The report’s assessment of the prospects for biofuel as a decarbonisation option has some significant misunderstandings, although its overall conclusion – that the challenge of decarbonising aviation is huge – is correct.
Low carbon liquid fuels (SAF), because of their energy density, are the only option in the near term (before 2050) and for long haul flight will remain the most promising option beyond then. There are three basic feedstock options for producing SAF; waste oils and fats, solid wastes and waste industrial gases, and renewable electricity.
The report places great emphasis on SAF produced from energy crops and the land required to grow them. However, it is not anticipated that energy crops will be a significant source of feedstock for SAF production in the UK. Indeed crop-based SAF will not be eligible under the UK’s SAF Mandate, which will come into play in 2025.
The UK’s policy is to focus on procuring SAF from solid and gaseous waste streams, such as black bin bag waste and industrial off-gases. Although SAF made from waste oils and fats is cheaper, the supply of Used Cooking Oil (the main feedstock) is limited and is best used in decarbonising the heavier end of road transport (i.e. HGVs) and this will be the case for some decades to come. As zero carbon options become available, more UCO become available for use in aviation and maritime. Contrary to what is said in the report, Used Cooking Oil is always a waste and cannot be fed to animals. This is banned in the UK, and most of the world, on health grounds.
