Tobias Kahnert

Sustainability Assessment of Alternatives to Fossil-Fuel Based Commercial Aviation

Fossil-fuel-based aviation is commonly regarded as a major contributor to global warming and accounts for more than 2% of global CO₂ emissions. Industry and academia have been exploring a range of alternatives to fossil-fuel-based aviation. However, the lack of comparability between the design concepts, the trade-offs between performance attributes, and the multiple interacting stakeholders (aircraft manufacturers, airlines, airports, customers, governments) make it hard to determine the feasibility and the sustainability of the alternatives.

This dissertation conducts a sustainability assessment of biofuel, electric and hydrogen-based aircraft alternatives. Drawing from literary insights and industry data, quantitative models are built to assess the performance of the alternatives. The models evaluate the alternatives against the following criteria: capital investment, operating cost, range, global warming potential, socio-environmental impact and long-term environmental criteria.

The criteria are then weighted based on stakeholder scenarios. The overall ranking of the alternatives is established using an Analytical Hierarchy Process (AHP). Building on the results of the AHP together with a sensitivity analysis, the paper identifies the opportunities and challenges in the transition towards more sustainable aviation.

Overall, this research aims to reduce uncertainties around the available alternatives to fossil-fuel-based aviation. In so doing, it aspires to encourage appreciation regarding the complexity of the ongoing transition towards sustainable aviation alternatives.