An expert-based evaluation of fuel alternatives for green road passenger transport in Germany

To achieve climate-neutrality in Germany by 2045, a profound transformation across all sectors is necessary. The transport sector is responsible for a significant proportion of greenhouse gas (GHG) emissions in Germany and the European Union more widely. With low reductions in GHG emissions, the fossil fuel-dependent German road passenger sector is regarded as one of the primary challenges to achieving the climate-neutrality target. Thus, replacing current fossil fuels with sustainable alternatives is of high importance for defossilizing the road passenger transport sector and moving towards climate-neutrality. However, the identification of promising fuel alternatives and their prioritization for implementation is a complex and multi-dimensional decision-making problem that requires robust tools to generate reliable solutions. For this purpose, a holistic approach was developed using an entropy-based consolidated multi-criteria decision analysis (MCDA) for fuel evaluation under technical and sustainability frameworks based on stakeholder opinions. Methodological and managerial sensitivity analyses are conducted to show the robustness of the results under different circumstances. The results indicate that GHG emissions with an importance of 22%, policy compliance with an importance of 13%, and ecotoxicity with an importance of 9% are the most important criteria for fuel evaluation. On the other hand, electric vehicles and green hydrogen demonstrate the most promising performance for shaping the future road transport sector, followed by advanced biofuels and Power-to-X fuels.