Evaluation of a Modular System for Low-Cost Transport and Storage of Herbaceous Biomass

A conceptual system adopting features from cotton, silage, and container shipping systems was evaluated between 2008 and 2011. The evaluation included both simulations of the anticipated full-scale system and field trials of forming, transporting, and storing biomass modules containing energy sorghum. The simulations utilized Integrated Biomass Supply Analysis and Logistics (IBSAL) and incorporated the anticipated module forming machine that would operate in partnership with a forage harvester, as well as a machine to load the modules onto a flatbed semi-trailer. When compared to the DOE target for logistics costs of $38.59/Mg, the estimated cost was lower for distances up to 80 km. Field results were promising, with biomass modules of up to 5.2 Mg formed, stored for up to 12 months, loaded on a truck in 2 min or less, and transported for 96 km with no significant change of shape or size. Difficulty in field drying of energy sorghum was consistent over 3 years of harvest, as was the ability to use field drying in windrows without increasing the ash content of the biomass. The manually formed module packages did not maintain an anaerobic environment throughout the storage period, and excessive biomass degradation occurred. In addition, the dry matter density in the modules was approximately 180 kg/m³ rather than the 240 kg/m³ targeted in the simulation. Despite the conceptual evaluation not achieving all the desired features, these studies demonstrated the economic and logistical advantages of a system based upon large packages of chopped biomass.