A lifecycle assessment of waste-based sustainable aviation fuels blends for advancing the circular aviation economy

The aviation sector is increasingly compelled to mitigate its environmental impact, necessitating the adoption of Sustainable Aviation Fuels (SAFs). This study presents a comprehensive Well-to-Wake (WTW) Life Cycle Assessment (LCA) of waste-derived SAFs blended at a 50:50 ratio with conventional jet fuel (CJF), evaluating seven conversion pathways: Anaerobic Digestion (AD), bio-oil pyrolysis, Gasification with Fischer-Tropsch (GFT), Hydrothermal Liquefaction (HTL), Hydroprocessed Renewable Jet (HRJ) fuel, biogas pyrolysis, and syngas fermentation. The analysis used OpenLCA to evaluate ten environmental impact categories, providing a robust comparative assessment of these pathways. Unlike conventional LCA studies that rely on deterministic point estimates, this research integrates Monte Carlo uncertainty analysis to quantify the variability in environmental performance, offering a probabilistic evaluation of SAF technologies. The findings indicate that bio-oil pyrolysis exhibits the most favorable environmental profile with the lowest impact across multiple categories, including an Acidification Potential (AP) of 0.00141 kg SO₂ eq/kg-km, a Global Warming Potential (GWP) of 0.0803 kg CO₂ eq/kg-km, and an Abiotic Depletion Potential (ADP) of 4.98 × 10⁻⁸ kg Sb eq/kg-km. GFT outperforms both pyrolysis and HTL, particularly in mitigating GWP with a reduction capability of 94.21 % compared to CJF, and demonstrates a resource depletion of 7.09 × 10⁻⁷ kg Sb eq/kg-km. In contrast, specific pathways, such as HRJ and fermentation, exhibit elevated impacts in categories including Human Toxicity and Photochemical Oxidation. HRJ specifically has the highest impact of 9.1 kg 1,4-DB eq/kg-km in Human Toxicity and 8.65 × 10⁻³ kg 1,4-DB eq/kg-km in Photochemical Oxidation, highlighting the necessity for further optimization. Monte Carlo simulations further reveal notable variability across pathways, emphasizing the critical role of uncertainty quantification in SAF technology selection. These insights provide a rigorous foundation for industry decision-making, reinforcing the viability of waste-based SAFs as a key strategy for aviation sector decarbonization while accounting for the inherent uncertainties in environmental impact assessments.