How sustainable are advanced and waste biofuels?

According to the EU’s green fuels law, the Renewable Energy Directive (RED III), advanced and waste biofuels are distinguished between materials requiring a more advanced processing (Part A), such as straw and forestry residues, and oils that are easier to extract, such as used cooking oil and animal fats (Part B).

Several EU climate policies mandate the use of advanced and waste biofuels. The main policy tool is the EU’s green fuel laws (Renewable Energy Directive - RED). Fuel EU and ReFuel EU regulations for shipping and aviation respectively also provide support to these biofuels.

In recent years, the use of advanced and waste feedstocks has grown significantly, slowly replacing food crop biofuels and reaching 40% of all biofuels consumed in 2022.

The EU’s double-counting mechanism means Annex IX biofuels are counted twice in green energy targets. This means that Annex IX biofuels made up almost 60% of the overall biofuels' contribution to the transport target. Biofuels overall account for close to 7% of transport energy demand in the EU.

Despite being increasingly advertised as a green solution, using advanced and waste materials to produce biofuels comes with significant challenges.

Burning biomass still releases greenhouse gas emissions and it can take years, or decades in the case of wood, for the emitted carbon to be captured again.

Incentivising the use of primary forestry residues, such as bark or tree tops, essential to regeneration and biodiversity, will likely result in increased pressure on European forests.

Using land for growing biofuels crops has proven to be highly inefficient and has led to land-use change and deforestation. Intermediate and other energy crops are considered “advanced” and will likely increase pesticides, fertilisers and water usage.

What’s more, most advanced biofuels feedstocks are already employed in other sectors, such as sawdust for material applications or crude glycerine in the chemical industry. Diverting these feedstocks may lead to indirect emissions if their existing applications start to use less sustainable materials, potentially cancelling out any savings compared to fossil fuels.

While used cooking oil or animal fats categories 1 and 2 can be sustainable feedstocks, domestically available volumes are very limited and already largely processed as biofuels.

Other feedstocks such as municipal and industrial waste or sewage sludge might also be deemed sustainable, but processing technologies are still very uncertain today and waste volumes should decrease in the future thanks to better recycling and reusing.

Altogether, truly sustainable biofuels are expected to be scarce and will not be enough to meet ambitious EU mandates for decarbonising the transport sector in the long run. Renewable hydrogen fuels will be essential to decarbonise the aviation and shipping sectors and zero-emissions vehicles, especially electric, are the best available options to decarbonise the road sector.

The incentivisation of waste biofuels drives up their value, making them susceptible to fraud. The EU’s long-awaited Union Database is supposed to improve transparency along the biofuels supply chain, however, the certification processes' inherent weaknesses make it unlikely to stop fraud on its own. Instead, the EU and its member states must take other steps to combat fraud effectively and ensure truly sustainable feedstocks are used for the production of biofuels.