Environmental assessment of hybrid-electric propulsion in conceptual aircraft design

The aeronautic industry is facing increasing pressure to design more efficient and sustainable aircraft to mitigate their impact on the environment. These solutions are mainly focused on: aerodynamics, structures/materials, propulsion and operations. This paper focuses on the potential of electric propulsion systems in different aircraft segments for reducing the environmental impact in the aircraft life cycle. With a twofold contribution and linking different areas, this study presents a methodological proposal for the environmental assessment of the propulsion system change in a consequential Life Cycle Assessment perspective. This methodology uses data from both a modified conceptual aircraft design adapted to hybrid-electric aircraft and a battery study. Results show not only the environmental impacts of the required battery systems for each aircraft segment in a life cycle perspective, but also in what contexts the hybrid-electric propulsion may be considered a best alternative environmentally when compared with fuel propulsion systems. For that, a sensitivity analysis illustrate the results for different electricity mix contexts and for different battery cell capacities. The main contribution for the overall life cycle impact is the process of charging a battery system, therefore the source of electricity generation is crucial for the environmental sustainability of a hybrid-electric aircraft.