Potential for biogas production from crop residues or dedicated crops in France

Abstract

Biogas production potential relies on two main aspects: organic resources suitable for anaerobic digestion and performance of the production pathway from an energy and environmental point of view. The paper presents a first evaluation of potential biogas production in France from agricultural land, involving crop residues (wheat, maize, rapeseed, sunflower) and crops devoted to biomass production (alfalfa, silage and maize). The evaluation at the national level and at the level of each of the 95 French departements shows a potential production of about 10.6 Mtoe/yr, 5.15 Mtoe /yr from crop residues and 5.5 Mtoe /yr from biogas crops. An environmental analysis was conducted on the territory of the GRCETA.SFA, concerning 143 farms in Aquitaine, Southwest of France. Energy use and greenhouse gas (GHG) emissions were estimated in different systems corresponding to the conditions in the case study area. Fodder Maïze and Grain Maïze were studied as substrate for biogas production. Direct and indirect energy use for biogas production is about 44% of net biogas energy production in biogas crop systems, and 26% in biogas production from crop residue. The mean value of GHG emissions is 30 kgCO2.GJ-1 gross biogas production from biogas crops, and 18 kgCO2.GJ-1 gross biogas production from crop residues. Other environmental impacts, although they are not quantified in the present work, are briefly discussed qualitatively.