Showing papers in "International Journal of Life Cycle Assessment in 2014"

Environmental impacts of hybrid, plug-in hybrid, and battery electric vehicles—what can we learn from life cycle assessment?

Abstract: The purpose of this review article is to investigate the usefulness of different types of life cycle assessment (LCA) studies of electrified vehicles to provide robust and relevant stakeholder information. It presents synthesized conclusions based on 79 papers. Another objective is to search for explanations to divergence and “complexity” of results found by other overviewing papers in the research field, and to compile methodological learnings. The hypothesis was that such divergence could be explained by differences in goal and scope definitions of the reviewed LCA studies. The review has set special attention to the goal and scope formulation of all included studies. First, completeness and clarity have been assessed in view of the ISO standard’s (ISO 2006a, b) recommendation for goal definition. Secondly, studies have been categorized based on technical and methodological scope, and searched for coherent conclusions. Comprehensive goal formulation according to the ISO standard (ISO 2006a, b) is absent in most reviewed studies. Few give any account of the time scope, indicating the temporal validity of results and conclusions. Furthermore, most studies focus on today’s electric vehicle technology, which is under strong development. Consequently, there is a lack of future time perspective, e.g., to advances in material processing, manufacturing of parts, and changes in electricity production. Nevertheless, robust assessment conclusions may still be identified. Most obvious is that electricity production is the main cause of environmental impact for externally chargeable vehicles. If, and only if, the charging electricity has very low emissions of fossil carbon, electric vehicles can reach their full potential in mitigating global warming. Consequently, it is surprising that almost no studies make this stipulation a main conclusion and try to convey it as a clear message to relevant stakeholders. Also, obtaining resources can be observed as a key area for future research. In mining, leakage of toxic substances from mine tailings has been highlighted. Efficient recycling, which is often assumed in LCA studies of electrified vehicles, may reduce demand for virgin resources and production energy. However, its realization remains a future challenge. LCA studies with clearly stated purposes and time scope are key to stakeholder lessons and guidance. It is also necessary for quality assurance. LCA practitioners studying hybrid and electric vehicles are strongly recommended to provide comprehensive and clear goal and scope formulation in line with the ISO standard (ISO 2006a, b).

Assessing resource depletion in LCA: a review of methods and methodological issues

Abstract: Political interest in the future availability of natural resources has spiked recently, with new documents from the European Union, United Nations Environment Programme and the US National Research Council assessing the supply situation of key raw materials. As resource efficiency is considered a key element for sustainable development, suitable methods to address sustainability of resource use are increasingly needed. Life cycle thinking and assessment may play a principal role here. Nonetheless, the extent to which current life cycle impact assessment methods are capable to answer to resource sustainability challenges is widely debated. The aim of this paper is to present key elements of the ongoing discussion, contributing to the future development of more robust and comprehensive methods for evaluating resources in the life cycle assessment (LCA) context. We systematically review current impact assessment methods dealing with resources, identifying areas of improvement. Three key issues for sustainability assessment of resources are examined: renewability, recyclability and criticality; this is complemented by a cross-comparison of methodological features and completeness of resource coverage. The approach of LCA to resource depletion is characterised by a lack of consensus on methodology and on the relative ranking of resource depletion impacts as can be seen from a comparison of characterisation factors. The examined models yield vastly different characterisations of the impacts from resource depletion and show gaps in the number and types of resources covered. Key areas of improvement are identified and discussed. Firstly, biotic resources and their renewal rates have so far received relatively little regard within LCA; secondly, the debate on critical raw materials and the opportunity of introducing criticality within LCA is controversial and requires further effort for a conciliating vision and indicators. We identify points where current methods can be expanded to accommodate these issues and cover a wider range of natural resources.

LCA benchmarking study on textiles made of cotton, polyester, nylon, acryl, or elastane

Abstract: The purpose of this paper is to provide an improved (up-to-date) insight into the environmental burden of textiles made of the base materials cotton, polyester (PET), nylon, acryl, and elastane. The research question is: Which base material and which life cycle stage (cradle-to-gate as well as cradle-to-grave) have the biggest impact on the environment? Life cycle inventory (LCI) data are collected from the literature, life cycle assessment (LCA) databases, and emission registration database of the Dutch government, as well as communications with both manufacturing companies of production equipment and textile companies. The output of the calculations is presented in four single indicators: Eco-costs 2012 (a prevention-based indicator), CO2 equivalent (carbon footprint), cumulative energy demand (CED), and ReCiPe (a damage-based indicator). From an analysis of the data, it becomes clear that the environmental burden is not only a function of the base materials (cotton, PET, nylon, acryl, and elastane) but also of the thickness of the yarn (for this research, the range of 50–500 dtex is examined). The authors propose that the environmental burden of spinning, weaving, and knitting is a function of 1/yarn size. The cradle-to-grave analysis from raw material extraction to discarded textile demonstrates that textiles made out of acryl and PET have the least impact on the environment, followed by elastane, nylon, and cotton. The use phase has less relative impact than it is suggested in the classical literature. The impact of spinning and weaving is relatively high (for yarn thicknesses of less than 100 dtex), and from the environmental point of view, knitting is better than weaving. LCA on textiles can only be accurate when the yarn thickness is specified. In case the functional unit also indicates the fabric per square meter, the density must be known. LCA results of textile products over the whole value chain are case dependent, especially when dyeing and finishing processes and the use phase and end-of-life are included in the analysis. Further LCI data studies on textiles and garments are urgently needed to lower the uncertainties in contemporary LCA of textile materials and products.

Use of LCA as a development tool within early research:Challenges and issues across different sectors

Abstract: The aim of this paper is to highlight the challenges that face the use of life cycle assessment (LCA) for the development of emerging technologies. LCA has great potential for driving the development of products and processes with improved environmental credentials when used at the early research stage, not only to compare novel processing with existing commercial alternatives but to help identify environmental hotspots. Its use in this way does however provide methodological and practical difficulties, often exacerbated by the speed of analysis required to enable development decisions to be made. Awareness and understanding of the difficulties in such cases is vital for all involved with the development cycle. This paper employs three case studies across the diverse sectors of nanotechnology, lignocellulosic ethanol (biofuel), and novel food processes demonstrating both the synergy of issues across different sectors and highlighting the challenges when applying LCA for early research. Whilst several researchers have previously highlighted some of the issues with use of LCA techniques at an early stage, most have focused on a specific product, process development, or sector. The use of the three case studies here is specifically designed to highlight conclusively that such issues are prevalent to use of LCA in early research irrespective of the technology being assessed. The four focus areas for the paper are system boundaries, scaling issues, data availability, and uncertainty. Whilst some of the issues identified will be familiar to all LCA practitioners as problems shared with standard LCAs, their importance and difficulty is compounded by factors distinct to novel processes as emerging technology is often associated with unknown future applications, unknown industrial scales, and wider data gaps that contribute to the level of LCA uncertainty. These issues, in addition with others that are distinct to novel applications, such as the challenges of comparing laboratory scale data with well-established commercial processing, are exacerbated by the requirement for rapid analysis to enable development decisions to be made. Based on the challenges and issues highlighted via illustration through the three case studies, it is clear that whilst transparency of information is paramount for standard LCAs, the sensitivities, complexities, and uncertainties surrounding LCAs for early research are critical. Full reporting and understanding of these must be established prior to utilising such data as part of the development cycle.

Social life cycle assessment for material selection: a case study of building materials

Abstract: Purpose Sustainability of a material-based product mainly depends on the materials used for the product itself or during its lifetime. A material selection decision should not only capture the functional performance required but should also consider the economical, social, and environmental impacts originated during the product life cycle. There is a need to assess social impacts of materials along the full life cycle, not only to be able to address the “social dimension” in sustainable material selection but also for potentially improving the circumstances of affected stakeholders. This paper presents the method and a case study of social life cycle assessment (S-LCA) specialized for comparative studies. Although the authors’ focus is on material selection, the proposed methodology can be used for comparative assessment of products in general.

Life Cycle Assessment (LCA): A Guide to Best Practice

Abstract: INTRODUCTION What is Life Cycle Assessment (LCA)? History The Structure of LCA Standardization of LCA Literature and Information on LCA GOAL AND SCOPE DEFINITION Goal Definition Scope Illustration of the Component "Definition of Goal and Scope" unsing an Example of Practice LIFE CYCLE INVENTORY ANALYSIS Basics Energy Analysis Allocation Procurement, Origin and Quality of Data Data Aggregation and Units Presentation of Inventory Results Illustration of the Inventory Phase by an Example LIFE CYCLE IMPACT ASSESSMENT Basic Principle of Life Cycle Impact Assessment Method of Critical Volumes Structure of Impact Assessment according to ISO 14040 and 14044 Method of Impact Categories (Environmental Problem Fields) Impact Categories, Impact Indicators and Characterization Factors Illustration of the Impact Assessment Phase by Practical Example LIFE CYCLE INTERPRETATION, REPORTING AND CRITICAL REVIEW Development and Rank of the Phase Interpretation The Phase Interpretation According to ISO Techniques for Result Analysis Reporting Critical Review Illustration of the Component Interpretation Using an Example of Practice FROM LCA TO SUSTAINABILITY ASSESSMENT Sustainability The Three Dimensions of Sustainability State of the Art of Methods One Life Cycle Assessment or Three? Conclusions APPENDIX Solutions of Exercises Standard Report Sheet of Electricity Mix (Germany) Subject Index

Integrating triple bottom line input–output analysis into life cycle sustainability assessment framework: the case for US buildings

Abstract: With the increasing concerns related to integration of social and economic dimensions of the sustainability into life cycle assessment (LCA), traditional LCA approach has been transformed into a new concept, which is called as life cycle sustainability assessment (LCSA). This study aims to contribute the existing LCSA framework by integrating several social and economic indicators to demonstrate the usefulness of input–output modeling on quantifying sustainability impacts. Additionally, inclusion of all indirect supply chain-related impacts provides an economy-wide analysis and a macro-level LCSA. Current research also aims to identify and outline economic, social, and environmental impacts, termed as triple bottom line (TBL), of the US residential and commercial buildings encompassing building construction, operation, and disposal phases. To achieve this goal, TBL economic input–output based hybrid LCA model is utilized for assessing building sustainability of the US residential and commercial buildings. Residential buildings include single and multi-family structures, while medical buildings, hospitals, special care buildings, office buildings, including financial buildings, multi-merchandise shopping, beverage and food establishments, warehouses, and other commercial structures are classified as commercial buildings according to the US Department of Commerce. In this analysis, 16 macro-level sustainability assessment indicators were chosen and divided into three main categories, namely environmental, social, and economic indicators. Analysis results revealed that construction phase, electricity use, and commuting played a crucial role in much of the sustainability impact categories. The electricity use was the most dominant component of the environmental impacts with more than 50 % of greenhouse gas emissions and energy consumption through all life cycle stages of the US buildings. In addition, construction phase has the largest share in income category with 60 % of the total income generated through residential building’s life cycle. Residential buildings have higher shares in all of the sustainability impact categories due to their relatively higher economic activity and different supply chain characteristics. This paper is an important attempt toward integrating the TBL perspective into LCSA framework. Policymakers can benefit from such approach and quantify macro-level environmental, economic, and social impacts of their policy implications simultaneously. Another important outcome of this study is that focusing only environmental impacts may misguide decision-makers and compromise social and economic benefits while trying to reduce environmental impacts. Hence, instead of focusing on environmental impacts only, this study filled the gap about analyzing sustainability impacts of buildings from a holistic perspective.

Life cycle greenhouse gas emissions of blended cement concrete including carbonation and durability

Abstract: Purpose Blended cements use waste products to replace Portland cement, the main contributor to CO2 emissions in concrete manufacture. Using blended cements reduces the embodied greenhouse gas emissions; however, little attention has been paid to the reduction in CO2 capture (carbonation) and durability. The aim of this study is to determine if the reduction in production emissions of blended cements compensates for the reduced durability and CO2 capture.

Life cycle assessment of bio-based ethanol produced from different agricultural feedstocks

Abstract: Bio-based products are often considered sustainable due to their renewable nature. However, the environmental performance of products needs to be assessed considering a life cycle perspective to get a complete picture of potential benefits and trade-offs. We present a life cycle assessment of the global commodity ethanol, produced from different feedstock and geographical origin. The aim is to understand the main drivers for environmental impacts in the production of bio-based ethanol as well as its relative performance compared to a fossil-based alternative. Ethanol production is assessed from cradle to gate; furthermore, end-of-life emissions are also included in order to allow a full comparison of greenhouse gas (GHG) emissions, assuming degradation of ethanol once emitted to air from household and personal care products. The functional unit is 1 kg ethanol, produced from maize grain in USA, maize stover in USA, sugarcane in North-East of Brazil and Centre-South of Brazil, and sugar beet and wheat in France. As a reference, ethanol produced from fossil ethylene in Western Europe is used. Six impact categories from the ReCiPe assessment method are considered, along with seven novel impact categories on biodiversity and ecosystem services (BES). GHG emissions per kilogram bio-based ethanol range from 0.7 to 1.5 kg CO2 eq per kg ethanol and from 1.3 to 2 kg per kg if emissions at end-of-life are included. Fossil-based ethanol involves GHG emissions of 1.3 kg CO2 eq per kg from cradle-to-gate and 3.7 kg CO2 eq per kg if end-of-life is included. Maize stover in USA and sugar beet in France have the lowest impact from a GHG perspective, although when other impact categories are considered trade-offs are encountered. BES impact indicators show a clear preference for fossil-based ethanol. The sensitivity analyses showed how certain methodological choices (allocation rules, land use change accounting, land use biomes), as well as some scenario choices (sugarcane harvest method, maize drying) affect the environmental performance of bio-based ethanol. Also, the uncertainty assessment showed that results for the bio-based alternatives often overlap, making it difficult to tell whether they are significantly different. Bio-based ethanol appears as a preferable option from a GHG perspective, but when other impacts are considered, especially those related to land use, fossil-based ethanol is preferable. A key methodological aspect that remains to be harmonised is the quantification of land use change, which has an outstanding influence in the results, especially on GHG emissions.

Error propagation methods for LCA—a comparison

Abstract: The analysis of uncertainty in life cycle assessment (LCA) studies has been a topic for more than 10 years, and many commercial LCA programs now feature a sampling approach called Monte Carlo analysis. Yet, a full Monte Carlo analysis of a large LCA system, for instance containing the 4,000 unit processes of ecoinvent v2.2, is rarely carried out by LCA practitioners. One reason for this is computation time. An alternative faster than Monte Carlo method is analytical error propagation by means of a Taylor series expansion; however, this approach suffers from being explained in the literature in conflicting ways, hampering implementation in most software packages for LCA. The purpose of this paper is to compare the two different approaches from a theoretical and practical perspective. In this paper, we compare the analytical and sampling approaches in terms of their theoretical background and their mathematical formulation. Using three case studies—one stylized, one real-sized, and one input–output (IO)-based—we approach these techniques from a practical perspective and compare them in terms of speed and results. Depending on the precise question, a sampling or an analytical approach provides more useful information. Whenever they provide the same indicators, an analytical approach is much faster but less reliable when the uncertainties are large. For a good analysis, analytical and sampling approaches are equally important, and we recommend practitioners to use both whenever available, and we recommend software suppliers to implement both.

Comparing the midpoint and endpoint approaches based on ReCiPe—a study of commercial buildings in Hong Kong

Abstract: 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. 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. 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. 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.

IMPACT 2002+, ReCiPe 2008 and ILCD’s recommended practice for characterization modelling in life cycle impact assessment: a case study-based comparison

Abstract: Purpose The European Commission has launched a recommended set of characterization models and factors for application in life cycle impact assessment (LCIA). However, it is not known how this recommended practice, referred to as the ILCD 2009, performs relative to some of the most frequently used alternative LCIA methodologies. Here, we compare the ILCD 2009 with IMPACT 2002+ and ReCiPe 2008, focusing on characterization at midpoint based on a case study comparing four window design options for use in a residential building.

Product environmental footprint—breakthrough or breakdown for policy implementation of life cycle assessment?

Abstract: Did you hear about the latest footprint? It is not anymore about carbon footprinting (Finkbeiner 2009) or water footprinting (Kounina et al. 2013; Berger and Finkbeiner 2010); we now have to deal with environmental footprints. The EU Commission published the Product Environmental Footprint (PEF) and Organisation Environmental Footprint (OEF) methods (EU 2013a) as part of the Communication “Building the Single Market for Green Products” (EU 2013b). According to the documents released, the PEF and OEF methodologies build on existing life cycle assessment (LCA)-based methods and aim at harmonizing them. They purportedly aim at increasing comparability between products by predefining requirements for certain methodological aspects, thus decreasing the flexibility provided by ISO 14044 (2006). PEF and OEF were developed by the European Commission's Joint Research Centre (JRC). But is PEF really the breakthrough for policy implementation of LCA? Close analysis of the PEF method reveals key concerns from the perspective of state-ofthe-art LCA practice and science. Rather than proposing a harmonized compromise of existing standards, it presents an entirely new one which is even in conflict with the existing ISO 14044 (2006). As such, PEF does not contribute to harmonization, but rather to confusion, proliferation, and mistrust. 1 Do we really need another footprint?

Stochastic decision modeling for sustainable pavement designs

Abstract: Purpose In the USA, several studies have been conducted to analyze the energy consumption and atmospheric emissions of Warm-mix Asphalt (WMA) pavements. However, the direct and indirect environmental, economic, and social impacts, termed as Triple-Bottom-Line (TBL), were not addressed sufficiently. Hence, the aim of this study is to develop TBLoriented sustainability assessment model to evaluate the environmental and socio-economic impacts of pavements constructed with different types of WMA mixtures and compare them to a conventional Hot-mix Asphalt (HMA). The types of WMA technologies investigated in this research include Asphamin® WMA, Evotherm™ WMA, and Sasobit® WMA. Methods Toachievethisgoal,supplyandusetablespublished by the U.S. Bureau of Economic Analysis were merged with 16 macro-level sustainability metrics. A hybrid TBL-LCA model was built to evaluate the life-cycle sustainability performance of using WMA technologies in construction of asphalt pavements. The impacts on the sustainability were calculated in terms of socio-economic (import, income, gross operating surplus, government tax, work-related injuries, and employment) and environmental (water withdrawal, energy use, carbon footprint, hazardous waste generation, toxic releases into air, and land use). A stochastic compromise programming model was then developed for finding the optimal allocation of different pavement types for the U.S. highways. Results and discussion WMAsdid not perform betterinterms of environmental impacts compared to HMA. Asphamin® WMA was found to have the highest environmental and socio-economic impacts compared to other pavement types. Material extractions and processing phase had the highest contribution to all environmental impact indicators that shows the importance of cleaner production strategies for pavement materials. Based on stochastic compromised programming results, in a balanced weighting situation, Sasobit® WMA had the highest percentage of allocation (61 %); while only socio-economic aspects matter, Asphamin® WMA had the largest share (57 %) among the asphalt pavements. The optimization results also supported the significance of an increased WMA use in the U.S. highways. Conclusions This research complemented previous LCA studies by evaluating pavements not only from environmental emissions and energy consumption standpoint, but also from socio-economicperspectives.Multi-objectiveoptimizationresults also provided important insights for decision makers whenfinding the optimum allocationof pavement alternatives based on different environmental and socio-economic priorities. Consequently, this study aimed to increase awareness of the inherent benefits of economic input–output analysis and multi-criteria decision making through application to emerging sustainable pavement practices.

On the uncanny capabilities of consequential LCA

Abstract: Purpose Plevin et al. (2014) reviewed relevant life cycle assessment (LCA) studies for biofuels and argued that the use of attributional LCA (ALCA) for estimating the benefits of biofuel policy is misleading. While we agree with the authors on many points, we found that some of the arguments by the authors were not presented fairly and that a number of specific points warrant additional comment. The main objective of this commentary is to examine the authors’ comparative statements between consequential LCA (CLCA) and ALCA.

Comparative life cycle assessment of smartphone reuse: repurposing vs. refurbishment

Abstract: Purpose Waste management for end-of-life (EoL) smartphones is a growing problem due to their high turnover rate and concentration of toxic chemicals The versatility of modern smartphones presents an interesting alternative waste management strategy: repurposing This paper investigates the environmental impact of smartphone repurposing as compared to traditional refurbishing using Life Cycle Assessment (LCA) Methods A case study of repurposing was conducted by creating a smartphone “app” that replicates the functionality of an in-car parking meter The environmental impacts of this prototype were quantified using waste management LCA methodology Studied systems included three waste management options: traditional refurbishment, repurposing using battery power, and repurposing using a portable solar charger The functional unit was defined as the EoL management of a used smartphone Consequential system expansion was employed to account for secondary functions provided; avoided impacts from displaced primary products were included Impacts were calculated in five impact categories Break-even displacement rates were calculated and sensitivity to standby power consumption were assessed Results and discussion LCA results showed that refurbishing creates the highest environmental impacts of the three reuse routes in every impact category except ODP High break-even displacement rates suggest that this finding is robust within a reasonable range of primary cell phone displacement The repurposed smartphone in-car parking meter had lower impacts than the primary production parking meter Impacts for battery-powered devices were dominated by use-phase charging electricity, whereas solar-power impacts were concentrated in manufacturing Repurposed phones using battery power had lower impacts than those using solar power, however, standby power sensitivity analysis revealed that solar power is preferred if the battery charger is left plugged-in more than 20 % of the use period Conclusions Our analysis concludes that repurposing represents an environmentally preferable EoL option to refurbishing for used smartphones The results suggest two generalizable findings First, primary product displacement is a major factor affecting whether any EoL strategy is environmentally beneficial The benefit depends not only on what is displaced, but also on how much displacement occurs; in general, repurposing allows freedom to target reuse opportunities with high “displacement potential” Second, the notion that solar power is preferable to batteries is not always correct; here, the rank-order is sensitive to assumptions about user behavior

Life cycle assessment of construction materials: the influence of assumptions in end-of-life modelling

Abstract: Purpose The nature of end-of-life (EoL) processes is highly uncertain for constructions built today. This uncertainty is often neglected in life cycle assessments (LCAs) of construction materials. This paper tests how EoL assumptions influence LCA comparisons of two alternative roof construction elements: glue-laminated wooden beams and steel frames. The assumptions tested include the type of technology and the use of attributional or consequential modelling approaches.

The economic resource scarcity potential (ESP) for evaluating resource use based on life cycle assessment

Abstract: In life cycle assessment (LCA), resource availability is currently evaluated by means of models based on depletion time, surplus energy, etc. Economic aspects influencing the security of supply and affecting availability of resources for human use are neglected. The aim of this work is the development of a new model for the assessment of resource provision capability from an economic angle, complementing existing LCA models. The inclusion of criteria affecting the economic system enables an identification of potential supply risks associated with resource use. In step with actual practice, such an assessment provides added value compared to conventional (environmental) resource assessment within LCA. Analysis of resource availability including economic information is of major importance to sustain industrial production. New impact categories and characterization models are developed for the assessment of economic resource availability based on existing LCA methodology and terminology. A single score result can be calculated providing information about the economic resource scarcity potential (ESP) of different resources. Based on a life cycle perspective, the supply risk associated with resource use can be assessed, and bottlenecks within the supply chain can be identified. The analysis can be conducted in connection with existing LCA procedures and in line with current resource assessment practice and facilitates easy implementation on an organizational level. A portfolio of 17 metals is assessed based on different impact categories. Different impact factors are calculated, enabling identification of high-risk metals. Furthermore, a comparison of ESP and abiotic depletion potential (ADP) is conducted. Availability of resources differs significantly when economic aspects are taken into account in addition to geologic availability. Resources assumed uncritical based on ADP results, such as rare earths, turn out to be associated with high supply risks. The model developed in this work allows for a more realistic assessment of resource availability beyond geologic finiteness. The new impact categories provide organizations with a practical measure to identify supply risks associated with resources. The assessment delivers a basis for developing appropriate mitigation measures and for increasing resilience towards supply disruptions. By including an economic dimension into resource availability assessment, a contribution towards life cycle sustainability assessment (LCSA) is achieved.

Integrating participatory approaches into social life cycle assessment: the SLCA participatory approach

Abstract: This article discusses the choice of stakeholder categories and the integration of stakeholders into participatory processes to define impact categories and select indicators. We undertook a literature review concerning the roles and the importance of stakeholders in participatory processes, and the use of such processes in environmental and social LCAs (Biswas et al. Int J Life Cycle Assess 3(4):184-190, 1998; Sonnemann et al. Int J Life Cycle Assess 6(6):325-333, 2001; Baldo Int J Life Cycle Assess 7(5):269-275, 2002; James et al. Int J Life Cycle Assess 7(3):151-157, 2002; Bras-Kapwijk Int J Life Cycle Assess 8(5):266-272, 2003; Mettier et al. Int J Life Cycle Assess 11(6):468-476, 2006). As part of the French National Research Agency Piscenlit project, we adapted the Principle, Criteria, Indicator (PCI) method (Rey-Valette et al. 2008), which is an assessment method of sustainable development, as a way to integrate the participatory approach into Social Life Cycle Assessment (SLCA) methodology, mainly at the impact definition stage. Different views of participation were found in the literature; there is no consensual normative approach for the implication of stakeholders in LCA development. Some attempts have been made to integrate stakeholders into environmental LCAs but these attempts have not been generalized. However, they strongly emphasize the interrelationship between research on the growing integration of stakeholders and on the choice of stakeholders. We then propose criteria from stakeholder theory (Freeman 1984; Mitchell et al. Acad Manage Rev 22(4):853-886, 1997; Geibler et al. Bus Strat Environ 15:334-346, 2006) in order to identify relevant stakeholders for SLCA participatory approach. The adaptation of the PCI method to Principles, Impacts, and Indicators (PII) enables stakeholders to express themselves and hence leads to definitions of relevant social indicators that they can appropriate. The paper presents results regarding the selection of stakeholders but no specific results regarding the choice of impact categories and indicators. Integrating a participatory approach into SLCAs is of interest at several levels. It enables various factors to be taken into account: plurality of stakeholder interests, local knowledge, and impact categories that make sense for stakeholders in different contexts. It also promotes dialogue and simplifies the search for indicators. However, it requires a multidisciplinary approach and the integration of new knowledge and skills for the SLCA practitioners.

The rebound effect through industrial ecology’s eyes: a review of LCA-based studies

Abstract: Industrial ecology academics have embraced with great interest the rebound effect principle operationalised within energy economics. By pursuing more comprehensive assessments, they applied tools such as life cycle assessment (LCA) to appraise the environmental consequences of the rebound effect. As a result, the mainstream rebound mechanism was broadened and a diversity of (sometimes inconsistent) definitions and approaches unveiled. To depict the state of play, a comprehensive literature review is needed. A literature review has been carried out by targeting scientific documents relevant for the integration of the rebound effect into LCA-based studies. The search was conducted using two approaches: (1) via online catalogues using a defined search criterion and (2) via cross-citation analysis from the documents identified through the first approach. By analysing a total of 42 works yielded during our review, it was possible to bring together the various advantages of the life cycle perspective, as well as to identify the main inconsistencies and uninformed claims present in literature. Concretely, three main advantages have been identified and are discussed: (1) the representation of the rebound effect as a multi-dimensional, life cycle estimate, (2) the improvement of the technology explicitness and (3) the broadening of the consumption and production factors leading to the rebound effect. Also, inconsistencies on the definition and classification of the rebound effect have been found among studies. The review contributes a number of valuable insights to understand how the rebound effect has been treated within the industrial ecology and LCA fields. For instance, the conceptual and methodological refinements introduced by these fields represent a step forward from traditional viewpoints, making the study of the rebound effect more comprehensive and meaningful for environmental assessment and policy making. However, the broadened scope of this new approach unveiled some conceptual inconsistencies, which calls for a common framework. This framework would help the LCA community to consistently integrate the rebound effect as well as to create a common language with other disciplines, favouring learning and co-evolution. We believe that our findings can serve as a starting point in order to delineate such a common framework.

A protocol for horizontal averaging of unit process data—including estimates for uncertainty

Abstract: Purpose Quantitative uncertainties are a direct consequence of averaging, a common procedure when building life cycle inventories (LCIs). This averaging can be amongst locations, times, products, scales or production technologies. To date, however, quantified uncertainties at the unit process level have largely been generated using a Numerical Unit Spread Assessment Pedigree (NUSAP) approach and often disregard inherent uncertainties (inaccurate measurements) and spread (variability around means).

Carbon sequestration in LCA, a proposal for a new approach based on the global carbon cycle; cases on wood and on bamboo

Abstract: There are many recent proposals in life cycle assessment (LCA) to calculate temporary storage of carbon in bio-based products. However, there is still no consensus on how to deal with the issue. The main questions are: how do these proposals relate to each other, to what extent are they in line with the classical LCA method (as defined in ISO 14044) and the global mass balances as proposed by the IPCC, and is there really a need to introduce a discounting system for delayed CO2 emissions? This paper starts with an analysis of the widely applied specification of PAS 2050 and the ILCD Handbook, both specifying the credit for carbon sequestration as ‘optional’ in LCA. From this analysis, it is concluded that these optional calculations give rather different results compared to the baseline LCA method. Since these optional calculations are not fully in line with the global carbon mass balances, a new calculation method is proposed. To validate the new method, two cases (one on wood and one bamboo products) are given. These cases show the practical application and the consequences of the new approach. Finally, the main issue is evaluated and discussed: is it a realistic approach to allocate less damage to the same emission, when it is released later in time? This paper proposes a new approach based on the global carbon cycle and land-use change, translated to the level of individual products in LCA. It is argued that only a global growth of forest area and a global growth of application of wood in the building industry contribute to extra carbon sequestration, which might be allocated as a credit to the total market of wood products in LCA. This approach is different from approaches where temporary storage of carbon in trees is directly allocated to a product itself. In the proposed approach, there seems to be no need for a discounting system of delayed CO2 emissions. The advantage of wood and wood-based products can be described in terms of land-use change on a global scale in combination with a credit for heat recovery at the end-of-life (if applicable).

Stochastic multi-attribute analysis (SMAA) as an interpretation method for comparative life-cycle assessment (LCA)

Abstract: Comparative life-cycle assessments (LCAs) today lack robust methods of interpretation that help decision makers understand and identify tradeoffs in the selection process. Truncating the analysis at characterization is misleading and existing practices for normalization and weighting may unwittingly oversimplify important aspects of a comparison. This paper introduces a novel approach based on a multi-criteria decision analytic method known as stochastic multi-attribute analysis for life-cycle impact assessment (SMAA-LCIA) that uses internal normalization by means of outranking and exploration of feasible weight spaces. To contrast different valuation methods, this study performs a comparative LCA of liquid and powder laundry detergents using three approaches to normalization and weighting: (1) characterization with internal normalization and equal weighting, (2) typical valuation consisting of external normalization and weights, and (3) SMAA-LCIA using outranking normalization and stochastic weighting. Characterized results are often represented by LCA software with respect to their relative impacts normalized to 100 %. Typical valuation approaches rely on normalization references, single value weights, and utilizes discrete numbers throughout the calculation process to generate single scores. Alternatively, SMAA-LCIA is capable of exploring high uncertainty in the input parameters, normalizes internally by pair-wise comparisons (outranking) and allows for the stochastic exploration of weights. SMAA-LCIA yields probabilistic, rather than discrete comparisons that reflect uncertainty in the relative performance of alternatives. All methods favored liquid over powder detergent. However, each method results in different conclusions regarding the environmental tradeoffs. Graphical outputs at characterization of comparative assessments portray results in a way that is insensitive to magnitude and thus can be easily misinterpreted. Typical valuation generates results that are oversimplified and unintentionally biased towards a few impact categories due to the use of normalization references. Alternatively, SMAA-LCIA avoids the bias introduced by external normalization references, includes uncertainty in the performance of alternatives and weights, and focuses the analysis on identifying the mutual differences most important to the eventual rank ordering. SMAA-LCIA is particularly appropriate for comparative LCAs because it evaluates mutual differences and weights stochastically. This allows for tradeoff identification and the ability to sample multiple perspectives simultaneously. SMAA-LCIA is a robust tool that can improve understanding of comparative LCA by decision or policy makers.

Subcategory assessment method for social life cycle assessment. Part 1: methodological framework

Abstract: The aim of this work is to propose an objective method for evaluating subcategories in social life cycle impact assessment (S-LCIA). Methods for assessing subcategories have been available since 2006, but a number of these either fail to include all the subcategories envisaged in the guidelines for S-LCA (UNEP/SETAC 2009) or are subjective in their assessment of each subcategory. The methodology is characterized by four steps: (i) the use of the organization as unit process, in which it was decided to assess the social profile of the organization responsible for the processes involved in the product life cycle, (ii) definition of the basic requirement to assess each subcategory, (iii) definition of levels based on the environment context or organizational practice and the data availability and (iv) assignment of a quantitative value. The result of the method applied was the development of the subcategory assessment method (SAM). SAM is a characterization model that evaluates subcategories during the impact assessment phase. This method is based on the behaviour of organizations responsible for the processes along the product life cycle, thereby enabling a social performance evaluation. The method, thus, presents levels for each subcategory assessment. Level A indicates that the organization exhibits proactive behaviour by promoting basic requirement (BR) practices along the value chain. Level B means that the organization fulfils the BR. Levels C and D are assigned to organizations that do not meet the BR and are differentiated by their context. The greatest difficulty when developing SAM was the definition of the BR to be used in the evaluation of the subcategories, though many indications were present in the methodological sheets. SAM makes it possible to go from inventory to subcategory assessment. The method supports evaluation across life cycle products, thereby ensuring a more objective evaluation of the social behaviour of organizations and applicable in different countries. When using SAM, it is advisable to update the data for the context environment. The method might be improved by using data for the social context that would consider not only the country, but also the region, sector and product concerned. A further improvement could be a subdivision of the levels to better encompass differences between organizations. It is advisable to test SAM by applying it to a case study.

Global guidance on environmental life cycle impact assessment indicators: findings of the scoping phase

Abstract: Olivier Jolliet & Rolf Frischknecht & Jane Bare & Anne-Marie Boulay & Cecile Bulle & Peter Fantke & Shabbir Gheewala & Michael Hauschild & Norihiro Itsubo & Manuele Margni & Thomas E. McKone & Llorenc Mila y Canals & Leo Postuma & Valentina Prado-Lopez & Brad Ridoutt & Guido Sonnemann & Ralph K. Rosenbaum & Tom Seager & Jaap Struijs & Rosalie van Zelm & Bruce Vigon & Annie Weisbrod & with contributions of the other workshop participants

Life cycle assessment of vegetable products: a review focusing on cropping systems diversity and the estimation of field emissions

Abstract: Recent life cycle assessment studies for vegetable products have identified the agricultural stage as one of the most important contributors to the environmental impacts for these products, while vegetable production systems are characterized by specific but also widely diverse production conditions. In this context, a review aiming at comparing the potential impacts of vegetable products and analyzing the relevance of the methods and data used for the inventory of the farm stage appeared necessary. Ten papers published in peer-reviewed scientific journals or ISO-compliant reports were selected. First, a presentation of the selected papers was done to compare the goal and scope and the life cycle inventory data to the related sections in the ILCD Handbook. Second, a quantitative review of input flows and life cycle impact assessment (LCIA) results (global warming, eutrophication, and acidification) was based on a cropping system typology and on a classification per product group. Third, an in-depth analysis of the methods used to estimate field emissions of reactive nitrogen was proposed. The heated greenhouse system types showed the greatest global warming potential. The giant bean group showed the greatest acidification and eutrophication potentials per kilogram of product, while the tomato group showed the greatest acidification and eutrophication potentials per unit of area. Main sources of variations for impacts across systems were yields and inputs variations and system expansion rules. Overall, the ability to compare the environmental impact for these diverse vegetable products from cradle-to-harvest was hampered by (1) weaknesses regarding transparency of goal and scope, (2) a lack of representativeness and completeness of data used for the field stage, and (3) heterogeneous and inadequate methods for estimating field emissions. In particular, methods to estimate reactive nitrogen emissions were applied beyond their validity domain. This first attempt at comparing the potential impacts of vegetable products pinpointed several gaps in terms of data and methods to reach representative LCIA results for the field production stage. To better account for the specificities of vegetable cropping systems and improve the overall quality of their LCA studies, our key recommendations were (1) to include systematically phosphorus, water, and pesticide fluxes and characterize associated impacts, such as eutrophication, toxicity, and water deprivation; (2) to better address space and time representativeness for field stage inventory data through better sampling procedures and reporting transparency; and (3) to use best available methods and when possible more mechanistic tools for estimating Nr emissions.

Material flow analysis and energy requirements of mobile phone material recovery processes

Abstract: Proper recycling of mobile phones and other electronic products is important in order to reduce the generation of large amounts of hazardous waste, lessen environmental and social problems associated to the extraction of minerals and primary production of materials, and also minimize the depletion of scarce materials that are often difficult to substitute. Current material recovery processes are used to recycle electronic waste of various compositions. Based on a review of the recycling processes and material flow analysis (MFA), we attribute the material and energy required to recover metals from 1 tonne of discarded mobile phones. We estimate that the recovery rates of gold, palladium, silver, copper, nickel, lead, antimony, and tin from the recycling processes described are 80 to 99 % (16.4 % of the phone in weight). The two main industrial processes used at present time (pyrometallurgical and combined pyro-hydrometallurgical) have similar energy consumptions (7,763 and 7,568 MJ/tonne of mobile phones, respectively). An average tonne of used mobile phones represents a potential of 128 kg of copper, 0.347 kg of gold, 0.15 kg of palladium, 3.63 kg of silver, 15 kg of nickel, 6 kg of lead, 1 kg of antimony, and 10 kg of tin as well as other metals that are not yet profitable to recover but might be in the future. We find that the energy consumed to recover copper from mobile phones is half of that needed for copper primary extraction and similar or greater energy savings for precious metal refining. Nevertheless, only 2.5 % of mobile phones arrive to industrial recovery facilities. There is a great potential to increase the amount of metals being recovered, thereby reducing energy consumption and increasing resource efficiency.

Life cycle assessment as a decision support tool for bridge procurement: environmental impact comparison among five bridge designs

Abstract: The conventional decision-making for bridges is mostly focusing on technical, economical, and safety perspectives. Nowadays, the society devotes an ever-increased effort to the construction sector regarding their environmental performance. However, considering the complexity of the environmental problems and the diverse character of bridges, the related research for bridge as a whole system is very rare. Most existing studies were only conducted for a single indicator, part of the structure components, or a specific life stage. Life Cycle Assessment (LCA) is an internationally standardized method for quantifying the environmental impact of a product, asset, or service throughout its whole life cycle. However, in the construction sector, LCA is usually applied in the procurement of buildings, but not bridges as yet. This paper presents a comprehensive LCA framework for road bridges, complied with LCA ReCiPe (H) methodology. The framework enables identification of the key structural components and life cycle stages of bridges, followed by aggregation of the environmental impacts into monetary values. The utility of the framework is illustrated by a practical case study comparing five designs for the Karlsnas Bridge in Sweden, which is currently under construction. This paper comprehensively analyzed 20 types of environmental indicators among five proposed bridge designs, which remedies the absence of full spectrum of environmental indicators in the current state of the art. The results show that the monetary weighting system and uncertainties in key variables such as the steel recycling rate and cement content may highly affect the LCA outcome. The materials, structural elements, and overall designs also have varying influences in different impact categories. The result can be largely affected by the system boundaries, surrounding environment, input uncertainties, considered impact indicators, and the weighting systems applied; thus, no general conclusions can be drawn without specifying such issues. Robustly evaluating and ranking the environmental impact of various bridge designs is far from straightforward. This paper is an important attempt to evaluate various designs from full dimensions. The results show that the indicators and weighting systems must be clearly specified to be applicable in a transparent procurement. This paper provides vital knowledge guiding the decision maker to select the most LCA-feasible proposal and mitigate the environmental burden in the early stage.

Utilization of recovered wood in cascades versus utilization of primary wood—a comparison with life cycle assessment using system expansion

Abstract: A cascading utilization of resources is encouraged especially by legislative bodies. However, only few consecutive assessments of the environmental impacts of cascading are available. This study provides answers to the following questions for using recovered wood as a secondary resource: (1) Does cascading decrease impacts on the environment compared to the use of primary wood resources? (2) What aspects of the cascading system are decisive for the life cycle assessment (LCA) results? We conducted full LCAs for cascading utilization options of waste wood and compared the results to functionally equivalent products from primary wood, thereby focusing on the direct effects cascading has on the environmental impacts of the systems. In order to compare waste wood cascading to the use of primary wood with LCA, a functional equivalence of the systems has to be achieved. We applied a system expansion approach, considering different options for providing the additionally needed energy for the cascading system. We found that the cascading systems create fewer environmental impacts than the primary wood systems, if system expansion is based on wood energy. The most noticeable advantages were detected for the impact categories of land transformation and occupation and the demand of primary energy from renewable sources. The results of the sensitivity analyses indicate that the advantage of the cascading system is robust against the majority of considered factors. Efficiency and the method of incineration at the end of life do influence the results. To maximize the benefits and minimize the associated environmental impacts, cascading proves to be a preferable option of utilizing untreated waste wood.

The ESPA (Enhanced Structural Path Analysis) method: a solution to an implementation challenge for dynamic life cycle assessment studies

Abstract: Purpose By analyzing the latest developments in the dynamic life cycle assessment (DLCA) methodology, we identify an implementation challenge with the management of new temporal information to describe each system we might want to model. To address this problem, we propose a new method to differentiate elementary and process flows on a temporal level, and explain how it can generate temporally differentiated life cycle inventories (LCI), which are necessary inputs for dynamic impact assessment methods.