The European Union's mandatory blending system for sustainable aviation fuel (SAF) exceeded its target in the first year of implementation, helping expand the market. But reliance on imported feedstocks such as used cooking oil remains high, and delays in investment in next-generation synthetic aviation fuel, or e-SAF, have emerged as a task for securing medium- to long-term supply chains.

On Sept. 18, local time, electric-vehicle outlet CleanTechnica reported that the European Union Aviation Safety Agency (EASA) put SAF supplied to EU airports at about 1.1 million tonnes in its 2025 RefuelEU annual aviation technical report. That equalled 2.8 percent of total aviation fuel supplies, exceeding the first-year mandatory target of 2 percent.

The share of SAF rose sharply from 0.6 percent in 2024. It is seen as meaningful because mandatory blending driven by regulation led to an expansion in actual SAF demand and supply.

But feedstocks were concentrated in specific items. Most SAF supplied in the EU is produced via the HEFA method using used cooking oil and animal fats. Used cooking oil accounted for about 80 percent of total SAF supply, category 3 animal fats 11 percent and palm oil mill effluent, or POME-based fuel, about 6 percent.

Dependence on imported feedstocks was also high. While 84 percent of SAF was refined within the EU, 85 percent of the feedstocks used in production were brought in from overseas. That was higher than 69 percent a year earlier. China was cited as a key supplier country of imported feedstocks.

The industry points to the risk that this structure could undermine long-term stability of SAF supplies. Camille Mutrel (카미유 뮈트렐), an aviation policy manager, pointed out that Europe relies heavily on imported feedstocks affected by limited supply volumes and tightening sustainability verification, and that the current structure is not sufficient as a long-term strategy for decarbonising European aviation.

A lack of investment in e-SAF was cited as the biggest challenge. According to EASA, about 60 e-SAF projects are in development in Europe, but none has reached a final investment decision, or FID.

E-SAF is synthetic fuel made by combining hydrogen and carbon using electricity produced from renewable energy sources. EASA judged that if the EU is to gradually raise the share of e-SAF use, projects announced so far need to move into building production facilities and investment phases.

The market has voiced the view that reducing investment uncertainty is more important than easing regulation. The industry argues that to address the lack of e-SAF investment, it should put in place mechanisms to predict the profitability of early projects rather than weakening existing rules or lowering targets.

A two-way auction pilot project being pursued by Germany is also cited in that context. It could support financing for early commercial e-SAF projects by having the government partly reduce price risk between producers and buyers. The European Commission is also reviewing the introduction of an EU-wide two-way auction for sustainable fuels and synthetic fuels.

Diversifying feedstocks is also a key task. Moving away from the current structure concentrated on imported waste-based feedstocks such as used cooking oil could reduce both supply instability and sustainability controversies. That aligns with a proposal by the European Commission to gradually reduce support under the EU Emissions Trading System, or EU ETS, for used cooking oil-based SAF from 2030.

Ultimately, the EASA report shows that the SAF mandate helped expand the market in the short term but faces new challenges in the long term, including feedstock supply chains and e-SAF investment. To sustain its decarbonisation goals for the aviation sector, the EU is expected to need work to change production methods and feedstock structures alongside expanding current SAF supply volumes.