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The role of co-processing in aviation’s transition to a lower-carbon future

Release date:
August 2022
bp refinery Lingen, Germany, water in foreground
Although demand for sustainable aviation fuel (SAF) is expected to experience significant growth1, production is currently limited with only a handful of commercial plants available today. bp believes that co-processing SAF at existing refineries will help the sector as it transitions to a lower-carbon industry and builds dedicated and more efficient standalone units for SAF production.


Today, existing refineries can be used to co-process 5% approved renewable feedstocks alongside the crude oil streams to meet the requirements of the industry jet fuel standard ASTM D1655. bp’s Lingen refinery in Germany is already being used to co-process SAF.


Alternatively, SAF produced in standalone units (which are not currently widely available) would meet ASTM D7566 - the standard specification for aviation turbine fuel containing synthesised hydrocarbons. This is then blended with up to 50% conventional jet fuel and recertified as ASTM D1655. Encouragingly, ASTM is also exploring initiatives for 100% SAF.


The advantage of co-processing is that it doesn’t require the significant financial investment and time) that comes with building a new standalone facility. Relatively minor modifications are required to enable co-processing of SAF while standalone plants get up and running.   Also, these traditional facilities potentially have greater flexibility in feedstocks for the coming years of energy transition, being able to switch between co-processing and crude oil, to meet fluctuations in demand. There are currently around 600 refineries2 in the world. That’s a huge manufacturing resource in terms of the opportunity to help production today.


Given the bulk of our refinery experience to date has been based around crude oil, we are continually using this expertise as the foundation for building our knowledge and understanding around renewable feedstocks used for co-processing. Over the last decade we have gained greater understanding of what these feedstocks bring that is different to fossil fuels, as well as how this might impact our facilities and kit. This has placed us in a strong position to co-process SAF in the most efficient and economical way.


Another advantage of co-processing is that operators can be flexible in terms of increasing the volumes of renewable feedstocks while decreasing crude oil volumes. bp has launched an ASTM co-processing taskforce working alongside other industry experts to increase the limit of approved renewable feedstocks from 5% up to 30%. If successful, this approval would benefit the whole industry. It’s about finding a universal route to help the industry transition to a lower-carbon future. Ultimately, the aim would be to explore co-processing of up to 100% renewable feedstocks as reliance on fossil fuels diminishes in the future.


Let’s look and co-processing and standalone plants in more detail


When it comes to transporting feedstocks to refineries, this is typically done by rail, truck, or barge. For example, our refinery in Lingen can receive shipments by barge which enables feedstocks to be transported in bulk offering more competitive freight costs and in most cases lower carbon emissions compared to trucks. Once co-processed the optimum method for transporting SAF is via pipeline. This is a highly efficient, convenient, and safe way of supplying fuel to airports. Generally, aviation fuel in the US is supplied to airports using a network of pipelines3 and in Europe many existing refineries are well connected to efficient logistics solutions such as pipelines or rail. Standalone plants (depending on where they are located and the supply routes for such plants) might not be so well connected. Care will be required to optimise this aspect, balancing sustainable feedstock source and distance to the aviation market.


One of the advantages with a standalone plant is that it produces 100% renewable SAF, which can be transported neat before being blended with conventional jet fuel.  Co-processed fuel, on the other hand, produces a finished product but with a much lower SAF blend as it only contains up to 5% renewable feedstocks. This highlights the importance of solutions such as mass balancing and book and claim systems enabling customers greater access to the lower carbon benefits of co-processed SAF. The latter enables customers to access the benefits of SAF without being physically connected to the supply site, and high volumes of conventional jet fuel (blended with SAF) don’t have to be transported in inefficient ways. Success of the proposed 30% co-processing approval would clearly benefit all.


Another challenge fuel suppliers face is that to qualify for tax credits and other financial incentives some jurisdictions require proof of the renewable carbon content in aviation fuel, using third-party verification through C-14 testing. This tests for carbon from recently living sources such as plants and animals. However, with the range of renewable feedstocks continually evolving C-14 is not an effective test method for all possibilities, for example municipal solid waste. Similarly, when looking at green hydrogen as a feedstock, carbon-14 testing would not be appropriate as no carbon is present in the stream. Equally processes may benefit from renewable energy and direct carbon capture again highlighting the depth of understanding required beyond a simple test method.  Given SAF from standalone plants is produced from 100% renewable feedstocks the requirement for C-14 isn’t necessary and we anticipate this resource-intensive test method will eventually be removed for standalone produced SAF. We believe that feedstock traceability and lifecycle reduction measures are a more efficient and cost-effective way of measuring and accounting for the carbon footprint in co-processed SAF too, and as such, we would like to see C-14 testing replaced by these in all circumstances.


A combination of co-processing and standalone units is required to meet industry targets


As the aviation sector continues to explore opportunities to scale up the production of SAF in the most economical and efficient way, bp considers that co-processing has an integral role to play. However, we also believe that co-processing on its own won’t be enough to meet increasing SAF demand. Standalone units will also be required to ramp up production. Building on its refinery footprint in the near-term future, bp anticipates investing in five major biofuels projects, including three adjacent to existing refineries and the conversion of up to two bio-refineries.


It’s only by combining the expertise and resources found in existing refineries with new processes and standalone plants that the industry will be able to ensure SAF is supplied at scale, not just in the short term, but up to and beyond 2050.



1 ATAG Waypoint 2050 report:



2 McKinsey Energy Insights:



3 Airlines for America report:



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