A biomass supply logistics system

We evaluated a corn stover logistics system that included collection and transport by round bales to local storages within 3.2 km (2 miles) of the field during the fall harvest period. This stage was followed by processing at the local storage sites throughout the year using mobile units which converted the bales to bulk material by tub-grinding and roll-press compacting to 240 kg/m³ (15 lb/ft³) to achieve 22.7 t (25 ton) loads for truck delivery to an end user within a 48 km (30 mile) radius. The total cost, fossil energy consumption, and greenhouse gas (GHG) emissions for delivering the bulk corn stover to end users were $85/t ($77/ton;), 936 MJ/t, and 114 kg CO₂e/t, respectively, including nutrient replacement. The total fossil energy consumption was equivalent to approximately 7% of the energy content of the biomass. The life-cycle GHG emissions for heat and power applications were approximately 8 g CO₂e/MJ of dry corn stover including emissions for logistics and combustion, but excluding those associated with soil organic carbon (SOC) loss. Our estimates show that as a fuel for heat and power applications, corn stover reduced life-cycle GHG emissions by factors of approximately 8 and 14 compared to natural gas and coal, respectively.