From Potential Routes to Climate Impact: Assessing the Fleet Transition to Hydrogen-Powered Aircraft

The paper presents a methodology aiming to assess the impact of operations of a short- and medium-range fleet transitioning from jet fuel to hydrogen propulsion, considering the constraint arising from the distribution of hydrogen refueling infrastructures across airports, leveraging on the different performance of the two sub-fleets to obtain the least climate-impacting transition. Hydrogen tankering will enable flights to airports that have no hydrogen refueling capabilities, as long as the destination is within half of the operational range of the selected aircraft, at the cost of a slight increase in fuel burn. The proposed methodology aims to assess said increase, while minimizing the expenditure for hydrogen, and the coverage of a reference network, achievable when considering aircraft performance and assumptions on the availability and cost of hydrogen at various airports. The results of such analysis can be used to determine whether a reduction in the design range of a given aircraft is acceptable. Such a reduction would mitigate the impact that the hydrogen tank has on the sizing of the aircraft and its performance. Depending on the considered scenario, a network potential coverage spanning from 81% to 96% can be achieved. Starting from this result, it is possible to assess the transition of a short-haul airliner fleet from jet fuel to hydrogen propulsion, considering the constraint arising from the distribution of hydrogen refueling infrastructures across airports and the different performances (energetic, environmental and economic) of the two sub-fleets. The aircraft assignment to each route is performed with the objective of minimizing either the energy, the carbon intensity or the fuel cost of the overall network, obtaining different route assignment distributions. The results show that the aviation-induced temperature change can be reduced by up to 57% compared to an all-jet-fuel fleet.