A Corn Stover Supply Logistics System

Abstract

We evaluated the economics, energy inputs, and greenhouse gas (GHG) emissions for a proposed field to facility corn stover logistics system. The system included collection and transport by round bales to local storages within 3.2 km (2 mile) of the field during the fall harvest period 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 and fossil energy consumption for delivering the bulk corn stover (15% moisture) to end users were $81/t ($74/ton) and 936 MJ/t, respectively. The total fossil energy consumption was equivalent to approximately 7% of the energy content of corn stover. The life-cycle GHG emission for heat and power applications was approximately 114 kg CO2e/t at 15% moisture or 8 g CO2e/MJ of dry matter 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.