Purpose
Weighting is one of the steps involved in life cycle impact assessment (LCIA). This enables us to integrate various environmental impacts and facilitates the interpretation of environmental information. Many different weighting methodologies have already been proposed, and the results of many case studies with a single index have been published. However, a number of problems still remain. Weighting factors should be based on the preferences of society as a whole so that the life cycle assessment (LCA) practitioner can successfully apply them to every product and service. However, most existing studies do not really measure national averages but only the average of the responses obtained from the people actually sampled. Measuring the degree of uncertainty in LCIA factors is, therefore, one of the most important issues in current LCIA research, and some advanced LCIA methods have tried to deal with the problem of uncertainty. However, few weighting methods take into account the variability between each individual’s environmental thoughts. LIME2, the updated version of life cycle impact assessment method based on endpoint modeling (LIME), has been developed as part of the second LCA national project of Japan. One of the aims of LIME2 is to develop new weighting factors which fulfill the following requirements: (1) to accurately represent the environmental attitudes of the Japanese public, (2) to measure the variability between each individual’s environmental thoughts and reflect them in the choice of suitable weighting factors. 相似文献Purpose
In the European Union project New Energy Externalities Development for Sustainability (NEEDS), power generation technologies were ranked by means of two sustainability assessment approaches. The total costs approach, adding private and external costs, and a multi-criteria decision analysis (MCDA) were used, integrating social, economic and environmental criteria. Both approaches relied on environmental indicators based on life cycle assessment. This study aims to analyse the extent to which the development of life cycle sustainability assessment (LCSA) can draw on these ranking methods.Methods
The approaches to rank technologies in the NEEDS project are reviewed in terms of similarities and differences in concept, quantification and scope. Identified issues are discussed and set into perspective for the development of a potential future LCSA framework.Results and discussion
The NEEDS MCDA and total costs considerably overlap regarding issues covered, except for several social aspects. Beyond total costs being limited to private and external costs, most notable conceptual differences concern the coverage of pecuniary (i.e. price change-induced) external effects, and potential double-counting for instance of resource depletion or specific cost components. External costs take account of the specific utility changes of those affected, requiring a rather high level of spatial and temporal detail. This allows addressing intra- and inter-generational aspects. Differences between both ranking methods and current LCSA methods concern the way weighting is performed, the social aspects covered and the classification of indicators according to the three sustainability dimensions. The methods differ in the way waste, accidents or intended impacts are taken into account. An issue regarding the definition of truly comparable products has also been identified (e.g. power plants).Conclusions
For the development of LCSA, the study suggests that taking a consequential approach allows assessing pecuniary effects and repercussions of adaptation measures, relevant for a sustainability context, and that developing a life cycle impact assessment for life cycle costing would provide valuable information. The study concludes with raising a few questions and providing some suggestions regarding the development of a consistent framework for LCSA: whether the analyses in LCSA shall be distinguished into the three dimensions of sustainable development at the inventory or the impact level also with the aim to avoid double-counting, whether or not LCSA will address exceptional events, whether or not benefits shall be accounted for and how to deal with methodological and value choices (e.g. through sensitivity analyses). 相似文献The 17 Sustainable Development Goals (SDGs) and their 169 targets pose the most important framework for sustainable development worldwide. However, the contributions of products and companies to the SDGs using social and environmental life cycle assessment (S-LCA; E-LCA) have not been thoroughly addressed in the scientific literature. The purpose of this research is therefore to identify product-related targets, derive suitable indicators and develop a social life cycle impact assessment (S-LCIA) method.
MethodsTo systematically select product-related targets, two questions are developed. The questions ask whether a product (a) has a direct impact on the achievement of the target or (b) if the companies along the life cycle that produce or offer the product have a direct influence on the achievement of the respective target. Suitable indicators are derived and adapted from generally accepted frameworks such as the Global Indicator Framework (GIF-SDG). To develop an S-LCIA method, the targets are translated into conditions beneficial or damaging to the achievement of the target to estimate the socio-economic impact of the product using a scale from +1 to ?1. In cases where the targets remain vague, a systematic five-step approach to derive a quantifiable target involving five steps is applied.
Results and discussionThe main contribution of this paper is to propose a coherent method to measure the contribution of products to the targets. All 17 SDGs and 61 of the 169 targets (36%) were evaluated as product-related. For 57% of the product-related targets, indicators from the GIF-SDGs could at least partly be used after slight adaptations, while for the remaining 43% of the product-related targets, indicators were taken from other frameworks or sources or had to be added. In total, 45 indicators have been identified to be suitable for assessing the potential contribution of products to the 61 targets. To illustrate the systematic five-step approach to quantitatively assess the contribution of products to the targets, five types of contribution functions are presented in detail.
ConclusionsThe presented method allows companies to analyse their impact and that of their products on the targets both within their own company and in the supply chain. As especially the latter is increasingly demanded by supply chain laws in different countries such as France, the Netherlands or the UK, the method fills an important research gap. However, future research to examine the proposed approach, the derived indicators and the impact assessment method is strongly encouraged.
相似文献Purpose
In social life cycle assessment (SLCA), to measure the social performance, it is necessary to consider the subcategory indicators related to each stakeholder dimension, such as workers, local community, society, consumers and value chain participants. Current methods in SLCA scientific literature consider a standard arbitrary linear score set to translate qualitative performances into a quantitative assessment for all subcategory indicators, i.e., it translate a A, B, C, D scoring into a 4, 3, 2, 1 ordinal scale. This assumption does not cover the complexity of the subcategory indicators in the social life cycle assessment phase. The aim of this paper is to set out a customized scoring and weighting approach for impact assessment in SLCA beyond the assumption of arbitrary linearity and equal weighting.Methods
This method overcomes the linearity assumption and develops specific value functions for each subcategory indicator and an approach to establish the weighting factors between the indicators for each social dimension (workers, local community, and society). The value function and weighting factors are based on the considered opinions of SLCA experts in Québec.Results and discussion
The results show that value functions with different shapes used to score the performance of the product within each subcategory indicator influence SLCA results and have the potential to reverse the conclusions. The customized score is more realistic than the linear score because it can better capture the complexity of the subcategory indicators based on SLCA expert judgment.Conclusions
Our approach addresses a methodological weakness of the impact assessment phase of SLCA through a more representative performance of the potential social impacts based on the judgment of the SLCA expert rather than a simplified assumption of linearity and equal weighting among indicators. This approach may be applied to all types of product systems.Recommendations
The value functions and weighting factors cannot be generalized for all cases and the proposed approach must be adapted for each study. We stopped at the aggregation of the subcategory indicators based on expert judgment at the stakeholder level. If a complete aggregation in a single score is required, we recommend developing a framework that accounts for the value judgment of the decision-maker rather than the SLCA expert.Background, aim, and scope
Many studies evaluate the results of applying different life cycle impact assessment (LCIA) methods to the same life cycle inventory (LCI) data and demonstrate that the assessment results would be different with different LICA methods used. Although the importance of uncertainty is recognized, most studies focus on individual stages of LCA, such as LCI and normalization and weighting stages of LCIA. However, an important question has not been answered in previous studies: Which part of the LCA processes will lead to the primary uncertainty? The understanding of the uncertainty contributions of each of the LCA components will facilitate the improvement of the credibility of LCA.Methodology
A methodology is proposed to systematically analyze the uncertainties involved in the entire procedure of LCA. The Monte Carlo simulation is used to analyze the uncertainties associated with LCI, LCIA, and the normalization and weighting processes. Five LCIA methods are considered in this study, i.e., Eco-indicator 99, EDIP, EPS, IMPACT 2002+, and LIME. The uncertainty of the environmental performance for individual impact categories (e.g., global warming, ecotoxicity, acidification, eutrophication, photochemical smog, human health) is also calculated and compared. The LCA of municipal solid waste management strategies in Taiwan is used as a case study to illustrate the proposed methodology.Results
The primary uncertainty source in the case study is the LCI stage under a given LCIA method. In comparison with various LCIA methods, EDIP has the highest uncertainty and Eco-indicator 99 the lowest uncertainty. Setting aside the uncertainty caused by LCI, the weighting step has higher uncertainty than the normalization step when Eco-indicator 99 is used. Comparing the uncertainty of various impact categories, the lowest is global warming, followed by eutrophication. Ecotoxicity, human health, and photochemical smog have higher uncertainty.Discussion
In this case study of municipal waste management, it is confirmed that different LCIA methods would generate different assessment results. In other words, selection of LCIA methods is an important source of uncertainty. In this study, the impacts of human health, ecotoxicity, and photochemical smog can vary a lot when the uncertainties of LCI and LCIA procedures are considered. For the purpose of reducing the errors of impact estimation because of geographic differences, it is important to determine whether and which modifications of assessment of impact categories based on local conditions are necessary.Conclusions
This study develops a methodology of systematically evaluating the uncertainties involved in the entire LCA procedure to identify the contributions of different assessment stages to the overall uncertainty. Which modifications of the assessment of impact categories are needed can be determined based on the comparison of uncertainty of impact categories.Recommendations and perspectives
Such an assessment of the system uncertainty of LCA will facilitate the improvement of LCA. If the main source of uncertainty is the LCI stage, the researchers should focus on the data quality of the LCI data. If the primary source of uncertainty is the LCIA stage, direct application of LCIA to non-LCIA software developing nations should be avoided. 相似文献Purpose
Life cycle assessment (LCA) has been increasingly implemented in analyzing the environmental performance of buildings and construction projects. To assess the life cycle environmental performance, decision-makers may adopt the two life cycle impact assessment (LCIA) approaches, namely the midpoint and endpoint models. Any imprudent usage of the two approaches may affect the assessment results and thus lead to misleading findings. ReCiPe, a well-known work, includes a package of LCIA methods to provide assessments on both midpoint and endpoint levels. This study compares different potential LCIA results using the midpoint and endpoint approaches of ReCiPe based on the assessment of a commercial building in Hong Kong.Methods
This paper examines 23 materials accounting for over 99 % of the environmental impacts of all the materials consumed in commercial buildings in Hong Kong. The midpoint and endpoint results are compared at the normalization level. A commercial building in Hong Kong is further studied to provide insights as a real case study. The ranking of impact categories and the contributions from various construction materials are examined for the commercial building. Influence due to the weighting factors is discussed.Results and discussion
Normalization results of individual impact categories of the midpoint and endpoint approaches are consistent for the selected construction materials. The difference in the two approaches can be detected when several impact categories are considered. The ranking of materials is slightly different under the two approaches. The ranking of impact categories demonstrates completely different features. In the case study of a commercial building in Hong Kong, the contributions from subprocesses are different at the midpoint and endpoint. The weighting factors can determine not only the contributions of the damage categories to the total environment, but also the value of a single score.Conclusions
In this research, the midpoint and endpoint approaches are compared using ReCiPe. Information is whittled down from the inventories to a single score. Midpoint results are comprehensive while endpoint results are concise. The endpoint approach which provides additional information of damage should be used as a supplementary to the midpoint model. When endpoint results are asked for, a LCIA method like ReCiPe that provides both the midpoint and endpoint analysis is recommended. This study can assist LCA designers to interpret the midpoint and endpoint results, in particular, for the assessment of commercial buildings in Hong Kong. 相似文献Purpose
The most efficient way to reduce the environmental impact of cement production is to replace Portland cement with alternative cementitious materials. These are most often industrial waste such as blast-furnace slags (GBFS) and coal combustion fly ashes (FA). However, a recent European directive no longer considers these products as waste but as by-products. Therefore, the impact of their production has to be considered. Within this new framework, this study develops an evaluation method of their environmental impacts.Method
This paper presents pre-existing methods and underlines their limits. Through our evaluation of these methods, it has become clear that the allocation procedure is necessary; however, results depend highly on the chosen allocation procedure. This study presents a new allocation method, based on the fact that both cement and the alternative materials, GBFS and FA, are produced by energy-intensive industries (cement iron and coal) which are all subjected to the European Union Greenhouse Gas Emission Trading System. In this carbon trading system, it is economically beneficial for industries to reduce their environmental impact, like for when, by example, by-products from one industry are used as alternative ‘green’ material by another industry. Our allocation coefficient is calculated so that the economic gains and losses are the same for all of the industries involved in these exchanges and provides the overall environmental benefit of the exchanges.Results and discussion
The discussion shows that whilst this method has much in common with other allocation methods, it is more accurate as it allocates the environmental costs fairly over the industries involved and is more robust because of its constant value. One of its limits is that it cannot be used for life cycle inventories; however, we test the possibility of choosing a coefficient from one impact category and applying it to all the others.Conclusion
Lastly, the technical term of the equation this paper presents could be employed for consequential life cycle assessment, to calculate the most environmental uses by-products could be put to. 相似文献The purpose of this study is to provide an integrated method to identify the resource consumption, environmental emission, and economic cost for mechanical product manufacturing from economic and ecological dimensions and ultimately to provide theoretical and data support of energy conservation and emission reduction for mechanical product manufacturing.
MethodsThe applied research methods include environmental life cycle assessment (LCA) and life cycle cost (LCC). In life cycle environmental assessment, the inventory data are referred from Chinese Life Cycle Database and midpoint approach and EDIP2003 and CML2001 models of life cycle impact assessment (LCIA) are selected. In life cycle cost assessment, three cost categories are considered. The proposed environment and cost assessment method is based on the theory of social willingness to pay for potential environmental impacts. With the WD615 Steyr engine as a case, life cycle environment and cost are analyzed and evaluated.
Results and discussionThe case study indicates that, in different life cycle phases, the trend of cost result is generally similar to the environmental impacts; the largest proportion of cost and environmental impact happened in the two phases of “material production” and “component manufacturing” and the smallest proportion in “material transport” and “product assembly.” The environmental impact category of Chinese resource depletion potential (CRDP) accounted for the largest proportion, followed by global warming potential (GWP) and photochemical ozone creation potential (POCP), whereas the impacts of eutrophication potential (EP) and acidification potential (AP) are the smallest. The life cycle “conventional cost” accounted for almost all the highest percentage in each phase (except “material transport” phase), which is more than 80% of the total cost. The “environmental cost” and “possible cost” in each phase are relatively close, and the proportion of which is far below the “conventional cost.”
ConclusionsThe proposed method enhanced the conventional LCA. The case results indicate that, in a life cycle framework, the environment and cost analysis results could support each other, and focusing on the environment and cost analysis for mechanical product manufacturing will contribute to a more comprehensive eco-efficiency assessment. Further research on the life cycle can be extended to phases of “early design,” “product use,” and “final disposal.” Other LCIA models and endpoint indicators are advocated for this environmental assessment. Environmental cost can also be further investigated, and the relevant social willingness to pay for more environmental emissions is advocated to be increased.
相似文献Background, aim, and scope
Life Cycle Assessment (LCA) is an emerging supporting tool designed to help practitioner in systematically assessing the environmental performance of selected product’s life cycle. A product’s life cycle includes the extraction of raw materials, production, and usage, and ends with waste treatment or disposal. Life cycle impact assessment (LCIA) as a part of LCA is a method used to derive the environmental burdens from selected product’s stages. LCIA is structured in classification, characterization, normalization and weighting. Presently most of the LCIA practices use European database to establish the characterization, normalization and weighting value. However, using these values for local LCA practice might not be able to reflect the actual Malaysian’s environmental scenario. The aim of this study is to create a Malaysian version of normalization and weighting value using the pollution database within Malaysia. 相似文献Currently, social, environmental, and economic risks and chances of bioeconomy are becoming increasingly a subject of applied sustainability assessments. Based on life cycle assessment (LCA) methodology, life cycle sustainability assessment (LCSA) aims to combine or integrate social, environmental, and economic assessments. In order to contribute to the current early stage of LCSA development, this study seeks to identify a practical framework for integrated LCSA implementation.
MethodsWe select possible indicators from existing suitable LCA and LCSA approaches as well as from the literature, and allocate them to a sustainability concept for holistic and integrated LCSA (HILCSA), based on the Sustainable Development Goals (SDGs). In order to conduct a practical implementation of HILCSA, we choose openLCA, because it offers the best current state and most future potential for application of LCSA. Therefore, not only the capabilities of the software and databases, but also the supported methods of life cycle impact assessments (LCIA) are evaluated regarding the requirements of the indicator set and goal and scope of future case studies.
Results and discussionThis study presents an overview of available indicators and LCIAs for bioeconomy sustainability assessments as well as their link to the SDGs. We provide a practical framework for HILCSA of regional bioeconomy, which includes an indicator set for regional (product and territorial) bioeconomy assessment, applicable with current software and databases, LCIA methods and methods of normalization, weighting, and aggregation. The implementation of HILCSA in openLCA allows an integrative LCSA by conducting all steps in a single framework with harmonized, aggregated, and coherent results. HILCSA is capable of a sustainability assessment in terms of planetary boundaries, provisioning system and societal needs, as well as communication of results to different stakeholders.
ConclusionsOur framework is capable of compensating some deficits of S-LCA, E-LCA, and economic assessments by integration, and shows main advantages compared to additive LCSA. HILCSA is capable of addressing 15 out of 17 SDGs. It addresses open questions and significant problems of LCSAs in terms of goal and scope, LCI, LCIA, and interpretation. Furthermore, HILCSA is the first of its kind actually applicable in an existing software environment. Regional bioeconomy sustainability assessment is bridging scales of global and regional effects and can inform stakeholders comprehensively on various impacts, hotspots, trade-offs, and synergies of regional bioeconomy. However, significant research needs in LCIAs, software, and indicator development remain.
相似文献Purpose
Distance-to-target (DTT) methods are weighting methods aimed at assessing the distance of an existing situation from a desired state (the target). Weighting factors in DTT methods could be based on calculation which is performed on normalization factors (NFs) developed for life cycle assessment (LCA). At present, some DTT weighting sets have been developed. However, there is no DTT weighting set assessing the distance of EU domestic impacts from the desired state set by EU binding or non-binding policy targets (e.g., those related to the “Climate and Energy Package” and the “Roadmap to a Resource Efficient Europe”).Methods
In the present work, a methodology to derive target references from policy-based targets in 2020 (TRs2020), both binding (A) and non-binding (B), is presented. Resulting target factors and DTT weighting factors are then compared to the current normalisation factors (based on 2010 normalization references). The resulting weighting factor (WF) sets are presented and discussed in light of their use for decision support in policy and business contexts. We applied the WF sets to characterization results to an example (the EU energy mix process) aiming at illustrating key differences and effects on the results.Results and discussion
The three reference sets (NRs2010, TRs2020A, and TRs2020B) show, in some impact categories, a relatively small difference. WFs referred to set A and set B result to be quite similar, with the only exception of water depletion impact category, for which a very relevant change is foreseen when considering the effect of the non-binding target of limiting the abstraction of water resource to 20 % of the available renewable water resources. This is mainly due to the higher difficulty in deriving quantitative targets from non-binding strategies and policies rather than from binding ones.Conclusions
The resulting weighting sets present strengths and limitations. The translation of policy targets into quantitative modifications to the baseline inventories appeared to be not a straightforward task, due to several reasons discussed in the paper (e.g., not all the policy targets are expressed in quantitative terms or can be translated into quantitative reductions and modifications of the elementary flows in the existing baseline inventories). Aiming at improving the effectiveness in supporting policies, further development of the methodology may be the integration with other DTT approaches such those based on carrying capacity, developed to integrate Earth’s carrying capacity concept and planetary boundaries.Purpose
Life cycle assessment (LCA) has become one of the most widespread environmental assessment tools during the last two decades. However, there are still impacts that are not yet fully integrated, including climate impacts of land use. This study contributes to the development process by testing a selection of recently proposed climate impacts assessment methods, some more focused on the impact of land use and others more focused on a product’s carbon life cycle.Methods
Several assessment methods have been proposed in recent years, with their development still being in progress. Of these methods, we selected three methods that are more focused on the product’s carbon life cycle, and two methods more focused on the impact of land use. We applied the methods to an LCA study comparing biomass-based polyethylene (PE) packaging via different production routes in order to identify their methodological and practical challenges.Results and discussion
We found that including the impact of land use and carbon cycles had a profound effect on the results for global warming impact potential. It changed the ranking among the different routes for PE production, sometimes making biomass-based PE worse than the fossil alternative. Especially, the methods accounting for long time lags between carbon emissions and uptake in forestry punished the wood-based routes. Moreover, the variation in the results was considerable, showing that although assessment methods for climate impact can be applied to biomass-based products, their outcomes are not yet robust.Conclusions
We recommend efforts to harmonize and reconcile different approaches for the assessment of climate impact of biomass-based products with regard to (1) how they consider time, (2) their applicability to both short and long rotation crops and (3) harmonization of concepts and terms used by the methods. We further recommend that all value laden methodological choices that are built into the methods, such as the choice of reference states/points, are made explicit and that the outcomes of different modelling choices are tested.Thomas MettierEmail: |