Biomass is already ensuring roughly 10% of the primary energy supply in the world, i.e. 1 G toe from 11 Gtoe. Wood is the main contributor. A large proportion of this biomass is used nder poor conditions and contributes to deforestation. Human food represents the equivalent of 600 Mtoe, and clearly the energy demand might threaten a proper access to food if biomass is extensively used for energy production. Biomass used for firing boilers can be provided to a large extend by waste (waste from wood constructions, biogas from organic waste). This is not the case with biofuels, which are produced from sugar extracted from sugar plants or derived from starch crops. From 419 Millions tons of cereals produced in 2009 in United States, 119 Millions have been transformeinto ethanol for producing biofuels. This production of biofuels competes then directly with food needs. For this reason, R&D work is aiming at the production from biomass fraction which cannot be used for food, such as lignocellulosic biomass. Attemps are made also fopr prodicing biofuels from microalgae in bioreactors. These different options are costly and it is still difficult to know if they might be developed at a large scale and when.
C’est dans le domaine de l’énergie que la demande pourrait être
potentiellement la plus importante. De toutes les énergies renouvelables, la
biomasse est celle qui est la plus facilement substituable aux énergies
fossiles. En effet l’énergie issue de la biomasse est utilisée sous forme de
combustibles solides, liquides ou gazeux, qui peuvent remplacer dans certaines
conditions des combustibles fossiles tels que le charbon, le pétrole ou le gaz
naturel.
