Biofuels, fuels derived from the transformation of biomass, can offer a promising carbon-free alternative to current fossil hydrocarbons, particularly in sectors where electrification is not feasible in the short term, such as aviation, maritime, industry or heavy transport. They also make it possible to overcome strategic dependencies on oil-producing countries. Their current use, which is preferred for cars in many countries, is gradually being realigned towards other mobility sectors. Their production now amounts to 4.6 EJ per year, or 2.3% of the energy generated from oil.
Biofuels come in 3 generations, with different levels of maturity:
1st generation: they come from biomass that is generally edible for humans or animals, rich in sugar. (TRL 8-9)
2nd generation: they come from biomass residues intended for food, food scraps, or inedible biomass, of which lignocellulose is used in particular. They are now in the development phase. (TRL 6-8)
3rd generation: they come from seaweed, their use is still in the testing phase. (TRL 3-4)
2nd and 3rd generation fuels are called “advanced biofuels”.
Biofuels may have externalities that are sometimes few, or not sufficiently taken into account (water, biodiversity, soils, etc.), but which are lower for the second generation.
First generation fuels have long been favoured and present a major drawback: competition with human food. It is this criterion that has led legislation to evolve in order to favour more sustainable alternatives. The 2018 European RED II directive sets a target of 14% of renewable fuels in transport by 2030, with a ceiling of 7% of first-generation biofuels and sets strong sustainability goals, in particular on land use and regeneration criteria. Criteria for reducing greenhouse gas emissions are also set, by calculating in a well to wheel life cycle analysis, with a minimum reduction of 65%. In aviation, the ReFuelEU Aviation standard will require 5% SAF (sustainable aviation fuel) by 2030, which would represent 2.3 million tons of SAF, against the current 0.24 million tons. Questions are being raised about the availability of biofuels to meet ever stronger needs and standards. Indeed, the strong competition in biomass with other sectors could make it difficult to access biofuels, in addition to a rise in prices. This is evidenced by the fact that the European Union currently uses 7 million tons of used cooking oil to produce biofuels... 4 times more than the maximum potential for recovering used oil in Member States! Unfortunate consequence: it has to import them from Asia. Indeed, before being used for biofuels, biomass is also necessary for plastics, construction...
Although tinged with considerable uncertainty, the projections underline that at the European or global level, choices to prioritize uses will be necessary, even while increasing production yields.
These uncertainties around availability are reinforced by strong variabilities specific to certain sectors: the replacement of thermal vehicles by electric vehicles could relax availability for other sectors. The technological choices made by heavy transport could intensify tensions on resources. Indeed, the maritime and aviation sectors can base their transition on e-fuels derived from green hydrogen or on the use of biomass. These strategic choices that are being made today and in the years to come will strongly influence demand in these sectors, as well as the opportunities for innovation and transfer to more available technologies.
Image Credit: Transport Express