Energy Storage System Selection for Optimal Fuel Consumption of Aircraft Hybrid Electric Taxiing Systems

Aircraft taxiing is conventionally performed using the main engines' inefficient idle thrust. Therefore, in line with greener aviation, the electrification of taxiing is the most viable option to reduce emissions, noise, and fossil fuel consumption during ground operations. This article studies the potential of hybridizing the conventional electric taxiing system, which is currently driven by the auxiliary power unit, with an electrical energy storage system, comprising commercial high-energy and high-power lithium-ion batteries, for the purpose of reducing fuel consumption. Hence, a power distribution optimization is formulated to minimize fuel consumption over a typical worst case taxi-out profile. Three different energy management strategies are presented for a narrow-body airplane. The optimization is performed for the selection of off-the-shelf batteries so that their impact on fuel savings can be evaluated in the early design stage. The study showed that a wide range of savings is achievable according to the selected strategy, the added weight allowance, and the battery characteristics. Considering a 180-kg added weight allowance and covering the three investigated strategies, up to 72% of taxiing fuel is saved.