of choices and evaluates these against this background. Approaches to evaluation in LCA differ substantially, related to the way of modelling environmental effects and to the way these effects are combined into an overall judgement on alternative options. Several approaches are now operational, which are linked to different paradigms in decision making. It is shown that the choice of paradigm is quite decisive on the outcome of the analysis. Also within similar paradigms, different methods now operational may lead to different outcomes. These latter differences may be alleviated more easily than those related to paradigmatic choices, as they are partly a matter of refinement, and they partly result from legitimate differences in subjective priorities. The more basic paradigmatic differences can hardly be bridged. The practical relevancy of the subject is proven by applying different operational methods to one case, showing widely differing outcomes. The paradigm behind evaluating environmental effects is either values based, directly or through policy decisions, or economics based, as individual preferences measured in the monetary terms of willingness-to-pay. Accordingly, the different methods are “policy-oriented” or “monetary”. It may be doubted if the differences between these can be overcome in standardisation.     

Application of Life Cycle Assessment for the Environmental Certificate of the Mercedes-Benz S-Class (7 pp)

Background, Aims and Scope Life cycle assessment (LCA) is used as a tool for design for environment (DfE) to improve the environmental performance of the Mercedes Car Group products. For the new S-Class model a brochure including an environmental certificate and comprehensive data for the product was published for the first time. The paper explains the use of LCA for these applications and presents exemplary results. Methods The environmental certificate brochure reports on processes, data and results based on the international standards for life cycle assessment (ISO 14040, ISO 14041, ISO 14042, ISO 14043), for environmental labels and declarations (ISO 14020, ISO 14021) and for the integration of environmental aspects into product design and development (ISO 14062), which are accepted by all stakeholders. Results and Discussion The compliance with these international standards and the correctness of the information contained in the certificate were reviewed and certified by independent experts. The global warming potential (GWP 100 years) of the new S-Class vehicle was reduced by 6%, the acidification potential by 2%, the eutrophication potential by 13% and the photochemical ozone creation potential by 9%. In addition, the use of parts made from renewable materials was increased by 73 percent to a total of 27 parts with a weight of about 43 kilograms. A total of 45 parts with a weight of 21.2 kilograms can be manufactured using a percentage of recycled plastics. Conclusion The application of LCA for DfE is fully integrated as a standard function in the vehicle development process. The DfE/LCA approach at the Mercedes Car Group was successful in improving the environmental performance of the new S-Class. It is shown that the objective of improving the environmental performance of the new S-Class model, compared to the previous one, was achieved. Recommendation and Outlook Vehicles are complex products with very complex interactions with the environment. Therefore, simple solutions, e.g. pure focus on fuel economy or light weighting or recycling or single material strategies, are bound to fail. It is a main task of DfE and LCA to take this fact into account and come up with more intelligent solutions. The application of LCAs for DfE and their integration as standard practice in the product development process is both the most demanding and the most rewarding. It requires a substantial effort to acquire the know-how, the data, the experience and the tools needed to generate meaningful results just in time. However, this is the way how LCA and DfE can add value – they have to be 'built' into the product.     

Time Horizon and Dominance in Dynamic Life Cycle Assessment

Temporal aspects have traditionally not been recognized adequately in life cycle assessment (LCA). The dynamic LCA model recently proposed offers a significant step forward in the dynamic assessment of global warming impacts. The results obtained with dynamic LCA are highly sensitive to the choice of a time horizon. Therefore, decision making between alternative systems can be critical because conclusions are dependent on the specific time horizon. In this article, we develop a decision‐making methodology based on the concept of time dominance. We introduce instantaneous and cumulative time dominance criteria to the dynamic LCA context and argue why the dominance of an alternative should also imply preference. Our approach allows for the rejection of certain alternatives without the determination of a specific time horizon. The number of decision‐relevant alternatives can thereby be reduced and the decision problem facilitated. We demonstrate our methodology by means of a case study of end‐of‐life alternatives for a wooden chair derived from the original authors of dynamic LCA and discuss the implications and limitations of the approach. The methodology based on time dominance criteria is supplementary to the dynamic LCA model, but does not substitute it. The overall value of this article stretches beyond LCA onto more general assessments of global warming, for example, in policy where the choice of a time horizon is equally significant.     

Usability of national reporting data as a reference for generic unit processes

Background, aim and scope  Renewable energy sources nowadays constitute an increasingly important issue in our society, basically because of the need for alternative sources of energy to fossil fuels that are free of CO₂ emissions and pollution and also because of other problems such as the diminution of the reserves of these fossil fuels, their increasing prices and the economic dependence of non-producers countries on those that produce fossil fuels. One of the renewable energy sources that has experienced a bigger growth over the last years is wind power, with the introduction of new wind farms all over the world and the new advances in wind power technology. Wind power produces electrical energy from the kinetic energy of the wind without producing any pollution or emissions during the conversion process. Although wind power does not produce pollution or emissions during operation, it should be considered that there is an environmental impact due to the manufacturing process of the wind turbine and the disposal process at the end of the wind turbine life cycle, and this environmental impact should be quantified in order to compare the effects of the production of energy and to analyse the possibilities of improvement of the process from that point of view. Thus, the aim of this study is to analyse the environmental impact of wind energy technology, considering the whole life cycle of the wind power system, by means of the application of the ISO 14040 standard [ISO (1998) ISO 14040. Environmental management—life cycle assessment—principles and framework. International Standard Organization, Geneva, Switzerland], which allows quantification of the overall impact of a wind turbine and each of its component parts using a Life Cycle Assessment (LCA) study. Materials and methods  The procedures, details, and results obtained are based on the application of the existing international standards of LCA. In addition, environmental details and indications of materials and energy consumption provided by the various companies related to the production of the component parts are certified by the application of the environmental management system ISO 14001 [ISO (2004) ISO 14001 Environmental management systems—requirements with guidance for use. International Standard Organization, Geneva, Switzerland]. A wind turbine is analysed during all the phases of its life cycle, from cradle to grave, by applying this methodology, taking into account all the processes related to the wind turbine: the production of its main components (through the incorporation of cut-off criteria), the transport to the wind farm, the subsequent installation, the start-up, the maintenance and the final dismantling and stripping down into waste materials and their treatment. The study has been developed in accordance with the ISO 14044 standard [ISO (2006) ISO 14044: Environmental management—life cycle assessment—requirements and guidelines. International Standard Organization, Geneva, Switzerland] currently in force. Results  The application of LCA, according to the corresponding international standards, has made it possible to determine and quantify the environmental impact associated with a wind turbine. On the basis of this data, the final environmental effect of the wind turbine after a lifespan of 20 years and its subsequent decommissioning have been studied. The environmental advantages of the generation of electricity using wind energy, that is, the reduction in emissions and contamination due to the use of a clean energy source, have also been evaluated. Discussion  This study concludes that the environmental pollution resulting from all the phases of the wind turbine (manufacture, start-up, use, and dismantling) during the whole of its lifetime is recovered in less than 1 year. Conclusions  From the developed LCA model, the important levels of contamination of certain materials can be obtained, for instance, the prepreg (a composite made by a mixture of epoxy resin and fibreglass). Furthermore, it has been concluded that it is possible to reduce the environmental effects of manufacturing and recycling processes of wind turbines and their components. Recommendations and perspectives  In order to achieve this goal in a fast and effective way, it is essential to enlist the cooperation of the different manufacturers.     

可持续消费的内涵及研究进展——产业生态学视角

生产和消费是产生诸多环境问题的根本原因,而可持续生产和消费则是实现可持续发展的根本途径。基于产业生态学视角,界定了可持续消费的定义及内涵,认为可持续消费首先须符合代内公平、代际公平和资源能源永续合理利用等可持续理念;其次辨识了可持续消费研究依次经历关注消费者行为直接环境影响、关注产品和服务生命周期环境影响到关注消费者责任3个阶段;最后结合我国城市化、工业化背景,提出我国可持续消费研究应该以城市居民为重点、加强生命周期数据库建设和内注重可持续生产等建议。     

Ambiguities in decision-oriented Life Cycle Inventories The Role of mental models

If the complexity of real, socio-economic systems is acknowledged, life cycle inventory analysis (LCI) in life cycle assessment (LCA) cannot be considered as unambiguous, objective, and as an exclusively data and science based attribution of material and energy flows to a product. The paper thus suggests a set of criteria for LCI derived from different scientific disciplines, practice of product design and modelling characteristics of LCI and LCA. A product system with its respective LCI supporting the process of effective and efficient decision-making should ideally be: a) complete, operational, decomposable, non-redundant, minimal, and comparable; b) efficient, i.e., as simple, manageable, transparent, cheap, quick, but still as ‘adequate’ as possible under a functionalistic perspective which takes given economic constraints, material and market characteristics, and the goal and scope of the study into account; c) actor-based when reflecting the decision-makers’ action space, risk-level, values, and knowledge (i.e. mental model) in view of the management rules of sustainable development; d) as site- and case-specific as possible, i.e. uses as much site-specific information as possible. This rationale stresses the significance of considering both (i) material and energy flows within the technosphere with regard to the sustainable management rules; (ii) environmental consequences of the environmental interventions on ecosphere. Further, the marginal cost of collecting and computing more and better information about environmental impacts must not exceed the marginal benefits of information for the natural environment. The ratio of environmental benefits to the economic cost of the tool must be efficient compared to other investment options. As a conclusion, in comparative LCAs, the application of equal allocation procedures does not lead to LCA-results on which products made from different materials can be compared in an adequate way. Each product and material must be modelled according to its specific material and market characteristics as well as to its particular management rules for their sustainable use. A generic LCA-methodology including preferences on methodological options is not definable.     

Philosophy of science, policy sciences and the basis of decision support with LCA Based on the toxicity controversy in Sweden and the Netherlands

Current LCA implicitly assumes that a single rational truth can be found. Mainstream policy sciences has taken a different starting point when analysing decision making in complex and controversial societal debates for already several decades. In such debates, in general, more than one reasonable conceptualisation or ‘framing’ of the problem is at stake which forms the core of the controversy. This paper analyses the Dutch chlorine debate and the Swedish PVC debate and shows that (three) frames also play a role in toxicity controversies: the risk assessment frame, the strict control frame, and the precautionary frame. The latter frame, adhered to by the environmentalists, seeks to judge substances mainly on their inherent safety. The cases show that this logic may be defended as at least being equally reasonable to the emission-effect calculations that form the core of Risk Assessment and Life-cycle Impact Assessment (LCIA). As predicted by policy sciences, this finding implies that the political neutrality of tools like LCIA is questionable. In summary, the approaches and procedures developed for LCA have to be reconciled with key lessons from policy science and philosophy of science, i.e. considering the fact that multiple realities play a key role in many decision making processes. This paper suggests some alternative indicators for toxicity evaluations, and indicates the implications of LCA method development.     

Integration of life cycle assessment in the environmental information system

Background, aim, and scope  As the sustainability improvement becomes an essential business task of industry, a number of companies are adopting IT-based environmental information systems (EIS). Life cycle assessment (LCA), a tool to improve environmental friendliness of a product, can also be systemized as a part of the EIS. This paper presents a case of an environmental information system which is integrated with online LCA tool to produce sets of hybrid life cycle inventory and examine its usefulness in the field application of the environmental management. Main features  Samsung SDI Ltd., the producer of display panels, has launched an EIS called Sustainability Management Initiative System (SMIS). The system comprised modules of functions such as environmental management system (EMS), green procurement (GP), customer relation (e-VOC), eco-design, and LCA. The LCA module adopted the hybrid LCA methodology in the sense that it combines process LCA for the site processes and input–output (IO) LCA for upstream processes to produce cradle-to-gate LCA results. LCA results from the module are compared with results of other LCA studies made by the application of different methodologies. The advantages and application of the LCA system are also discussed in light of the electronics industry. Results and discussion  LCA can play a vital role in sustainability management by finding environmental burden of products in their life cycle. It is especially true in the case of the electronics industry, since the electronic products have some critical public concerns in the use and end-of-life phase. SMIS shows a method for hybrid LCA through online data communication with EMS and GP module. The integration of IT-based hybrid LCA in environmental information system was set to begin in January 2006. The advantage of the comparing and regular monitoring of the LCA value is that it improves the system completeness and increases the reliability of LCA. By comparing the hybrid LCA and process LCA in the cradle-to-gate stage, the gap between both methods of the 42-in. standard definition plasma display panel (PDP) ranges from 1% (acidification impact category) to −282% (abiotic resource depletion impact category), with an average gap of 68.63%. The gaps of the impact categories of acidification (AP), eutrophication (EP), and global warming (GWP) are relatively low (less than 10%). In the result of the comparative analysis, the strength of correlation of three impact categories (AP, EP, GWP) shows that it is reliable to use the hybrid LCA when assessing the environmental impacts of the PDP module. Hybrid LCA has its own risk on data accuracy. However, the risk is affordable when it comes to the comparative LCA among different models of similar product line of a company. In the results of 2 years of monitoring of 42-in. Standard definition PDP, the hybrid LCA score has been decreased by 30%. The system also efficiently shortens man-days for LCA study per product. This fact can facilitate the eco-design of the products and can give quick response to the customer's inquiry on the product's eco-profile. Even though there is the necessity for improvement of process data currently available, the hybrid LCA provides insight into the assessments of the eco-efficiency of the manufacturing process and the environmental impacts of a product. Conclusions and recommendations  As the environmental concerns of the industries increase, the need for environmental data management also increases. LCA shall be a core part of the environmental information system by which the environmental performances of products can be controlled. Hybrid type of LCA is effective in controlling the usual eco-profile of the products in a company. For an industry, in particular electronics, which imports a broad band of raw material and parts, hybrid LCA is more practicable than the classic LCA. Continuous efforts are needed to align input data and keep conformity, which reduces data uncertainty of the system.     

Methodological Aspects of Applying Life Cycle Assessment to Industrial Symbioses

In view of recent studies of the historical development and current status of industrial symbiosis (IS), life cycle assessment (LCA) is proposed as a general framework for quantifying the environmental performance of by‐product exchange. Recent guidelines for LCA (International Reference Life Cycle Data System [ILCD] guidelines) are applied to answer the main research questions in the IS literature reviewed. A typology of five main research questions is proposed: (1) analysis, (2) improvement, and (3) expansion of existing systems; (4) design of new eco‐industrial parks, and (5) restructuring of circular economies. The LCA guidelines were found useful in framing the question and choosing an appropriate reference case for comparison. The selection of a correct reference case reduces the risk of overestimating the benefits of by‐product exchange. In the analysis of existing systems, environmentally extended input‐output analysis (EEIOA) can be used to streamline the analysis and provide an industry average baseline for comparison. However, when large‐scale changes are applied to the system, more sophisticated tools are necessary for assessment of the consequences, from market analysis to general equilibrium modeling and future scenario work. Such a rigorous application of systems analysis was not found in the current IS literature, but would benefit the field substantially, especially when the environmental impact of large‐scale economic changes is analyzed.