Economic analysis of delivering switchgrass to a biorefinery from both the farmers' and processor's perspectives

Switchgrass for bioenergy production will require substantial storage. The first paper evaluates costs of various baling and on-farm storage systems by simulating the final delivered costs to the biorefinery under two representative soil types in East Tennessee and West Tennessee. Influences of the volatilities of switchgrass yield, diesel fuel price and nitrogen fertilizer price on delivered costs are considered. Results show that rectangular bales minimize cost if switchgrass is processed immediately after harvest. However, round bales minimize cost if switchgrass is stored without protection for 200 days before being transported to the biorefinery. The second paper evaluates from the processors' perspective the least cost delivery schedule for switchgrass to a biorefinery considering bale types and storage methods. A mixed integer programming model was used to optimize the year round switchgrass delivery schedule within 50 miles of the biorefinery in East Tennessee from the processors' perspective, while minimizing the annual costs of delivering switchgrass. The delivery is constrained by land availability, switchgrass yields, field days for harvest, and storage dry matter loss. Scenario analyses for different plant sizes, harvesting systems, existence of storage loss and equipment efficiency were done in this study. Results from the base model show that the delivered cost, which accounts for $0.73/gallon of ethanol produced, is almost twice the U.S. Department of Energy's National Renewable Energy Laboratory's goal for feedstock production in 2012.