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International audience

International audience; Water utilities draw different water sources (surface and groundwater), including increased use of alternative sources (e.g. desalinated water, reused water, inter-basin water transfers) to supply freshwater to different users (domestic, agriculture, etc.). The combination of water sources and technologies (including infrastructures and energy) results in a regional water supply mix (WSmix) for each specific use. Existing Life Cycle Inventory (LCI) databases used in Life Cycle Assessment (LCA), do not include these mixes when modelling processes, leading to a poor representation of water supply systems and related environmental impacts. To fill this gap, this paper proposes a consistent framework for modelling a regional WSmix at worldwide scale. The WSmix framework includes the scope and system boundaries definition as well as a standardisation of terminology and classification of water sources and users. To facilitate implementation of theWSmix, this paper provides a worldwide database of water source mixes per user and a technology matrix linking water sources to water production technologies, including the connection with the local electricity mix. The relevance of including the WSmix in LCI databases for proper water-use impact assessment is demonstrated with an illustrative case study. The paper finally concludes on the need of using the regionalized WSmix in routine LCA, which is just as straightforward as the use of the regionalized electricity supply mix. Besides, the developed WSmix provides interesting insights beyond the LCA scope to support the strategic management of water sources at various scales including the global scale.

International audience

Life cycle assessment and carbon footprint are regularly applied in different sectors of the process industry. There is a growing need to integrate different sustainability aspects as part of daily decision-making, but this requires further development of the assessment methods and related tools, together with effective means for communication and visualisation of the results. Currently, life cycle based methods are applied in many different contexts, and the results need to be communicated to both internal and external stakeholders, many of whom are not experts in life cycle assessment. The paper discusses challenges faced by industrial sustainability experts and practitioners when communicating and visualising LCA results in different decision-making contexts. Specific challenges include (among others) communicating uncertainty, explaining the proximate and underlying causes of variability in results, integrating results representing different impact categories and defining proper benchmarks for comparison. Challenges related to interpretation and communication are faced especially in situations in which a decrease in one indicator or impact category is offset with an increase in another category. Ideally, the results should be presented and visualised in ways that are easy to understand, even though the underlying assumptions would be complex. The paper is based on the results of the SAMT (Sustainability assessment methods and tools to support decision-making in the process industries) project, focusing on communication of LCA results in different decision-making contexts. During the project, experiences and good practices from the cement, oil, metal, water, waste and chemical industry were collected using interviews, workshops and practical case studies. The findings of the project indicate that many of the challenges related to communication are similar despite of the sector in question. There is also a need to harmonise the way results are presented, in order to increase transparency and improve comparability of the studies. Ability to create meaningful and easily understandable results would be essential in order to increase the acceptability and applicability of the methods, and to mainstream their use in different decision-making situations, that may include for example product and process development, supply chain management, investment decisions, marketing and responding to stakeholder requests. The findings of the project are complemented with examples of good practices and successful case studies from the chemical, water and oil sectors.