Used cooking oils are unfit to fly from a climate policy perspective

On 14 July 2021, the European Commission presented its "Fit-for-55" package.  Part of the package is a legislative proposal also known as the “ReFuelEU” Aviation initiative. This proposal aims to ensure that air transport continuously reduces its greenhouse gas (GHG) emissions through an increasing use of Sustainable Aviation Fuels (SAF).

Of course, aviation must also make a contribution to climate protection.  But the understandable effort to make air traffic more climate-friendly must not lead in actionism. Especially since there is a limited number of sustainable fuel alternatives to decarbonize aviation.

However, the European Commission's proposal gives exactly this impression. From 2025, a gradually increasing blending mandate for SAF is to be introduced. The mandate is currently designed with a limited number of sustainable fuel options.  A very limited number.  From today's perspective, there is only one option that could be used in significant quantities from 2025 and for many years beyond: aviation fuel from waste oils.  Made from waste and residue oils according to the so-called "HEFA" process (Hydroprocessed Esters and Fatty Acids).

At first glance, this  option seems promising. Fuels from wastes and residues are widely accepted by the public. However, wastes and residues are only available to a limited extent. And they are already largely used elsewhere. This also applies to used cooking oils and other waste oils, such as animal fats. These are usually processed into waste-based biodiesel, renewable a fuel that reduces GHG emissions by over 90%. Added to fossil diesel, waste-based biodiesel helps to make a significant contribution to climate protection in road and maritime fuel consumption. Already in 2018, 3.6 million tons of CO2-equivalent emissions were saved through the use of waste-based biodiesel in German roads. With waste-based biodiesel, the existing vehicle fleet can significantly contribute to climate protection.

Waste-based biodiesel is not suitable for air transport. Its cold flow properties are not sufficient to support it.  However, waste-based biodiesel can help to reduce GHG emissions from inland and maritime transport.  This has been shown in numerous practical tests worldwide.

By introducing a mandate for the use of sustainable aviation fuels, the European Commission would create a huge additional demand for waste oils. In doing so, it is setting the course for the diversion of waste oils, which are now used for biodiesel production, into aviation fuel production. The reasons are easy to understand. There is not a sufficient amount of waste oils in the EU to maintain today's biodiesel production and simultaneously produce the amount of sustainable aviation fuels that the proposed mandate would require. And in addition, it would be a competition for waste oils with unequal weapons. The blending mandate envisaged by the European Commission would give a handful of producers of HEFA aviation fuels a significant competitive advantage in the raw materials market over the large number of medium-sized producers of waste-based biodiesel. The result would be "raw material cannibalization" par excellence.

It is far more energy-intensive to produce aviation fuels from waste oils than biodiesel. In addition, the fuel yield in aviation fuel production is worse than in biodiesel production. Overall, an aviation fuel from waste oils reduces GHG emissions by around 75%. This is shown by the study "Conversion efficiencies of fuel pathways for Used Cooking Oil" by studio Gear Up from February 2021.  The Federal Environment Agency also sees the higher climate and environmental benefits of used cooking oils in biodiesel production (transesterification). This emerges from the UBA texts 09/2021 "Determination of criteria for high-quality other recycling possibilities of biowaste" from January 2021.  A diversion of waste oils from biodiesel production to aviation would therefore increase GHG emissions when considering the entire transport sector, and thus run counter to the climate targets of the European Commission.

An efficient climate policy for aviation must therefore first and foremost be a driver of innovation. It must promote new, advanced fuel options, such as e-kerosene or alcohol-to-jet fuels. It must focus on the use of previously unused wastes and residues. A prioritization that is more important today and also serves as a security of supply.  A holistic view of the transport sector is also indispensable if the EU is to achieve its climate targets.  But the European Commission's proposal fails to address the real issue: climate change mitigation.

Supplementary graphic from studio Gear Up study (2021)


Studie „Conversion efficiencies of fuel pathways for Used Cooking Oil”

UBA Texts 09/2021 "Determination of criteria for high-quality other recycling possibilities of biowaste"

Detlef Evers, Managing Director, Mittelstandsverband abfallbasierter Kraftstoffe e.V. (MVaK)

Original piece published in Deutsche Verkehrs-Zeitung (DVZ), a German transport and logistics newspaper.

May 2022

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