Are biofuels really sustainable?

Derived from plant, animal, or recycled waste sources, biofuels are one of the few solutions that can be immediately deployed to reduce the carbon footprint of aviation, shipping, and heavy-duty transport. Unlike other renewable energy sources, they can be blended with existing fossil fuels without requiring major modifications to engines or infrastructure. According to the International Energy Agency, biofuels could provide up to 27% of the fuel used in global transportation by 2050.

In the road transport sector, although electrification is becoming dominant, biofuels—already available in forms such as E10 or B7—offer a complementary solution to accelerate decarbonisation. In aviation, sustainable aviation fuels (SAF), which can be directly integrated into kerosene, are considered a priority. However, the outlook remains uncertain for maritime transport, one of the most complex sectors to decarbonize due to the wide variety of vessels.

A controversial energy and environmental balance

While biofuels can significantly reduce CO₂ emissions, their impact depends heavily on the type of feedstocks used and the production processes involved. Today, only first-generation biofuels (derived from food crops) are available at large scale. However, their production is energy- and resource-intensive and competes with food agriculture by using land, water, and agricultural inputs. These concerns have led the European Union to restrict their use and impose strict sustainability criteria under the RED II and RED III directives (see box).

Towards more sustainable biofuels

For biofuels to truly contribute to the energy transition, their environmental footprint must be reduced and their impact on food security minimised. One of the main levers is to use feedstocks that do not compete with food uses, such as organic waste, forestry or agricultural residues, or crops grown on degraded land. These so-called second-generation biofuels enable circular resource use and can achieve greenhouse gas emission reductions of around 80% to 90% compared to fossil fuels⁽¹⁾. Several initiatives are advancing in this area, such as the BioTfueL consortium and the Futurol project in France, which convert lignocellulosic biomass (straw, forestry residues, dedicated crops, etc.) into bioethanol through thermochemical processes.

At a more experimental stage, third-generation biofuels are derived from microalgae or CO₂ capture. They offer high energy yields and potential for carbon sequestration, but their industrial-scale deployment remains a long way off. Several industrial players are involved in these efforts, including TotalEnergies, which participates in various R&D projects in partnership with research institutions such as the CEA (France), the Qingdao Institute of Bioenergy and Bioprocess Technology (China), and Wageningen University (Netherlands) through the European Magnificent project.

The footprint of biofuels can also be reduced by optimising their transformation processes, such as refining, fermentation, or gasification. Several approaches are being explored, including electrifying production units, using less energy-intensive enzymes, and recovering waste heat. These innovations help improve the overall energy efficiency of the life cycle of advanced biofuels.

While biofuels are only a partial alternative to fossil fuels, the European Union is unlikely to achieve its energy transition objectives without them. Their development—particularly in advanced forms—is part of a broader transformation of industrial sectors that is still in its early stages.