The SAF Value Chain as Compliance Infrastructure: Design and Results for Italy

Humanity is navigating a systemic, multi-faceted polycrisis that strains social cohesion, economic stability, and planetary boundaries. In the energy domain, this tension is commonly summarized as the Global Energy Trilemma: the simultaneous, and often conflicting, imperatives of security of supply, affordability, and environmental sustainability. Transport sits at the nexus of these objectives, and aviation embodies a demanding convergence of constraints: hard-to-abate emissions, uncompromising safety and quality standards, highly globalized supply chains, and stringent expectations for reliability and performance. The decarbonization of aviation therefore requires solutions that are not only technically sound, but also verifiable across whole life cycles and scalable within existing operational and regulatory frameworks. Over two centuries of industrialization have altered atmospheric composition and Earth’s radiative balance in ways now beyond scientific dispute. The frontier has shifted from causality to implementation: how to operationalize rapid, credible, and just decarbonization under real-world constraints of infrastructure, markets, and institutions. This shift has propelled science-based policy frameworks—from multilateral agreements to regional legislation—and has reframed the role of engineering disciplines. Engineers are no longer confined to optimizing steady plants; they are called to design, assess, and scale transition-enabling systems where technical performance, environmental integrity, and institutional verifiability must co-evolve. The European Union has assembled an integrated architecture that pairs long-term climate-neutrality targets with sectoral instruments, market mechanisms, and dedicated funding. In aviation, the logic is deliberately two-sided. On the demand side, binding minimum shares of lower-carbon aviation fuels and monitoring–reporting–verification (MRV) obligations create predictable market pull and a robust evidence base for compliance. On the supply side, innovation grants, research programs, and risk-mitigation tools aim to compress learning curves and bridge the persistent cost and risk differentials that separate sustainable fuels from fossil kerosene. This architecture is intended to translate verified life-cycle performance into bankable value streams, enabling investment to progress from pilots to deployment and aligning technology choice with measurable environmental outcomes. From a technological perspective, Sustainable Aviation Fuels (SAF) offer the most immediate and system-compatible lever to decarbonize aviation because they are drop-in (or partially drop-in) and therefore compatible with existing aircraft and fuel-supply infrastructure. Yet SAF are not a monolith; they constitute a portfolio. Bio-based pathways include HEFA/HVO derived from waste and residue lipids such as used cooking oil (UCO), Fischer–Tropsch syntheses from lignocellulosic biomass, and alcohol-to-jet processes. In parallel, synthetic e-fuels produced via power-to-liquids combine green hydrogen with captured carbon, whereas hydrogen itself—combusted in adapted turbines or used in fuel-cell architectures with liquid hydrogen storage—defines a longer-term trajectory with distinctive infrastructure, safety, and certification implications. These pathways are complementary over time: near-term SAF deployment can deliver immediate reductions and operational learning while hydrogen and e-fuels mature and enabling infrastructures develop. Environmental credibility, however, is not guaranteed by technical feasibility alone. For liquid fuels, life-cycle thinking is indispensable. Life Cycle Assessment (LCA) quantifies impacts along the value chain—from feedstock availability and collection, through pre-treatment and conversion, to distribution and use—and exposes hotspots and trade-offs that tailpipe or energy-only metrics cannot capture. In UCO-to-SAF systems, performance is strongly conditioned by: (i)the coverage, integrity, and logistics of UCO collection; (ii)the provision of hydrogen and utilities (source, efficiency, carbon intensity); (iii)co-product handling and allocation rules; (iv)institutional safeguards—traceability, fraud prevention, sustainability criteria—that determine whether theoretical benefits materialize in practice. Without this systems view, perverse outcomes—unsustainable feedstock displacement, excessive import dependence, or claims with weak additionality—are difficult to detect ex ante. Recent European evidence illustrates both progress and constraint. In the first ReFuelEU baseline (reporting year 2024), suppliers declared 32.1 Mt of total aviation fuels, of which 192.7 kt qualified as SAF—approximately 0.60% by mass. Supply remains feedstock-concentrated and import-dependent: roughly 81% of SAF originates from UCO, and a majority of that feedstock is sourced outside the EU, with deliveries highly concentrated among a limited number of suppliers and airports. On the price side, reference values for 2024 indicate a substantial differential—on the order of €2,085 per tonne for “aviation biofuels” at the NWE hub versus €734 per tonne for conventional aviation fuel—underscoring the economic rationale for calibrated support instruments during market formation. Looking ahead to 2030, EU production-capacity assessments span from an Operating case at roughly 1.4 Mt (today’s in-service facilities) to a Realistic case near 3.6 Mt (adding plants under construction) and an Optimistic case around 5.2 Mt of bio-derived SAF, with an additional ~0.7 Mt of synthetic aviation fuels in high-credibility announcements. The synthetic-fuels pipeline, however, shows delays and depends on final investment decisions and enabling infrastructure. These signals place a premium on coherent policy–finance design to avoid bottlenecks in feedstocks, technologies, and logistics. In parallel with sector-specific regulation, broader decarbonization policy and funding logics—devised for energy-intensive and hard-to-abate industries—inform aviation fuel strategies. Scenario-based assessments of industrial transitions converge on three pillars: (i)demand-pull mandates aligned with verifiable performance (ii)supply-push finance that closes CAPEX/OPEX gaps along learning curves and de-risks first-of-a-kind assets (iii)accounting frameworks that consistently translate life-cycle evidence into eligibility, pricing, and compliance. Together, these elements help mobilize investment at pace while preserving environmental integrity and avoiding lock-ins.