Cob Biomass Supply for Bioenergy In the North Central USA.

Corn (Zea mays L) cobs are being evaluated as a potential bioenergy feedstock for combined heat and power generation (CHP) and conversion into a liquid biofuel.  The objective of this study was to determine corn cob availability in north central U.S. (Minnesota, North Dakota, and South Dakota) using existing corn grain ethanol plants as a proxy for possible future co-located cellulosic ethanol plants.  Current available cob production (2008-2009) estimates averaged 9.38 Tg and 6.40 Tg using a 80 km radius area and 40 km radius area, respectively, from existing corn grain ethanol plants.  Significant radius area overlap (53% overlap for 40 km radius and 86% overlap for 80 km radius) exists for cob availability between current corn grain ethanol plants in this region suggesting possible cob supply constraints for a mature biofuel industry.  Economic and feedstock logistics models need to account for possible supply constraints under a mature biofuel industry. A multi-feedstock approach will likely be required to meet multiple end user renewable energy requirements.