Avancées méthodologiques et applications de l’analyse du cycle de vie : du micro-usinage aux panneaux photovoltaïques

Abstract

The objective of this thesis is to explore two related systems by studying their impacts from a micro and macro perspective. To this end, two different methods of Life Cycle Assessment (LCA) and associated practices are used. Two studies were conducted, one published as a conference paper and one submitted as a journal article, to explore the micro aspect, via the implementation of an LCA on the one hand, to study the environmental impacts of a glass micro-machining method. On the other hand, to explore the macro aspect, via a prospective LCA, and partially consequential LCA, which was carried out on the study of the early replacement of PV panels. These two articles show, that the micro analysis, via the attributional LCA, yielded some unexpected results : electricity consumption is almost negligible, while the computer screen used is the largest contributor to the impact on climate change. It should also be noted that consumables are not negligible and that lifespan has a fairly significant impact, despite some limitations. Meanwhile, the macro study, using prospective and consequential LCA, required more layers of modeling (modeling of marginal suppliers and the amount of electricity displaced, reuse of components), thus adding uncertainty. It was thus shown that : the reuse of components is always beneficial but to varying degrees depending on the impact methods used, and that the impacts avoided by early replacement depend on many parameters (including the impact methods), but are positive (or zero) on average, although there are a number of cases in which the impacts are rather negative. Thus, the two studies explored the importance of the electricity mix, lifespan, and even the systemic approach in processes and in the field of LCA in general. This thesis has thus explored two systems at two different scales using different LCA methods, examining their practices as well as their limitations and uncertainties. It shows that LCA is a very important tool for assessing environmental impacts, enabling the study of systems at very different scales and in very different contexts.

Date	4 Nov 2025
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Andrew Henderson (Supervisor) & Lucas Hof (Co-supervisor)