Battery electric buses represent a new era of investment. The vehicles themselves are more expensive than diesel ones, and the need for charging stations – and related significant upgrades to airport electrical systems, including grid upgrades and battery storage systems – can make the initial outlay substantial. Yet, as the market matures and more manufacturers enter the space, costs are gradually coming down and the long-term value proposition is improving. Hydrogen buses, meanwhile, are at the frontier of innovation. Their high purchase price and the need for specialized, often bespoke, fuelling infrastructure make them the most capital-intensive option. For airports considering hydrogen, the decision is as much about future readiness and ecosystem development as it is about immediate cost. Ongoing operating costs Diesel buses, while cheap to buy, can be more expensive to run than other options. Fluctuating fuel prices and the maintenance demands of combustion engines add up over time. Retrofitted buses can offer some relief, with newer components reducing maintenance needs, but they still face the dual costs of diesel and electricity, especially when airports choose to have both system coexist for a while. Battery electric buses, by contrast, shine in terms of ongoing cost efficiency. Electricity is generally less expensive and more stable in price than diesel, and the simplicity of electric drivetrains can mean fewer breakdowns and lower maintenance bills. Over the lifespan of the vehicle, these savings can be significant, helping to offset the higher upfront investment. Hydrogen fuel cell buses also benefit from reduced mechanical complexity, but the cost and availability of hydrogen fuel remain barriers. As the technology matures and the hydrogen supply chain grows, these costs may fall, but for now, they are a key consideration. Airport operations Diesel buses are easy to refuel and maintain, and well-suited to established operational routines. Retrofitted buses fit comfortably into this pattern, requiring only modest adjustments to accommodate charging. Still, the need to remove vehicles from service for conversion and the logistics of refurbishment can create temporary capacity gaps that airports must plan for. Battery electric buses introduce new dynamics. Charging schedules must be carefully managed to ensure vehicles are ready when needed, and route planning may need to adapt to range limitations, especially in airports with demanding duty cycles. However, electric buses are quieter and cleaner, enhancing the passenger and staff experience and reducing the airport’s environmental footprint. Hydrogen buses offer the promise of long range and rapid refuelling, combining the operational flexibility of diesel with the environmental benefits of electric. While the lack of widespread hydrogen infrastructure remains a challenge, the introduction of hydrogen also requires tailored training and safety protocols – comparable to the adjustments already made for other fuels such as electricity, diesel, propane or natural gas. Airports investing in hydrogen are already demonstrating that it can be deployed safely and reliably, with affordability expected to improve as adoption scales. Beyond these day-to-day operational factors, the transition to battery-electric and hydrogen buses introduces a new layer of complexity and uncertainty for airport operators. An industry taskforce led by Airports Council International (ACI) World14 suggests several steps to tackle these, including: A comprehensive aerodrome compatibility study before operations can begin, ensuring that infrastructure, safety and operational procedures are fit for purpose – not only for buses, but also in anticipation of future hydrogen or electric aircraft. Security and fire safety, as both battery and hydrogen vehicles present unique risks. Battery fires can be prolonged and emit toxic fumes, while hydrogen, though clean burning, demands specialized detection and response protocols. Airports must also plan for significantly increased electrical power demand, as stands will need to support simultaneous charging of buses and, eventually, aircraft – potentially necessitating major upgrades to energy infrastructure. The introduction of new fuel types may require segregated parking stands, which could reduce stand capacity and complicate ground support equipment logistics. Furthermore, operational procedures such as verifying electrical connections before energizing cables, and reassessing stand design and risk management, become critical to ensure safety and resilience. Ultimately, while each technology presents a distinct balance of environmental benefits, operational considerations and investment requirements, the decision for any airport will depend on how these factors translate into long-term value. To provide a clearer basis for comparison and support evidence- based decision-making, the next section delves into the total cost of ownership (TCO) analysis – outlining the methodology, key assumptions and resulting insights that underpin a comprehensive evaluation of each pathway’s financial and operational implications over the full life cycle of the fleet. Decarbonizing Aviation Ground Operations: Alternative Bus Technologies 13

Decarbonizing Aviation Ground Operations 2025