Towards sustainable regional aviation: Environmental potential of hybrid-electric aircraft and alternative fuels

The aviation sector needs to reduce its environmental impacts, like climate change and air pollution. New hybridelectric aircraft concepts may contribute to abating part of these impacts. But to what extent and under which conditions? This study addresses these questions in the context of regional aviation and identifies technologies and concrete actions required for more environmentally sustainable aviation. The environmental impacts of emerging hybrid-electric aircraft configurations deployed in 2030, 2040, and 2050 have been comprehensively quantified using prospective life cycle assessment. The entire life cycle of the conventional and hybrid-electric aircraft configurations was encompassed, covering various technologies and systems like batteries, fuel cells, hydrogen, and selected alternative aviation fuel (AAF) systems. For these elements, detailed life cycle inventories stemming from primary data, literature, and prospective environmental databases were used, and uncertainty was evaluated. Results showed that hybrid-electric aircraft with Li-ion batteries appear as a promising transition technology in the short-term while aircraft propelled by fuel cells using hydrogen from electrolysis yield important environmental benefits relative to conventional aircraft in longer time horizons. In contrast, the studied AAFs present little or no environmental benefits when considering environmental impacts holistically, demonstrating the need to revise existing AAF frameworks and incentives globally. Environmental burdenshifting from flight emissions in conventional aircraft systems to airport operations and aircraft manufacturing in hybrid-electric aircraft is also observed in the results, thus calling for strengthened support to airports in their sustainability management and increased integration of ecodesign practices in future aircraft design and development.