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Economic and Environmental Analysis for Corn Stover and Switchgrass Supply Logistics
- Kaliyan, Nalladurai, Morey, R. Vance, Tiffany, Douglas G.
- BioEnergy research 2015 v.8 no.3 pp. 1433-1448
- Panicum virgatum, Zea mays, biomass, bulk density, corn, corn stover, cropland, energy, environmental assessment, fossil fuels, greenhouse gas emissions, greenhouse gases, grinding, harvest date, soil organic carbon, Midwestern United States
- Supply logistics systems for corn (Zea mays L.) stover and switchgrass (Panicum virgatum L.) with two collection methods, round bales and rectangular bales, are developed. A location in the US Midwest is assumed with corn grown on highly productive crop land and switchgrass grown on less productive land. Bales (15 % moisture wet basis) are stored at local storage sites within 3.2 km (2 mi) of the field at harvest time. Biomass is transported to an end user within a 48 km (30 mi) throughout the year. Round bales are converted to bulk product [bulk density of 240 kg m⁻³ (15 lb ft⁻³)] by tub grinding followed by roll-press compacting before truck transport. Rectangular bales are delivered by truck without processing. Total delivered cost is $97.70 Mg⁻¹ ($88.63 ton⁻¹) for corn stover and $137.87 Mg⁻¹ ($125.07 ton⁻¹) for switchgrass when delivered as a bulk compacted product. Total delivered cost is $90.25 Mg⁻¹ ($81.87 ton⁻¹) for corn stover and $128.67 Mg⁻¹ ($116.73 ton⁻¹) for switchgrass when delivered as rectangular bales. Life-cycle fossil energy consumption is higher for delivering switchgrass (9.9 to 13.8 % of energy in dry matter) than for corn stover (5.8 to 9.5 % of energy in dry matter). Excluding any potential change in soil organic carbon (SOC), life-cycle greenhouse gas (GHG) emissions are 59.2 to 99.8 kg CO₂e Mg⁻¹ for delivering corn stover and 231.8 to 279.6 kg CO₂e Mg⁻¹ for delivering switchgrass. The effect of change in SOC on the life-cycle GHG emissions for corn stover and switchgrass is discussed.