Environmental life cycle assessment and operating cost analysis of a conceptual battery hybrid-electric transport aircraft

Abstract

Noise and greenhouse gas emission targets set by e.g., the EU commission, NASA, and ICAO oblige the aviation industry to reduce its environmental footprint. Battery-powered hybrid-electric aircraft are currently being investigated in this regard as they can potentially reduce in-flight greenhouse gas emissions and noise. However, most studies to date have focused on the CO2 emission reduction potential instead of considering the total life cycle environmental impact. Hence, within this study an environmental life cycle assessment method for a hybrid-electric aircraft is developed and applied, supplemented by a direct operating costs analysis. This allows the simultaneous evaluation of the environmental impact reduction potential and the economic consequences for aircraft operators. This demonstrates the faced trade-off and contributes to a meaningful review process. A single-aisle transport aircraft (A320 class) serves as a use case for the established methodology. It consists of the conceptual aircraft design, the environmental life cycle assessment, and the direct operating costs analysis for a conventional reference aircraft and a hybrid-electric aircraft with a discrete parallel powertrain architecture. It should be noticed that the focus of this study is the comparison of conceptual aircraft designs of the same fidelity on system level, in lieu of the detailed modeling of a hybrid-electric aircraft. Results show that for a degree of hybridization of 0.3, the environmental impact of the hybrid-electric configuration increased by 15.1%, while the operating costs increased by 41.0% compared to a conventional reference aircraft. For a future scenario, favourable for hybrid-electric aircraft with i.a. renewable electricity production, the environmental impact could be reduced by 7.0% compared to the reference aircraft. At the same time, the operating costs gap between both configurations decreases to + 26.8%. Hybrid-electric aircraft should therefore be investigated further as a potential solution to reduce the environmental impact of aviation, if simultaneously to developing them the expansion of renewable energies is fostered. Nevertheless, this reduction in environmental impact involves a high direct operating costs penalty.