Simplified Life Cycle Assessment Approaches and Potential Impact Shifts
Sammanfattning: Road transport contributes to approximately one quarter of all EU greenhouse gas emissions and is the leading cause of air pollution in cities. There are significant measures aimed at the reduction of use phase environmental impacts; in the EU, these strategies focus on the decarbonisation of road transport, such as through the prioritization of low- and zero-emission vehicles. Electric vehicles are seen as one of the primary measures for reducing road transport impacts. However, the introduction of new technology includes new challenges throughout the vehicle life cycle, such as the need for critical raw materials, high-energy manufacturing, charging electricity, and waste management; this, in turn, leads to a risk of impact shifts between life cycle phases and impact categories.Life Cycle Assessment (LCA) is one way to analyse environmental impacts. Applying LCA and life cycle thinking in research and industry allows for the detection of impact shifts and environmental sub-optimisation. A full LCA study is demanding in terms of both data collection efforts and user expertise requirements. The need to simplify the process and results of an assessment in order to support decision-making was identified in the early days of LCA development.There are numerous simplification approaches in LCA. Previously, the most prominent simplification terms were screening and streamlined LCA; now, a multitude of names and approaches have emerged. There is no consensus in the LCA community about LCA simplifications. In some cases, the line between what should be considered an LCA, simplified LCA or neither is fuzzy. The haphazard application of simplifications in LCA studies undermines the transparency and confidence in results.The aim of this thesis is to use the life cycle perspective guided by simplified LCA approaches to increase our understanding of the risk of impact shifts, resulting from measures to reduce vehicle environmental impacts. Four appended publications present five LCA studies of road vehicles. All appended studies are simplified using different approaches. The studies examine different impact reduction measures such as changing drivetrains, reducing particulate emissions from braking, and the scrapping of old vehicles. A fifth publication is a literature review that explores the common understanding of simplifications used in published LCA studies. The review identifies and investigates the types of simplifications used and discusses how these might be categorised.The appended LCA studies examine both impact shifts from one life cycle phase to another and between impact categories. It is difficult to determine whether a decrease in a life cycle phase or impact category could offset an increase in another and, therefore, to be able to determine if an impact shift is an acceptable compromise. New smart materials are expected to solve many environmental impact issues; however, there are risks associated with insufficient life cycle inventory data, limitations in knowledge about potential environmental impacts, and inefficient regulations covering new materials.The analysis of simplification approaches and case studies indicates that most simplifications are motivated by the lack of primary data. Additionally, study findings strengthen concerns about the significant inconsistency in LCA simplification terminology and how well approaches are described in individual studies. There is a need for a common simplification terminology and reporting standard. Due to the wide variety of purposes, scenarios, and products assessed, it is impossible to devise a one-size-fits-all approach for simplifications, especially if the aim is to identify potential impact shifts.
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