Evaluation of system-level implications of introducing hydrogen-powered aircraft on the passenger air transportation network

The global aviation industry faces a pronounced challenge to mitigate its contribution to anthropogenic climate change. While total carbon emissions contribution of passenger air travel was estimated to account for around 3% of the global carbon emissions in 2019, this is projected to increase due to the hard-to-abate character of emissions from jet fuel powered aircraft. One potential pathway that is recently gaining attention in research, policy, and industry is the transition towards using green hydrogen as zero-carbon fuel. Next to technological, infrastructural, and economical challenges, this would introduce a wide range of impactful changes to a system centred around safety and reliability. This thesis employs a holistic approach and examines these changes from a flight network perspective, focusing on passenger transport in Europe. It uses a two-step approach: first, top-level aircraft requirements (TLAR) for a hydrogen aircraft are determined to maximise the emissions reduction in a fixed network. Then, the changes the chosen aircraft configuration would impose on the air transportation network in Europe are identified. For this purpose, it utilises network modelling and linear optimisation techniques. The thesis recreates the air transportation network using demand and direct operating cost optimisation, without considering revenue and airline-specific factors. It illustrates that an aircraft with 140-seats and 2,000 km range could be able to address more than half of carbon emissions caused by intra-European passenger flights by 2050. The introduction of hydrogen aircraft will have substantial impact on network structure, including flight frequency, capacity, and stopover routes, depending on seat capacity and range of the hydrogen aircraft design. Lastly, it shows that air-ports that have a favourable green hydrogen supply could benefit from the introduction of hydrogen aviation.