An evaluation of sustainable designs for trucks : A life cycle analysis

Abstract: The largest carbon footprint in the life cycle of a truck comes from the use phase. However, with new fuels and larger renewable energy share in the electricity mix, both the manufacture and the disposal phase show increasing weight in carbon emission. A truck consists in large part of steel, which in production generates carbon dioxide. Hydrogen Breakthrough Ironmaking Technology (HYBRIT), a joint project between SSAB, LKAB and Vattenfall is aimed at changing the Swedish steel production to become carbon neutral by switching from coke as the reducing agent to hydrogen in a direct reduction process. The aim of this project is to evaluate the environmental burden posed by a Scania truck. The thesis is on the metallic pathways in the manufacturing process, as well as different design technologies to determine the environmental impact in general and the specific carbon dioxide footprint for a truck. The main research question to be investigated is: How does the metallic pathways affect the environmental impact of a Scania truck? The objectives of this study are to determine: • how manufacturing with traditional steel affects the environmental impact and carbon footprint. • how manufacturing with carbon neutral steel (HYBRIT) affects the environmental impact and carbon footprint. • how the choice of drivetrain impacts on the sustainability aspects of the truck. The study encompasses a literature review and life cycle assessment (LCA) where four different truck manufacturing scenarios were modeled: the current situation, HYBRIT in Sweden with the energy carrier of today, HYBRIT in Sweden with renewable energy carriers and HYBRIT technology worldwide. Both cases with and without recycling are also studied. As results, the environmental impact from using traditional iron & steel making amounts to 15.6 ton CO2-eq per truck without recycling and 5.8 ton CO2-eq per truck with recycling. Implementing the HYBRIT technology in the Swedish pathway would reduce these numbers to 12.4 ± 0.4 ton CO2-eq and 2.7 ± 0.4 ton CO2-eq respectively. The use phase emissions are expected to continue to dominate the life cycle emissions and lightweight designs, although energy intensive in the manufacturing process, could have a positive contribution in reducing CO2 emission. The HYBRIT process could be a promising technology to mitigate some of the environmental burdens posed by trucks especially in combination with electrification of the drivetrain and an electric grid with a high renewable energy mix.