As industry and airport, we have defined concrete ambitions and commitment to shape a future that is not only more sustainable, but also one that is characterized by healthier environments for everyone working at Schiphol and our neighbors around. Sustainable Taxiing here fore is an important enabler since it allows us to move aircrafts to and from the runway while keeping their engines off. We do so with a special tow vehicle that incorporates the conventional towing mode as well as a unique ‘pilot control mode’ allowing the pilot to steer the aircraft while being attached to the towing vehicle.
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In 2022, we procured two of those vehicles to validate the newly developed Concept of Operations with our consortium partners in a live operational context. Those vehicles are two of only very few in the world. Today, they are still powered by a hybrid combination of electric and diesel engines and consume 95% less fuel when taxiing than aircraft engines would normally use. However, the next generation will be zero-emission vehicles to move the needle on Sustainability further.
Schiphol expects to achieve a total savings of 50-85% on fuel consumption during taxiing because engines need to warm-up for a few minutes before departure. Measurements will be taken during the validation phase to see what fuel savings can be made in practice.
Keeping engines off while taxiing translates in significant fuel savings. By reducing fuel usage, sustainable taxiing also cuts down on harmful emissions, including CO2, nitrogen oxides, and ultra-fine particles. This contributes to a healthier environment and helps Schiphol meet our sustainability commitments. Despite improving Schiphol's environmental footprint, introducing a new concept of operations that enables engines off taxiing can streamline ground operations, reduce congestion and mitigate delays on taxiways.
The impact of sustainable taxiing on total fuel consumption and emissions varies significantly based on flight duration. For longer flights, taxiing might account for around 4% of total fuel use, while for shorter flights, it could be about 9%. These percentages are rough estimates and can fluctuate based on various assumptions, making them more indicative rather than precise measures.
We can also calculate the percentage of fuel we want to save, relative to the total fuel consumed whilst taxiing. This is the most common way to calculate savings. This method also leaves us with a pretty big difference between the lower and upper percentages, ranging from conservative savings of 50% to an optimistic 85% gain. While testing the solution we could validate savings of fuel and hence all corresponding emissions of about 75%.
Finally, we can compare one minute of sustainable taxiing with one conventional taxiing minute. Ideally, given engines are kept off while taxiing, we would reach a 100% saving. However, given the APU must remain running during the taxiing operation, we can’t realize the full potential of fuel savings but get close to the ideal.
With Sustainable Taxiing, we do not only save CO2 emissions, but additionally drastically reduce the exposure of all people working on the apron to UFP. UFP are Ultra Fine Particles that are produced by burning fuel and Schiphol together with the sector is taking concrete steps to create healthier working conditions where those potentially harmful emissions are drastically reduced.
Sustainable Taxiing needs close collaboration between airlines, ground handlers, airtraffic control and Schiphol airport. Therefore, collaboration is organized in a consortium of various sector partners working jointly towards defined ambitions. As consortium we are validating Sustainable Taxiing and the corresponding Concept of Operations (CONOPS) through live operational trials, simulations and feasibility studies. The validation efforts over the last years have shown promising results, which is why we are looking with confidence to the future and are gearing up to grow impact with the next steps. You will be reading more about them here soon!