One of the most important ways to make air travel more climate-friendly is through Sustainable Aviation Fuels (SAF). However, this is a broad and general term that encompasses a wide variety of fuel types produced in different ways. How environmentally friendly are the various types of SAF really? And which of these are suitable for production in the Global South, thereby contributing to both climate protection and economic development there? We explore these questions here.

The most widely used type of SAF at present is fuel produced from fats that have been treated with hydrogen (Hydroprocessed Esters and Fatty Acids, HEFA). According to the EASA dashboard, HEFA accounted for almost the entire volume of the 1.1 million tons of carbon-neutral fuels fuelled at airports in the European Union in 2025. The HEFA process is relatively inexpensive and technically mature. In the EU, HEFA complies with the provisions of the ReFuelEU Aviation Regulation. In Europe, it is primarily produced from used cooking oil and animal fats that have no other use. However, the available supply of such waste fats is very limited. Producing larger quantities of HEFA for aviation would therefore require oils from energy crops. These crops would have to be grown specifically for this purpose, requiring a great deal of land, of which there is little available in the EU.

Energy crops such as oil palms and soya are grown mainly in developing countries, where they compete with food crops, thereby jeopardising the food security of the local population. The cultivation of e.g. oil palms and soya beans also often leads to the destruction of rainforests with high levels of biodiversity. Similar problems arise with alcohol-based fuels, which are mainly produced from sugar cane. According to the SAF Outlook published by CENA Hessen, their share of global SAF production is set to rise to over 10 per cent by 2030.

Synthetic Fuels Are a Long Time Coming

A more environmentally friendly type of SAF is e-kerosene, which derives its energy from electricity generated from renewable sources. There are several technical approaches. In one process (RWGS and Fischer-Tropsch), green hydrogen is produced from water by electrolysis and is subsequently combined with CO₂ to produce synthesis gas via the reverse water-gas shift reaction (RWGS). The Fischer-Tropsch process then converts the synthesis gas into a synthetic crude, which can subsequently be refined into jet fuel range kerosene at a refinery. The “food vs. fuel dilemma” no longer applies directly, although e-kerosene still requires CO₂ as a raw material. If the CO₂ comes from fossil-based industrial sources, such as flue gases from steelworks, cement works or refineries, the carbon footprint of the kerosene produced in this way is still significantly better than that of fossil-based kerosene. However, it is still tied to an industry of climate-harming fossil emissions. For this reason, the EU stipulates that CO₂ from fossil-fuel-based industrial emissions may only be used as a raw material for e-kerosene until 2041. After that, only CO₂ from biogenic or from direct air capture will be eligible, and biogenic CO2 must meet the sustainability criteria for the EU Renewable Energy Directive. From an environmental perspective, these CO₂ sources are far less problematic than the biomass used for HEFA, because they only need to supply the carbon, while the energy comes from renewable electricity (via the hydrogen).

The potential of green electricity, if there were a massive expansion worldwide, would theoretically and in the long term be sufficient to supply the entire global aviation sector with e-kerosene. However, the local population and industry should always be supplied with electricity first and as a priority, per the atmosfair fairfuel standard. There are also resource and distribution issues to be resolved with e-kerosene, albeit significantly simpler ones than with HEFA.

The CENA report indicates that, to date, no final investment decision has been made for any of the larger e-kerosene projects in Europe. Consequently, the forecast share of 15 per cent e-kerosene in total SAF production by 2030 appears highly uncertain. This is due, among other things, to technological problems and the associated hurdles for investors and banks (see the editorial in the October 2026 atmosfair-newsletter).

Two further environmentally friendly routes to SAF are still at an early stage of development: biomass-to-liquid (BtL) and the methanol-to-jet route (MtJ), an alternative route to e-kerosene that uses methanol as an intermediate. Both are considered promising options for production in developing countries. For BtL, agricultural and forestry residues are often available as a low-cost feedstock, although they are not always unused, and collection and logistics carry complexity. E-methanol is technologically simpler to produce than Fischer-Tropsch-based fuels, and many developing countries have sufficient resources for low-cost renewable electricity. SAF production could therefore create jobs and sources of income, particularly in biomass supply chains and renewable energy, while technology transfer can open up new opportunities for industrial development.

Air travel could be made more environmentally compatible, if airlines used kerosene produced with electricity generated from renewable energy sources (Photo: Getty Images, Scharfsinn86).

Biomass-to-Liquid: Kerosene from Crop Residues

A BtL plant gasifies solid waste biomass and then converts the resulting synthesis gas into crude kerosene using the Fischer-Tropsch process. In developing countries, there are large quantities of wood chips, cereal straw, rice husks and other residues that have so far either gone unused or been burnt in ways that are harmful to the environment. An atmosfair study calculated that a total potential of 400 million tons of waste biomass is generated each year in developing and emerging economies, that satisfies both environmental sustainability and social criteria.

atmosfair’s sister organization, Solarbelt, demonstrated that solid bio-waste can indeed be converted into aviation fuel during production campaigns with BEST in Vienna, where both cashew shells and coconut shells were successfully converted into Fischer-Tropsch synthetic crude, suitable for upgrading to SAF. This makes it clear that BtL technology works in principle and is appropriate for regions with large quantities of unused solid waste. There, the production of BtL kerosene can create jobs and provide a valuable export product. However, challenges include the capital-intensive nature of the technology, the technical adaptation of the process to different and non-homogeneous waste streams, and the transport of widely dispersed organic waste to a central BtL plant.

E-Methanol: Fuels and Chemical Feedstocks ‘Made in Africa’

Another key feedstock for sustainable aviation fuels (SAFs) from which developing and emerging economies can benefit is e-methanol, which can be converted into jet fuel via the methanol-to-jet (MtJ) process. Conventionally, methanol is produced from a synthesis gas consisting mainly of carbon monoxide (CO) and hydrogen, similar to the RWGS and Fischer-Tropsch route to e-kerosene described above. Advanced catalysts now allow methanol to be synthesised directly from hydrogen and carbon dioxide (CO₂), eliminating the separate RWGS step. This simplifies the use of biogenic CO₂ and can potentially reduce production costs compared with the Fischer-Tropsch route. In July 2026, the standards organisation ASTM approved methanol as a feedstock for the alcohol-to-jet production pathway, paving the way for a further route to SAF, using either biogenic methanol or e-methanol.

Methanol is also suitable as a feedstock for the domestic chemical industry. Kenya, for example, imports approximately 8,000 to 10,000 tons of methanol each year, at a significant cost premium relative to other regions and counties. Supplied mainly by the USA and Saudi Arabia, significant handling and distribution costs for the smaller import volumes are incurred. In the future, it could meet this demand with methanol produced domestically from green electricity and carbon dioxide. E-methanol can also already be used as a fuel in marine engines today.

For these reasons, Solarbelt is exploring potential sites for e-methanol plants in developing countries that have the potential to operate profitably in the long term. There are a number of opportunities: in some countries, large surpluses of electricity from renewable sources are now available, exceeding local demand. This electricity is then suitable for the production of green hydrogen via electrolysis. Ethiopia, for example, generates more electricity than it requires domestically and has become a net exporter of electricity. Half of this is generated by the Grand Ethiopian Renaissance Dam alone, which was completed last year. There are also non-fossil sources of CO₂ in these countries, such as those arising from sugar production for food. The gas is produced when bagasse is burnt or molasse is fermented to produce ethanol. As long as the CO₂ comes from waste products of sugar production, it can be environmentally and socially sustainable.

Particularly in the case of sustainable aviation fuel based on e-methanol, the advantage is that the first step – the production of e-methanol – is technically straightforward and can already be carried out in developing countries today. As methanol is relatively easy to transport, it can be readily exported to industrialised countries, where it can be processed into kerosene (Methanol-to-Jet, MtJ, see above). However, commercial MtJ plants do not yet exist and are only now being developed in Europe. They are high-tech and capital-intensive, which is why the division between developing and industrialised countries for this type of kerosene production remains sensible until the methanol-to-jet process is technically mature and can be implemented in developing countries. This would enable these countries to generate the full value chain – from raw materials through methanol to kerosene itself – in the long term.

Such SAF produced in Africa can therefore be more cost efficient than comparable fuels from Europe and other continents due to lower feedstock costs, making it competitive on the global SAF market. In this way, pilot plants in the Global South can contribute to the defossilisation of aviation, as well as shipping and the chemical industry.