Production of liquid fuels by thermoconversion of lignocellulosic biomass: evaluation for the future French energy system.

Summary Biomass is expected to represent a growing share of the world's primary energy consumption and the search for the optimization of the use of such a resource, abundant but not plethoric, is essential. This thesis raises the question of the place, in this optimization, of second generation biofuels, by focusing on the thermochemical route, and more particularly on the synthesis of liquid fuels by the Fischer-Tropsch process, which makes it possible to obtain hydrocarbons of the naphtha, kerosene and gas oil type. To address this issue, an evaluation approach is proposed, which includes: - an evaluation on the scale of the processes, applied to a family of about one hundred options, - a systemic approach to assess the insertion of the processes in the future French energy system. The implementation of this evaluation approach shows how : - thermochemical processes for the production of second-generation biofuels can combine biomass and other less limited primary energies to maximize the transfer of renewable carbon from biomass into liquid fuels, but at costs that remain high. - The answer to the question of how to optimize the use of biomass and the place to be given to biofuels depends strongly on the global evolution of the energy system and the feasibility of CO2 storage.