Abstract
This life cycle assessment study evaluates the environmental performance of aviation fuels produced from two perennial grasses, switchgrass and miscanthus, grown on abandoned European cropland with and without irrigation. The system boundaries include the conversion of biomass to jet fuel via two pathways, Fischer–Tropsch and alcohol-to-jet, each evaluated with and without carbon capture and storage (CCS). The assessment quantifies climate impacts, water use, and biodiversity implications to determine the conditions under which these fuels offer meaningful environmental benefits. Results show that the choice of feedstock, conversion pathway, and water management strategy strongly affects net greenhouse gas emissions. Fischer–Tropsch fuels combined with CCS achieve the lowest climate impacts and can deliver net-negative emissions. Near-term climate outcomes are influenced by short-lived species such as methane, black carbon, and contrail-induced cloud formation, whereas long-term impacts remain dominated by carbon dioxide emissions. Water demand emerges as a critical factor, with irrigation substantially increasing national water footprints, particularly in regions already facing water scarcity. Rainfed cultivation reduces these pressures but remains sensitive to regional water vulnerability. Overall, producing aviation fuels from perennial grasses on marginal land presents a viable pathway for reducing aviation-related emissions if implemented with careful consideration of water availability, biodiversity impacts, and region-specific environmental constraints.