Decarbonizing Aviation Ground Operations 2025

Operational details are harmonized, and all of these have been kept fixed across all technology scenarios. It is assumed that buses travel at an average speed of 20 km per hour within airport grounds, ensuring realistic energy consumption and maintenance estimates. Buses operate 18 hours a day, but carry passengers only for 25% of the operating hours (utilization rate 25%), every day of the year, with an estimated bus range of 90 km/ day. Staffing is standardized, with three drivers per bus per day, each earning a fixed annual salary of €36,580. A 15-year project lifetime is assumed, and financial calculations are thus discounted at a weighted average cost of capital (WACC) rate of 4.56%, aligning with industry norms for infrastructure investments. In this reference case study, airport bus operations continue to rely on a conventional diesel-powered fleet. This approach requires the least infrastructure investment, as it leverages existing fuelling and maintenance facilities. The capex is primarily allocated to the procurement of diesel buses, while the opex is dominated by fuel costs, driver salaries, warranty and insurance, and maintenance. Market average retail price of diesel is assumed at €1.67 per litre and the unit price per bus is €259,000, with no government subsidies considered. Taking into account the various technology options, the following scenarios have been developed based on the key criteria that influence decision-making in airport master planning. Retrofitted electric fleet In this scenario, the airport opts to retrofit existing diesel buses with electric drivetrains, offering a transitional pathway towards electrification. The retrofit cost is assumed at 50% of a new electric bus, with maintenance costs 10% higher than those of new electric buses (€0.407 per kilometre). The operational and infrastructure requirements mirror those of the new electric fleet, including charging infrastructure and driver training. Electric fleet This scenario explores the transition to a fully electric bus fleet, requiring significant investment in both vehicles and charging infrastructure. The capital expenditure includes the purchase of electric buses (average price €550,000) and the installation of charging stations, with additional costs for civil engineering, grid updates, electrical installation and design. Operational expenditure covers battery replacement, charging costs, driver salaries, warranty and insurance, maintenance and driver training. Based on market research, each bus is assumed to have a 386 kilowatt-hour (kWh) battery, providing a usable range of 235 km and a daily charging load of 103.45 kWh. Charging is conducted overnight, with a 3.82-hour average charging time and 95% charger efficiency. Maintenance costs are typically lower than diesel when excluding battery replacement. In this analysis, this battery replacement is assumed to happen in year nine. To reflect potential grant schemes and incentives aimed at supporting low-emission bus deployment, 50% of the capital investment is assumed to be subsidized by the government. This scenario significantly reduces emissions and aligns with long- term sustainability goals, though it requires higher upfront investment and operational adjustments. Hydrogen bus fleet – off-site hydrogen production This scenario considers the deployment of hydrogen-powered buses, with hydrogen supplied from off-site production facilities. The bus fleet operates approximately 4,500 km per day, consuming 428 kilograms (kg) of hydrogen daily, taking average hydrogen bus fuel economy in mind. Each bus is equipped with a 30-80 kg hydrogen tank, offering a range of 200-600 km per refuelling, with refuelling times between 10 and 20 minutes. Based on market research, the average capital cost per bus is €600,000, with a 3.5% annual learning curve and 50% government subsidy on bus capex. All investments are made upfront, and a dedicated refuelling station is installed at the airport. In line with aviation decarbonization ambitions, the baseline assumption for this scenario is the use of green hydrogen, priced at €2.87/kg. The TCO model can, however, also reflect alternative hydrogen price assumptions (e.g. grey or blue hydrogen), allowing adaptation to different regional contexts and production pathways. This scenario enables rapid refuelling and extended range, supporting operational flexibility.Scenario 1 Scenario 2Scenario 3 Decarbonizing Aviation Ground Operations: Alternative Bus Technologies 15