Development of life cycle assessment methodology: a focus on co-product allocation

Life Cycle Assessment (LCA) is a developing tool that can assist decision-makers in evaluating the comparative potential cradle-to-grave, environmental impacts of their actions in order to prevent unintended consequences. The LCA tool is designed to assist in the evaluation along the ‘value chain’ of a product’s life from the perspective that the many processes are interdependent, so that decisions made at one point along the life cycle can have consequences elsewhere. LCA enables the estimation of the cumulative environmental impacts, often including impacts that go beyond the boundaries of traditional analyses. By including the impacts throughout the product life cycle, LCA provides a comprehensive view of the environmental aspects and a more accurate picture of the true environmental trade-offs in product or process alteration or selection. After a brief look at the general LCA methodology, this thesis presents information about some of the current! limitations that prevent LCA from being a more widely-used tool that generates replicable, defensible results. The thesis author then introduces the subject of integrating LCA results into the decision-making process, suggesting that the potentially, holistic view offered by LCA can be valuable as one tool for helping to achieve sustainable societal development. Bio-fuels are presented as the subject of a “wicked problem” for which LCA can be used to support the decision-making process. The thesis then focuses on the co-product allocation issue and presents the results of testing various allocation schemes (weight, volume, market value, energy, and demand-based approach) across a fuel system. The relative ranking of conventional gas to alternative ethanol fuels is consistent in all allocation schemes. This thesis addresses three topical areas within LCA: the evolution and current status of LCA methodology (Chapter 2), integrating LCA with sustainability decision-making! with a focus on bio-based materials (Chapter 3), and co-product allocation methodology (Chapters 4 and 5). The final chapter (Chapter 6) presents overall conclusions about the future of LCA and suggests further, urgently needed, research.