AbstractsEngineering

Life-Cycle Assessment (LCA) covers a set of tools and techniques that aim to estimate the environmental impacts generated by a product or service all along its life-cycle including: rawmaterial extraction, production steps, transportation, use phase and end-of-life scenarios.The Life-Cycle Inventory (LCI) is a key step in LCA. It focuses on quantifying all physicaland/or monetary flows involved in the life-cycle of the product/service considered. Theseflows are named as ‘elementary flows’ in ISO terms. After having dealt with the main issuesof the ‘Goal and Scope definition’ step, that is giving a clear definition of the ‘functional unit’to consider, setting clear boundaries between elements to count in and those to disregard,practitioners need a coherent framework to quantify elementary flows and estimate missingelements. Several methodologies have been developed, each of them with both clearadvantages but also distinct disadvantages, depending on the purpose of the study: processbasedmethods, Input-Output based methods (IO-based methods), and also hybrid methods.In 2004, Suh suggested a method known as IHA (Integrated Hybrid Analysis) that appears towipe out the strict boundary between process-based and IO-based methods, taking advantagesof both methods as complementarities. Previous hybrid models were found incompleteregarding end-of-life scenario, especially with open-loop recycling.However, Suh admits that there remain several drawbacks in the IHA model, such as thetreatment of international trade and flows of products and services. They are usuallyconsidered as a single, homogeneous commodity despite their huge variety. This is apersistent limitation, already known by process-based and IO-based LCA practitioners. In aglobalized economy, where most products are manufactured in one place and consumed onthe other side of the world, this serious limitation cannot hold any longer.In this thesis, a review of both process-based, IO-based and hybrid methods for LCI ispresented, in terms of principles, advantages and limitations. It is followed by an explanationand demonstration of the mathematics underpinning the IHA model. Then, a model isproposed that would enable the model to take international trade into account. This is enabledthanks to the inspiration provided by a multi-regional framework proposed for ecologicalfootprint calculation. A numerical example supports this suggestion.The outcomes of this improved model are thought to go beyond its initial aims: the multiregionalIHA model could act as a variable geometry model where strongly affected regionsare efficiently focused on, without disregarding the others. This could prove efficient inavoiding side-effects of policy-making. Also, it would enable the development of moreregion-specific environmental impact coefficients, thus putting less pressure on fragileecosystems. The IHA model is a robust model: it is simple to handle – provided a userfriendlyinterface exists – but with a complex and evolutionary engine. It is compatible withan iterative progress in…