en.Wedoany.com Reported - The aviation industry faces dual challenges in decarbonization: insufficient supply of sustainable aviation fuel (SAF) feedstocks and reliance on imports. Currently, only 22 plants are in operation worldwide, far from achieving the scale needed to replace fossil-based kerosene.
Air traffic continues to grow, with global air travel demand expected to more than double by 2050, yet aviation is one of the hardest sectors to decarbonize. The European Union has begun tightening regulations, requiring since last year that 2% of fuel used by aircraft at EU airports be sustainable. Under the ReFuelEU Aviation regulation, this share will gradually increase to 70% by 2050. Sustainable Aviation Fuel (SAF) can be produced from agricultural and forestry waste, algae, animal fats, and used cooking oil, but there is a gap between industrial reality and the required scale. According to the Mission Possible Partnership, an organization tracking industrial decarbonization projects, approximately 300 plants are in preparation for SAF production worldwide, but only 22 are currently in operation.
Neste's biorefinery in the Port of Rotterdam, Netherlands, operated by the Finnish oil company, is one of Europe's largest biorefineries and has been operating in the port for 15 years. The plant produces 1.4 million tons of renewable products annually, of which 500,000 tons are used for sustainable aviation fuel. An expansion plan, delayed by one year, is expected to reach an annual production capacity of 2.7 million tons by 2027, with 1.2 million tons for SAF, which would make it the world's largest biorefinery if realized. Hanna van Luijk, Vice President of Renewable Refining Netherlands and Head of the Biorefinery at Neste, told El Confidencial that the company's advantage lies in its scale and experience, having begun researching renewable fuels in the early 2000s and entering the SAF field in 2011.
The technology used by Neste, called NExBTL, is based on the same principle as renewable diesel HVO. By removing oxygen molecules and restructuring compounds, it produces molecules with properties similar to fossil hydrocarbons, mimicking the kerosene it replaces. The process includes technology to prevent the fuel from solidifying at extreme temperatures as low as -47°C at altitude. This type of fuel can be used in existing aircraft without engine modifications, earning it the label "drop-in" fuel. However, current regulations do not allow aircraft to be fueled solely with SAF; sustainable fuel must be blended with fossil kerosene, typically with a maximum blend of 50%, due to the influence of aromatic compounds in fossil fuels on seal behavior in older engines, an effect that SAF cannot replicate in the same way.
Neste has supplied SAF to airlines such as Air France-KLM, United Airlines, Emirates, Lufthansa, Finnair, and Singapore Airlines, as well as airports in Amsterdam and San Francisco. It also sells sustainable fuel to logistics giants like Amazon, FedEx, and DHL. In Spain, Iberia, Iberia Express, Level, and Vueling purchased 28,000 tons of SAF from Repsol in 2024. Repsol produces sustainable fuels at several plants in Spain, including a facility in Cartagena dedicated to renewable fuel production. Moeve and BP also produce SAF, but output remains limited. According to estimates cited by El Confidencial, Spain would need approximately 30 biorefineries to fully decarbonize air transport, while globally, hundreds or even thousands of such facilities would be required.
Most SAF produced from fats and oils relies on imported used cooking oil, which is transported through global logistics chains from restaurants, hotels, the food industry, households, and even sports venues (from the Asia-Pacific, Europe, and the Americas) to European biorefineries. Marcos Raufast, Head of Projects and Public Policy at Ecodes and an aviation expert, warns that importing raw materials generates emissions. Transporting imported used cooking oil to produce HEFA fuel emits over 24,000 tons of CO2, equivalent to the emissions of approximately 300,000 round-trip passengers between Lisbon and Porto. Neste argues that despite supply chain emissions, the global balance is still better than fossil fuels, and its renewable products have helped customers reduce emissions by 14.2 million tons. According to Ecodes, 85% of feedstocks used for biofuels come from countries such as Indonesia, Malaysia, China, the United States, or Brazil. In Spain, for example, only 16% of the used cooking oil converted into sustainable kerosene is domestic, with about 79% coming from Asia. Raufast believes that even China, one of the world's largest producers of waste oil, cannot produce all the SAF it needs, and replicating a model similar to fossil fuel imports will not bring energy sovereignty.
The industry is seeking alternatives. Neste is researching new feedstocks, including acidic oils from wastewater, lignocellulosic materials, and agricultural and forestry residues. Other technological pathways include converting methanol into aviation fuel or producing synthetic e-SAF, which is obtained from water, renewable electricity, and CO2 captured from the atmosphere. Raufast considers e-SAF a truly scalable technology but notes it still faces challenges in cost, production, and the availability of renewable electricity. The aviation industry needs to reduce emissions during a period of rapid demand growth, and sustainable fuels are an important part of the transition, but not a complete solution. Used cooking oil can help decarbonize some flights, but it is insufficient to support the future of aviation on its own.
