Sustainable Aviation Fuels Versus Conventional Jet Fuel: Emissions, Climate Effects, and Deployment Challenges A Comparative Review

Abstract

Sustainable aviation fuel (SAF) is being developed as a lower-lifecycle-greenhouse-gas (GHG) alternative to conventional petroleum-derived aviation turbine fuel. Its environmental performance, however, is not uniform: it depends on feedstock origin, conversion pathway, process energy, hydrogen source, transport, land-use effects, and lifecycle-assessment (LCA) assumptions. This structured narrative review compares SAF with conventional Jet A-1 across lifecycle GHG emissions, selected non-CO₂ climate effects, fuel pathways and technical compatibility, production scale, cost, feedstock constraints, and policy. Particular attention is given to the ECLIF3 flight campaign, which measured 35% fewer soot particles and 56% fewer contrail ice particles per unit mass of fuel burned for 100% HEFA-SPK than for the reference Jet A-1 under the tested cruise conditions. A global climate-model simulation in the same study estimated a 26% reduction in contrail radiative forcing for a modelled 2018 fleet scenario; this is a model result, not a direct measurement of global temperature change. IATA estimated SAF production at approximately 1 million tonnes in 2024 and projected 1.9 million tonnes in 2025 and 2.4 million tonnes in 2026, equivalent to approximately 0.6% and 0.8% of jet-fuel consumption in 2025 and 2026, respectively. The review finds that SAF can deliver substantial lifecycle GHG reductions when produced through well-performing pathways, but its deployment is constrained by price premiums, finite sustainable feedstocks, conversion capacity, and inconsistent LCA assumptions. SAF should therefore be evaluated pathway by pathway and deployed alongside aircraft-efficiency improvements, operational measures, and other climate-mitigation strategies.