Climate change is one of today’s greatest risks. In capital-intensive systems such as transport, investment and infrastructure choices made today lock in emissions and costs for decades. Against this background, the costs of delayed mitigation grow with every year of high emissions. The objective of this dissertation is to develop and demonstrate a transparent, ownership-centered, life cycle based methodology that evaluates decarbonization strategies in terms of both greenhouse gas emissions and costs. For strategy evaluation, emissions from manufacturing, energy supply, vehicle use, and end of life are attributed to the transport system itself. This allocation is appropriate for comparing strategies within transport even though it differs from sectoral inventory conventions used by the Intergovernmental Panel on Climate Change. Climate economics offer levelized cost concepts to express the cost per unit of avoided emissions, and engineering practice provides established approaches for life cycle assessments and total cost of ownership analysis. However, transport studies show recurring issues. These are partially defined or inconsistent system boundaries, isolated scopes that emphasize individual vehicles and thereby neglect system interdependence, weak linkage between environmental assessment and ownership-centered cost analysis (with both often applied in isolation), inconsistent result reporting, and an unsystematic treatment of uncertainty and parameter interdependence that limits credibility and transferability. These gaps motivate a harmonized, transparent, and scenario-based methodology that explicitly addresses system boundaries, integrates environmental and cost assessments through shared data and joint analysis, and uses structured uncertainty and sensitivity analysis.\\ The dissertation addresses two distinct research focuses: the development and application of a structured and harmonized methodology to assess decarbonization strategies in transportation. This includes integrating life cycle assessment and total cost of ownership analysis into one coherent methodology suitable for deriving the levelized cost of carbon abatement. It also establishes shared system boundaries that encompass vehicles, infrastructure, and energy supply so that decarbonization scenarios are directly comparable. In addition, it develops scenario logic that supports consistent comparisons, including multiple functional units and reference flows for results communication. Finally, it presents a joint environmental and economic interpretation through an explicit parameter classification and a reporting scheme that highlights dominance, contributions, significant parameters, and (optional) net-zero decarbonization. The methodology is developed in a stepwise manner within four publications that progressively broaden its scope and further harmonize the overall approach. Publication I establishes life cycle processes for battery-electric and fuel cell-electric vehicles with special attention to batteries, fuel cells, and hydrogen tanks. It relates results to multiple units and emphasizes occupancy and payload interdependence. Core finding: battery-electric vehicles exhibit higher production and end of life emissions but lower life cycle emissions overall across cars, buses, and trucks. Production hotspots are material- and energy-intensive components, while use phase performance is driven by vehicle efficiency and energy carrier carbon intensity. Publication II couples transport simulation with life cycle assessment for urban motorized individual transport. It shows that drivetrain transition to battery-electric alone is insufficient for substantial reductions without improvements in system conditions such as the energy mix, vehicle lifetimes, and fleet composition. The publication introduces the scenario logic that later enables alignment between environmental and cost models. Publication III expands the scope to long-haul heavy-duty road freight in Germany and adds total cost of ownership analysis. Strategies include battery-electric trucks supplied by high-power charging or by electric road systems, fuel cell-electric vehicles with centralized hydrogen supply or on-site hydrogen production, and a diesel reference, all developed within a common scope. Publication IV consolidates these insights into a harmonized methodology to assess decarbonization strategies and calculate the levelized cost of carbon abatement. Additionally, it introduces three extensions: the emission saving potential indicator, a cost–emission delta diagram, and an explicit parameter classification that distinguishes static and dynamic behavior, as well as interdependence of parameters to support consistent uncertainty treatment. The new indicators clarify edge cases: negative cost per ton does not automatically imply large absolute savings, and higher-cost strategies can be warranted when they unlock substantial reductions. Environmentally, the use phase of trucks dominates scenario emissions. Production and end of life emissions from batteries, fuel cells, and hydrogen tanks are significant but outweighed over the complete lifetimes. Economically, operating expenses are the largest contributor to truck ownership cost, driven by energy prices. When strategies are compared jointly on emissions and levelized cost of carbon abatement, battery-electric scenarios achieve the lowest greenhouse gas emissions and the most favorable levelized cost of carbon abatement. Fuel cell-electric scenarios are costlier and, in one configuration, exceed the emissions of the diesel reference scenario. The interpretation identifies lifetime mileage, payload, energy carrier greenhouse gas intensity, and operational expenditures as the strongest influences. Infrastructure costs and emissions are comparatively small relative to energy and vehicle use. Results are specific to the modeled German road transport contexts and may differ where energy mixes, utilization, or infrastructure conditions diverge. Uncertainty is addressed via structured sensitivity analyses rather than full probabilistic propagation, and environmental results focus on greenhouse gas emissions, while broader impact categories are left to future work. The transferable methodology for transparent, scenario-coherent comparisons includes common data handling for life cycle assessment and total cost of ownership, shared system boundaries for vehicles, infrastructure, and energy supply chains, allocation of full life cycle emissions to the transport system for strategy evaluation, and integrated results that report both cost per unit of avoided emissions and emission saving potential with a joint environmental-economic interpretation. The approach is readily applicable to other segments of road transport, such as bus fleets, and adaptable to other regions and policy environments. Future research should establish a closer integration between the methodology and transport simulation models that dynamically represent ramp-up scenarios, infrastructure transitions, and network effects. Furthermore, it should incorporate cost–benefit analyses to support system-level decision-making and extend the analytical scope to encompass additional environmental and social dimensions.
Anne Magdalene Syré (Thu,) studied this question.