Government subsidies and incentives are another critical factor shaping TCO. Airports and ground service equipment providers have access to a wide range of support schemes for zero-emission buses and related infrastructure. In North America and Europe, programmes frequently cover 40-100% of the incremental costs for vehicles and charging infrastructure through grants, rebates or tax credits. Notable examples include the Federal Aviation Administration (FAA) Zero Emissions Airport Vehicle Programme (United States), the Zero Emission Transit Fund (Canada) and the EU Alternative Fuels Infrastructure Facility (European Union), all of which provide substantial support tailored to airport projects. Additional opportunities often exist through state, provincial or utility-level programmes. In the Gulf region, while open-call grants are less common, support is provided through government- led pilot projects, procurement mandates and strategic partnerships aligned with national sustainability strategies. Non-monetary incentives such as tax breaks are also frequently offered, further improving the financial case for adoption. A detailed table of available subsidies and incentives across regions is included in the appendix for reference. Each bus technology also has its own unique sensitivities. For example, the cost of fuel is especially important for diesel buses, and this price could vary further when factoring in the potential price premium of HVO. The price of electricity and the initial purchase cost matter most for electric buses. Hydrogen buses are particularly sensitive to how long they are used, because their upfront and infrastructure costs are high. If the fleet is not sized correctly or if there are limits on maintenance and refuelling flexibility, it becomes harder to keep costs down. Other factors, such as the average speed of the buses and the hours that the airport operates, also play a role by affecting how long the buses spend in motion, influencing the maintenance costs and the idle time for refuelling and charging. In Appendix 2, further considerations on the assumptions taken for each of the technologies are analysed. In summary, while energy prices, purchase costs and how long the buses are used are the most influential factors in all scenarios, it is government subsidies and their influence on capex that would directly affect upfront costs and whether these can be offset over the lifetime of the assets. The main exception to this analysis concerns the hydrogen bus scenario. Here, both the maturity of hydrogen bus technology and the local availability of hydrogen fuel can significantly influence capex. Additionally, the cost and reliability of hydrogen supply – linked to hydrogen production infrastructure – can impact opex. For airports considering hydrogen buses, a more detailed assessment of both technology readiness and fuel supply logistics is recommended to ensure efficient fleet operation. These insights highlight the importance of careful planning and local context when choosing and managing alternative bus technologies at airports. Additional reflections The transition to hydrogen-powered ground operations is already challenging, but this takes place while air transport is also exploring this technology, with significant opportunities for collaboration but also complex challenges. While some airports are currently studying infrastructure planning for supporting hydrogen bus fleets – primarily through gaseous hydrogen supply – future demand from hydrogen-powered aircraft will require a fundamental shift in both scale and technology, particularly towards liquid hydrogen (LH2) production, storage and handling. A key observation is the current disconnect between hydrogen infrastructure for ground vehicles and the anticipated needs of aviation. As hydrogen aviation matures, airports will need to bridge this gap, integrating infrastructure that can flexibly support both gaseous and liquid hydrogen, and ensuring that investments made today are ready for tomorrow’s multimodal hydrogen ecosystem. This is because industry and academia suggest that liquid hydrogen may be more suitable for aircraft propulsion in the future, though current ground operations rely predominantly on gaseous hydrogen. This forward-looking scenario was also part of the research for this paper. The main difference between the off-site hydrogen production scenario (number 3 previously described) and the on-site hydrogen production scenario is the infrastructure needed to adopt a hydrogen bus fleet within the boundaries of an airport that has made a complete transformation of its landscape, including capabilities for liquid hydrogen production, storage and delivery. The capex required for on-site hydrogen production and liquefaction is substantial, with estimates exceeding €450 million and annual opex heavily influenced by electricity prices and liquefaction efficiency. Liquefaction remains the primary cost driver, and the TCO is highly sensitive to both the price of green hydrogen and the cost of electricity. Technological advances are expected to reduce both capex and opex by 2050, but the need for a “green premium” over conventional fuels would persist in the near term. Decarbonizing Aviation Ground Operations: Alternative Bus Technologies 23

Decarbonizing Aviation Ground Operations 2025