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International audience; PurposeInformation and communications technology (ICT) plays a key role in higher education in improving the teaching process. Consequently, the environmental impacts associated with ICT are increasing, and innovative solutions must be deployed to reduce these impacts and increase students’ awareness. Single-board computers (SBCs) are promising because they rely on less materials and energy than desktop computers (PCs). But additional servers are required to perform large-scale computations. Hence, this paper aims at conducting comparative LCA between SBCs and PCs.Materials and methodsThe study is conducted in the context of a French engineering school with the following functional unit: “use 600 computers for 5 years in an engineering school.” Two scenarios are defined to fulfil this functional unit. Scenario 1 is the use of 600 PCs (current infrastructure), and scenario 2 is the use of 600 SBCs combined with 6 servers (alternative infrastructure). The analysis includes the materials manufacturing, assembly, packaging, transport, use and end-of-life of each device. Life cycle inventory (LCI) of the foreground systems was generated using a variety of sources: disassembly of computers, counting of electronic components, datasheets, estimations, etc. LCI of the background systems is taken from ecoinvent 3.5. The selected life cycle impact assessment methodology is ReCiPe 2016 midpoint, and computation of impacts is done with openLCA 1.10.3.Results and discussionScenario 2 (SBCs + servers) generates 84 to 92% less impact than scenario 1 (PCs) in all categories. In terms of global warming, scenarios 1 and 2 generate 225 and 18 tCO2 eq per functional unit, respectively. This is explained by the large reduction in material and energy requirements for SBCs which is not counterbalanced by the servers. Equipment manufacturing accounts for the largest share of impacts in most categories for both scenarios (e.g., ~70% for global warming), followed by the use phase. This differs from the results found in the literature, as this study was conducted in the context of France, which has a low-carbon electricity mix.ConclusionsOur analysis has shown that SBCs combined with servers reduce the carbon footprint and other environmental impacts of ICT infrastructure for higher education. This study provides an example of low tech-oriented solution for students. Other prospective solutions (e.g., use of laptops) should be extensively studied in the future. From an LCA point of view, updating the inventory data related to background processes for electronic components is a necessary step forward to improve the certainty of the results.

How to apply allocation in an life cycle assessment (LCA) is a long-running and controversial debate. Consensus seems to exist on the fact that the allocation procedure should follow logically from the LCA goal definition. This paper proposes to use an axiomatic method to (1) identify an allocation procedure for co-production, joint treatment, and recycling, that best responds to a specific LCA goal and (2) communicate the rationale applied by the LCA practitioner transparently. The method is illustrated via a case study. The specific goal definition for which a suitable allocation procedure is identified is to evaluate what impacts can be attributed to a product, which could inform a company about potential sources of reputation damage. Subjective assumptions that reflect our vision of “what impacts can be attributed to a product” are described in definitions and axioms. Axioms are formulated that describe the system boundaries of the product system and the partitioning criterion. The derived allocation procedure corresponds to “Allocation at the Point of Substitution,” which is applied in one of the system models of ecoinvent. Partitioning is based on market information, which corresponds to a cause-oriented perspective on “what impacts can be attributed to a product.” Other LCA goal definitions and rationales could require different system boundaries or a different partitioning criterion. The axiomatic method presented in this paper supports the identification of a suitable allocation procedure for a defined LCA goal and the transparent communication of the rationale that backs up this procedure. Building forth on the approach of this paper, a collection of axioms and corresponding allocation procedures could be developed on which consensus might exist within the LCA community. Such goal-dependent allocation procedures could form the basis of future guidance on LCA.

Partitioning is often recommended as allocation procedure in attributional Life Cycle Assessments (a-LCAs). However, little guidance is available on how to apply partitioning to recycled products. This paper aims to demonstrate and discuss the application of the allocation procedure allocation at the point of substitution (APOS) via an evaluation of the impacts of the recycled phosphor yttrium europium oxide (YOX) from end-of-life fluorescent lamps. Starting from a multifunctional recycling process, APOS is applied by (1) identifying the products of the foreground sub-system, (2) identifying the origin of the recycled waste, (3) defining the boundaries of the production systems, and (4) applying economic allocation. It appears that recycled YOX is accountable for lower impacts than primary YOX for most impact categories. The largest contributor to the impacts of recycled YOX are the impacts related to the primary production of the fluorescent lamp, such as the use of mercury in the lamp tube. Even if this can be counter-intuitive to accept—as these impacts seem unrelated to YOX—these results provide useful information on whether the supply route of rare earth elements (REEs) from end-of-life fluorescent lamps is “future proof,” regarding potential (supply) risks due to environmental impacts upstream in the product supply chain. The application of APOS is demonstrated on the end-of-life recycling of rare earth elements. APOS provides the user of the recycled REE information about environmental impacts upstream in the product’s value chain. This could inform about the sustainability of the company’s operations—i.e., whether the future use or production of a material might be compromised due to (regulations to decrease) environmental impacts.

This article presents an approach to integrating life cycle assessment (LCA) into an activity‐based costing (ABC) model to develop a steering system that takes into account both financial costs and associated environmental impacts. By combining the formalism of LCA and ABC matrix calculations, we show how impact assessment results can be affiliated with costs to jointly and simultaneously compute the costs and environmental impacts of products and activities. The conditions of integration are developed following the four‐step structure of LCA. The proposal is applied to a simplified case study of the ‘Classic Pen Company.’ The developed ABC‐LCA approach paves the way for further test applications, which are considered useful in the context of environmental indicators for strategic steering, communication with customers and forecasting or simulation.

The space sector is a new area of development for Life Cycle Assessment (LCA) studies. However, it deals with strong particularities which complicate the use of LCA. One of the most important is that the space industry is the only human activity crossing all stages of the atmosphere during the launch event or the atmospheric re-entry. As a result, interactions occur not only with the natural environment but also with the orbital environment during the use phase and the end-of-life of space missions. In this context, there is a lack of indicators and methods to characterise the complete life-cycle of space systems including their impact on the orbital environment. The end-of-life of spacecraft is of particular concern: space debris proliferation is today a concrete threat for all space activities. Therefore, the proposed work aims at characterising the orbital environment in term of space debris crossing the orbital resource. A complete methodology and a set of characterisation factors at midpoint level are provided. They are based on two factors: (i) the exposure to space debris in a given orbit and (ii) the severity of a potential spacecraft break-up leading to the release of new debris in the orbital environment. Then, we demonstrate the feasibility of such approach through three theoretical post-mission disposal scenarios based on the Sentinel-1A mission parameters. The results are discussed against the propellant consumption needed in each case with the purpose of addressing potential 'burden shifting' that could occur between the Earth environment and the orbital one.

The built environment is recognized as a major hotspot of resource use and environmental impacts. Life Cycle Assessment (LCA) has been increasingly used to assess the environmental impacts of construction products and buildings and a new trend is characterized by the application of LCA to larger systems such as neighborhoods during early design phases. Assessing urban development projects at the master-planning stage raises the issue of inventory data collection, especially for building materials which are reported to account for about 20% of primary energy consumption in buildings, and up to 45% of associated greenhouse gas emissions. Urban planners focus on the urban morphology and little information is known about the buildings characteristics apart from their general shape. This paper proposes a simplified model for the assessment of buildings embodied energy and embodied carbon in relation with urban planners’ design levers. The model relies on the decomposition of buildings into functional elements in order to be sensitive to the shape of the buildings. A detailed sensitivity analysis and contribution analysis of the model is conducted on two types of generic building forms, in order to investigate the influence of parameters relating to shape on the embodied energy and embodied carbon of a building. The sensitivity analysis shows that the parameters relating to shape (such as the dimension of the buildings) are more influential on the embodied energy and embodied carbon per square meter of building than the ones relating to the elements themselves (such as the wall thickness). The contribution analysis also brings evidence of the relation between the compactness factor and the embodied energy and embodied carbon of a building.

Multifunctionality in life-cycle assessment (LCA) is solved with allocation, for which many different procedures are available. Lack of sufficient guidance and difficulties to identify the correct allocation approach cause a large number of combinations of methods to exist in scientific literature. This paper reviews allocation procedures for recycling situations, with the aim to identify a systematic approach to apply allocation. Assumptions and definitions for the most important terms related to multifunctionality and recycling in LCA are given. The most relevant allocation procedures are identified from literature. These procedures are expressed in mathematical formulas and schemes and arranged in a systematic framework based on the underlying objectives and assumptions of the procedures. If the LCA goal asks for an attributional approach, multifunctionality can be solved by applying system expansion—i.e. including the co-functions in the functional unit—or partitioning. The cut-off approach is a form of partitioning, attributing all the impacts to the functional unit. If the LCA goal asks for a consequential approach, substitution is applied, for which three methods are identified: the end-of-life recycling method and the waste mining method, which are combined in the 50/50 method. We propose to merge these methods in a new formula: the market price-based substitution method. The inclusion of economic values and maintaining a strict separation between attributional and consequential LCA are considered to increase realism and consistency of the LCA method. We identified the most pertinent allocation procedures—for recycling as well as co-production and energy recovery—and expressed them in mathematical formulas and schemes. Based on the underlying objectives of the allocation procedures, we positioned them in a systematic and consistent framework, relating the procedures to the LCA goal definition and an attributional or consequential approach. We identified a new substitution method that replaces the three existing methods in consequential LCA. Further research should test the validity of the systematic framework and the market price-based substitution method by means of case studies.

Multifunctionality in LCA can be solved by several allocation procedures. Various official guidelines give divergent recommendations in which allocation procedure to apply, and up to now, no consensus has been reached. We aim to identify the obstacles to a consistent allocation approach that can be applied to all product categories and is supported by a broad range of stakeholders. Based on a systematic framework for consistent allocation, developed by Schrijvers et al. (Int J Life Cycle Assess, 2016), we identify five review criteria that indicate the degree of consistency in the proposed allocation procedure of official guidelines. Several relevant guidelines, i.e. ISO 14044, ISO/TR 14049, ISO/TS 14067, the ILCD Handbook, BP X30-323-0, PAS 2050, the Greenhouse Gas Protocol, EN15804, PEF Guide and guidance documents for EPDs and PCRs, are reviewed according to these criteria. None of the investigated guidelines fully follows the systematic framework for allocation. Often, different approaches are recommended for co-products and recycled materials, although the boundary between these flows is not always clear. Many guidelines do not recognize the existence of different LCA goals; therefore, elements of attributional and consequential LCAs are often mixed. The market situation of the recycled material is not always taken into account, e.g. in the mandatory 50/50 method of the PEF Guide. The ILCD Handbook and the General Programme Instructions for the International EPD® System provide most consistent guidance. We argue that consistency does not require a one-formula-fits-all method, as this would favour some product categories and only responds to a certain LCA goal. A critical review of guidelines against a systematic framework for allocation of co-products and recycled materials shows that few guidelines propose a consistent allocation approach. The main obstacles for consistency are the different approaches for co-production and (different types of open-loop) recycling and disregarding of different LCA goals and recycled material markets. We recommend to include material specific guidance in Product Category Rules on the determination of market prices, quality determining factors and relevant material properties for different applications.

International audience; The emphasis on the sustainable urban water management has increased over the last decades. In this context decision makers need tools to measure and improve the environmental performance of urban water systems (UWS) and their related scenarios. In this paper, we propose a versatile model, named WaLA (Water system Life cycle Assessment), which reduces the complexity of the UWS while ensuring a good representation of water issues and fulfilling life cycle assessment (LCA) requirements. Indeed, LCAs require building UWS models, which can be tedious if several scenarios are to be compared. The WaLA model is based on a framework that uses a 'generic component' representing alternately water technology units and water users, with their associated water flows, and the associated impacts due to water deprivation, emissions, operation and infrastructure. UWS scenarios can be built by inter-operating and connecting the technologies and users components in a modular and integrated way. The model calculates life cycle impacts at a monthly temporal resolution for a set of services provided to users, as defined by the scenario. It also provides the ratio of impacts to amount of services provided and useful information for UWS diagnosis or comparison of different scenarios. The model is implemented in a Matlab/Simulink interface thanks to object-oriented programming. The applicability of the model is demonstrated using a virtual case study based on available life cycle inventory data.

International audience; Water is a growing concern in cities, and its sustainable management is very complex. Life cycle assessment (LCA) has been increasingly used to assess the environmental impacts of water technologies during the last 20 years. This review aims at compiling all LCA papers related to water technologies, out of which 18 LCA studies deals with whole urban water systems (UWS). A focus is carried out on these 18 case studies which are analyzed ac- cording to criteria derived from the four phases of LCA international standards. The results show that whereas the case studies share a common goal, i.e., providing quantitative in- formation to policy makers on the environmental impacts of urban water systems and their forecasting scenarios, they are based on different scopes, resulting in the selection of different functional units and system boundaries. A quantitative comparison of life cycle inventory and life cycle impact assessment data is provided, and the results are discussed. It shows the superiority of information offered by multi-criteria approaches for decision making compared to that derived from mono-criterion. From this review, recommenda- tions on the way to conduct the environmental assessment of urban water systems are given, e.g., the need to provide consistent mass balances in terms of emissions and water flows. Remaining challenges for urban water system LCAs are identified, such as a better consideration of water users and resources and the inclusion of recent LCA developments (territorial approaches and water-related impacts).; L'eau est une préoccupation croissante dans les villes, et sa gestion durable est très complexe. L'analyse du cycle de vie (ACV) a été de plus en plus utilisé pour évaluer les impacts environnementaux des technologies de l'eau au cours des 20 dernières années. Cet examen vise à compiler tous les documents de l'ACV liés aux technologies de l'eau, dont 18 études ACV traite des systèmes d'eau urbains entiers (UWS). Une mise au point est effectuée sur ces 18 études de cas qui sont analysés selon des critères issus des quatre phases de normes internationales ACV. Les résultats montrent que, tandis que les études de cas partagent un objectif commun, à savoir, fourniture d'informations quantitatives pour les décideurs politiques sur les impacts environnementaux des systèmes d'eau urbains et leurs scénarios de prévision, ils sont basés sur des portées différentes, ce qui entraîne la sélection des différents fonctionnelle unités et les limites du système. Une comparaison quantitative de l'inventaire du cycle de vie et du cycle de vie des données d'évaluation d'impact est fourni, et les résultats sont discutés. Il montre la supériorité de l'information offerte par les approches multi-critères pour la prise de décision par rapport aux informations provenant de mono-critère. De cet examen, des recommandations sur la façon de procéder à l'évaluation environnementale des systèmes d'eau urbains sont donnés, par exemple, la nécessité de fournir des bilans de masse cohérentes en termes d'émissions et des flux d'eau. Défis à relever pour le système des eaux urbaines ACV sont identifiés, comme une meilleure prise en compte des utilisateurs et des ressources en eau et l'inclusion de l'évolution récente de l'ACV (approches territoriales et les impacts liés à l'eau).