D.5.3 – A new logistics model and its application to case-study value-chains

Little is currently known about the amount and spatial distribution of marginal lands, as well as the economic and environmental impacts of regional supply chains of biomass sourced from marginal lands. Here we combine three tools: GIS data layers, CERES-EGC and LocaGIStics to (i) quantify and map marginal lands in Brittany (France), (ii) simulate yields of miscanthus on these lands, (iii) assess the economics and environmental impacts of a biomass supply chain from these crops. Three miscanthus harvest forms (chips, bundles, and bales) and three supply scenarios (no intermediate storage, one storage point, and two storage points) were studied. We found a total of 57,544 ha of marginal land in Brittany, which are suitable for miscanthus production. The prominent marginality constraints were rooting (55%) and salinity (34%). The simulated yields of miscanthus yields on these lands varied from 2 to 19 tons dry matter (DM) ha-1y-1 and were much lower in saline than in stony soils. The farm-gate production costs of miscanthus on these lands ranged from 53 to 104 € DM ton-1 whereas energy use varied from 199 to 431 MJ ton-1, depending on crop yields, management and harvesting methods. The farm-gate GHG emissions of miscanthus (-71 to 116 kg CO2 ton-1) showed that the crop was a net GHG sink in some fields, while in others it represented a small source of GHGs compared to other similar biomass feedstock. The logistics models showed it costs 91 to 121 € DM ton-1 to supply a biorefinery plant with a 40 kton yr-1 biomass processing capacity. The associated environmental impacts were an energy demand of 492 to 1,290 MJ DM ton-1, and GHG emissions ranging from 11 to 66 kg CO2 DM ton-1, depending on the harvest form and the storage scenario. Miscanthus was economically and environmentally more viable when delivered as chips than as bundles or bales in all scenarios. Chips should thus be favoured over bundles and bales for short transport distances. A deeper analysis of the supply chain showed that biomass production, transport and storage dominated the total delivery costs, energy use, and GHG emissions. Compared to another feedstock type such as agricultural residues, miscanthus from marginal lands presented a competitive advantage, with a lower risk in terms of biomass sourcing. This study improves our understanding on the distribution of marginal lands and on the supply chain of miscanthus in Brittany. It also provides a proof-of-concept regarding the logistics of supplying biomass from marginal lands, which are highly challenging due to their lower production potential and the uneven spatial distribution