Green hydrogen and CO2 capture for synthetic aviation fuels: a review of power-to-liquid pathways, sustainability metrics, and commercial scale-up challenges

This review provides a structured, pathway-level assessment of Power-to-Liquid (PtL) e-fuel production for aviation, covering hydrogen electrolysis (AWE, PEM, SOEC, AEM), CO 2 -to-syngas conversion (reverse water–gas shift vs. co-electrolysis), fuel synthesis routes (Fischer–Tropsch, methanol-to-jet, DME-to-jet, ethanol-to-jet), and CO 2 sourcing strategies (point-source, biogenic, direct air capture), benchmarked against their technology readiness and EU RFNBO regulatory eligibility. A synthesis of life-cycle assessment literature shows that the well-to-wake carbon intensity of PtL jet fuel spans an unusually wide range, from below 8 gCO 2 e/MJ to over 100 gCO 2 e/MJ, occasionally exceeding the fossil Jet A-1 baseline, driven primarily by the carbon intensity of the electricity source rather than the CO 2 origin. Across the studies compared, the mean reported value (21.3 gCO 2 e/MJ) still satisfies the > 70% reduction threshold required under the ReFuelEU Aviation Regulation. Current PtL production costs (2.2–5.5 USD/L, up to ∼ 8 times higher than fossil Jet A-1) are projected to fall to 0.71–0.81 USD/L by 2050, driven mainly by declining electrolyzer and renewable electricity costs. A pathway-level comparison combining electrolyzer type, CO 2 source, and synthesis route reveals substantial, unevenly distributed gaps in reported techno-economic data across the PtL value chain. The review further identifies the 2036 regulatory cut-off for fossil point-source CO 2 eligibility and the geographic mismatch between renewable electricity and CO 2 feedstock availability as underexplored constraints on long-term PtL competitiveness, while noting that commercial deployment remains limited (four operating plants as of 2025) despite a project pipeline expected to exceed 250,000 t/year of capacity in the coming years.