Sustainable Aviation Fuel Deployment Strategies in Europe: Supply Chain Implications and Climate Benefits.

Sustainable aviation fuel (SAF) could reduce aviation's CO2 and contrail climate forcing. This study quantifies the contrail mitigation potential and fuel supply chain costs of a uniform SAF distribution scenario, assuming all departing flights use a 10% SAF blend by mass. Building on this, we propose three SAF allocation strategies that optimize the same SAF supply to maximize contrail mitigation, while considering real-world supply chain constraints and additional costs. A seasonal strategy - providing SAF to all flights from October to February at higher blend ratios (28%) - achieves the highest benefit-to-cost ratio (1.7-7.2) and lowest abatement cost (€14-61/tCO2e). It raises annual reductions in contrail energy forcing (EFcontrail) from 7-8% (uniform vs no-SAF scenario) to 12-13%, with supply chain costs rising by 0.5% relative to the uniform scenario. Two diurnal strategies - one targeting flights after 16:00 local time and another adding a constraint of selecting flights with >250 km of persistent contrails - have lower benefit-to-cost ratios (0.2-2.4) and higher abatement costs (€42-675/tCO2e). Their 1-2% rise in supply chain costs relative to the uniform scenario outweighs the additional contrail climate benefits, as annual EFcontrail reductions only rise from 7-8% (uniform scenario) to 9-17%.