Towards improved life cycle assessment of environmental systems: geographical perspectives on multi-scale challenges in the context of bioenergy feedstock production

Abstract

Accurate environmental assessments can help inform landowners, policy-makers, and energy consumers about the risks or benefits of using biomass production for energy over other land-use options such as other renewable energy projects or food production. Life cycle assessment (LCA), a tool often used to assess the potential environmental impacts of bioenergy systems, faces ongoing issues associated with evaluating dynamic multi-scale systems. Although the importance of considering site-specific variation in LCA as geographies change has been identified for some time, adoption of geographical concepts in LCA has been slow to develop. The aim of this thesis is to facilitate a discussion between geographic and LCA thought, and address what LCA approaches should look like when we need to evaluate environmental systems across a range of geographies, in the context of bioenergy feedstock production. An in-depth analysis of existing LCA standards reveal several areas in goal and scope directions where vague or absent instructions may lead to inappropriate use of geographical attributes by practitioners. Using gaps identified in LCA standards, a systematic review of bioenergy LCA literature is performed over a ten-year period (2005 – 2015) to understand how spatial and temporal attributes of systems, input data, and scope definitions vary and may affect results when different LCAs are compared. Finally, using a modular multi-scale approach, a LCA of short-rotation coppice (SRC) willow is performed for a site in Guelph, Ontario, to evaluate modified LCA performance that incorporates geographic inputs over more traditional approaches to compiling inventories and evaluating impacts. The inclusion of smaller scale spatial and temporal attributes in the modular approach showed that improving data resolution can be used to address site-specific questions that more aggregated data cannot. This thesis points towards a need to address issues of scale within LCA standards, particularly with respect to components of the scope such as data quality requirements. Improving the transparency of geographical attributes of future LCAs provide an opportunity to document underlying characteristics of systems that may otherwise go unnoticed, but also provide a framework in which future dynamic LCA tools and models can be integrated.