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Life cycle assessment of transport systems and transport infrastructure

Investigating methodological approaches and quantifying impacts at project and network levels

Time: Tue 2021-04-06 14.00

Location: Videolänk -, Du som saknar dator /datorvana kontakta Anna Björklund / Use the e-mail address if you need technical assistance, Stockholm (English)

Subject area: Planning and Decision Analysis, Strategies for sustainable development

Doctoral student: Carolina Liljenström , Hållbarhet, utvärdering och styrning

Opponent: Professor Rolf André Bohne, Norwegian University of Science and Technology

Supervisor: Docent Anna Björklund, Hållbarhet, utvärdering och styrning; PhD Susanna Toller, Hållbarhet, utvärdering och styrning, Trafikverket

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Reducing greenhouse gas emissions from the transport sector is a key challenge to reach global climate targets and limit global warming to below 2 ºC. The use of life cycle assessment (LCA) may provide knowledge about the environmental impacts of transport systems so that emission reduction measures can be identified.

The aim of this thesis is to investigate how LCA can contribute with knowledge that can be used to support specific decisions in the context of transport system policy and planning, to demonstrate how LCA can be conducted at project and network levels, and to contribute with knowledge of direct and indirect climate impact and primary energy use of the Swedish transport infrastructure and the Swedish transport system at a network level.

The thesis includes four papers that contribute to achieving this aim. Paper 1 demonstrates an approach for the identification of hotspots in Swedish road, rail, air, and sea transport infrastructure at a network level. Paper 2 demonstrates this approach for the full transport system at a network level, including national and international freight transport and passenger travel by road, rail, air, and sea. At the project level, Paper 3 investigates how LCA can be used as decision-support in choice of road corridor, considering prerequisites of data availability and usefulness of results for decision-making. Paper 4 maps approaches used to quantify impacts of the maintenance stage in 92 project-level LCAs of road and rail infrastructure and discusses their applicability in policy and procurement.

Paper 1 estimated that the annual climate impact of Swedish transport infrastructure is about 3 Mtonne CO2 equivalents and that the corresponding primary energy use is about 27 TWh. Road and rail infrastructure contributed to 90% of these impacts. Additional hotspots identified were reinvestment of roads and railways and production of asphalt, concrete, and steel. Paper 2 estimated that the annual climate impact of the Swedish transport system is about 40 Mtonne CO2 equivalents and that the corresponding primary energy use is about 196 TWh. Road transport and aviation together accounted for 85% of these impacts. Indirect impacts were significant, accounting for about a third of the impacts. The main causes of indirect impacts were fuel production for road passenger travel and manufacturing of passenger cars.

Paper 3 found that LCA-based models used in early planning should include generic data that are nation specific (preferably approved by the national road authority) and that can be replaced by project specific data when needed. Further, both traffic and infrastructure should be included at a level of detail that allows the identification of improvement measures and the assessment of uncertainty in the results. Results should be presented relative to a reference alternative and complement results from other decision-support used in planning. Paper 4 found a variety of approaches to quantify impacts of the maintenance stage in LCA. The analysis period was often determined based on the infrastructure’s service life. The maintenance frequency was commonly estimated based on the current practice of maintenance in a region or on performance prediction modelling. Only two of the reviewed papers included the effects of climate change on results of the LCA. How the approaches can be implemented in decision-making depends on their abilities to be standardised for use in procurement and to incorporate multiple scenarios.

Stakeholders involved in transport system policy and planning can use these results as support in considering life cycle impacts in their decision-making practice to reduce environmental impacts in line with national and international targets.