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Aircrafts flying around the world will be fueled at different airports in different countries which means that international fuel specifications for sustainable aviation fuels (SAF) is a necessity.

It’s a matter of ensuring flight safety and minimizing risk of mishandling, but it is also necessary to avoid the need for implementing a varied mix of fuel delivering systems at high cost. Finally, the specifications ensure that today’s engines or aircrafts does not have to be redesigned to run on SAF.

The standard regulating the technical certification of SAF is ASTM D7566 that specifies which technologies and methods can be used when producing on spec SAF. Once produced the SAF can then be blended up to a maximum certified blending limit and be certified to ASTM D1655 which is regarded as conventional Jet A or Jet A1 kerosene.

30068 Topsoe SAF Report A4 forside

Expert perspectives on Sustainable Aviation Fuel


Several routes lead to SAF certification

At present, the focus is on SAF as a drop-in replacement to conventional jet fuel. ASTM standards do not allow SAF to be used neat today and use is mostly limited to a 50% blend, with a maximum of 10% in some cases.

There are currently seven approved technology pathways to produce drop-in SAF with the following blending limits:

SAF-Certification-Table 1

Co-processing is another option for decarbonizing and meeting the criteria for the Standard Specification for Aviation Turbine Fuels (D1655). Co-processing involves the simultaneous processing of fossil and renewable feedstocks. It allows you to convert renewable feedstocks into drop-in, ultra-low sulfur bio jet fuel at economically competitive prices as you can use existing refining, transport, and storage facilities.

SAF-Certification-Table 2


Benefit from the industry’s most advanced range of catalysts, process design and proprietary technology. As your partner in SAF we’ll collaborate to ensure the whole process is successful from take-off to landing. And, with proven solutions and references from renewable fuels projects across the world, you can be assured we’ll get you safely to your destination.

Knowledge Special: SAF TALKSTM

Sustainable Aviation Fuel (SAF) is recognized as the most important solution currently available to the aviation industry as it looks to drive down its CO2 emissions and lower its impact on the environment. SAF is presently the only sustainable alternative to conventional jet fuel but yet it currently provides just 0.1-0.15% of global jet fuel use.

So what will it take to get SAF use off the ground? In our special Topsoe SAF Talks Series, recorded at the December 2022’s SAF Summit in Copenhagen, we gathered global experts spanning the SAF value chain to share their opinions and latest insights.


Tell me how

Sandra Winter-Madsen

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