Supply costs, energy use, and GHG emissions of biomass from marginal lands in Brittany, France

International audienceGrowing energy crops on marginal lands is an option to increase current bioresources while avoiding the food vs fuel dilemma. Yet, little is known about the extent and characteristics of marginal lands, and about how growing energy crops on such lands will impacts productivity, supply chains, and the environment. This study combined a geographic information system, a crop growth model, life cycle assessment, and a logistics model to (i) quantify and map marginal lands (ii) estimate the yields of miscanthus grown thereon (iii) assess the impact on supply chain and the environment of miscanthus from marginal lands in Brittany. Three miscanthus harvest forms (chips, bundles, and bales) and three logistics scenarios (no storage, one storage point, and two storage points) were studied. It showed that 57544 ha of marginal lands are available in Brittany and that rooting (55%) and salinity (34%) were the dominant marginality factors of these lands. Miscanthus yields on these lands varied from 0 to 21 t DM ha-1 y-1, depending on marginality constraints. Despite the low energy use (311-604 MJ t-1 DM) and GHG emissions (6-19 kg CO2-eq t-1 DM), the delivery costs were too high (81-108 euro t-1 DM). Bales were the cheapest and most environmental-friendly biomass form, as was the logistics configuration with no storage point. Sourcing biomass from marginal lands offers a solution for sustainable biofuel production in Brittany. However, economic incentives are needed to encourage production on marginal lands given the high delivery costs of biomass