Supply Chain Model to Compare the Biorefinery Economics and Environmental Performance of Baled and Pelleted Biomass System

A supply chain model for an economic and environmental assessment of pelleted and baled corn stover was developed based on minimizing the total cost of the supply system with the optimum location and capacity of each biomass processing facility. The model was applied on a county-level basis in the state of North Dakota, USA. Two different biomass availability scenarios were considered where either 35% or 50% of biomass (corn stover) was available for collection from farms and processing at the biorefinery. All the ethanol produced was assumed to be sold. Pelleted biomass system requires a pelleting step either at a collection facility or at the biorefinery itself, while baled biomass is ground at the biorefinery. The economic analysis of the alternate supply systems showed that using pelleted biomass reduces overall supply chain cost and minimum ethanol selling price by almost 12% compared to baled biomass system. The largest costs were associated with biorefinery processing while transportation had a relatively minor contribution to the total cost. Similarly, the environmental greenhouse gas emissions were also lower for the pelleted biomass supply system compared to baled biomass system. The 35% case scenario (near term) and 50% case scenario (future term) showed similar economic and environmental greenhouse gas emissions.