Sustainable aviation fuels (SAFs), will be crucial to decarbonise aviation in the short term. SAFs are available on the market as a certified drop-in fuel, blended with conventional jet fuel. There are currently 6 pathways for blending bio-based fuels with conventional aviation fuels that are certified by the American Society for Testing and Materials (ASTM) International, with the maximum blend allowed in these cases being 50%.
SAFs offer the potential to contribute to a net zero aviation industry given that lifecycle assessments have shown a possible 80% CO2 emission reduction from their use. According to SkyNRG, SAFs can improve fuel efficiency by 1–3%, as well as offering a 90% reduction of sulphur oxide and particulate matter emissions, leading to a lower formation of contrails.
Unfortunately, SAFs are not widely available and the current production capacity is sufficient for 0.01% of worldwide jet fuel demand. In addition, current costs are likely to be prohibitive for commercial uptake. The cost of bio-based fuels is estimated as being 3–10 times that of fossil jet fuel according to industry sources.
The European Commission is currently preparing a legislative proposal for a SAF blending mandate in order to boost their production and uptake in Europe, the ReFuel EU Aviation initiative. You can find ERA’s latest position here.