A Comparative Analysis of the Economics and Logistical Requirements of Different Biomass Feedstock Types and Forms for Ethanol Production

Abstract

Bioenergy in the form of heat, power, and transportation fuels is one of the most sustainable renewable means that can meet our rapidly growing energy demands. While the technology and economics of transporting, storing, and handling grain for the production of ethanol is well developed and understood, commercial production of ethanol from cellulosic feedstocks is yet to be established. The primary objective of this study was to analyze the technical requirements and economics of transporting, storing, and handling lignocellulosic biomass feedstocks for the production of ethanol in five different plant sizes between 151.4 and 757.1 million liters per year (MLPY). The overall cost per liter of the feedstocks before conversion to ethanol was determined. The five feedstocks investigated were corn grain, bales of corn stover and switchgrass, and pellets of corn stover and switchgrass. The results of the spreadsheet analysis showed that among the biomass feedstocks considered, the cost per Mg of transporting switchgrass pellets was the least for bigger plant sizes and for smaller plant sizes the cost of transporting bales and pellets were comparable. Because of pelleting, the reduction in per Mg hauling cost increased from approximately 6%-7% for 378.5-MLPY plant to 9%- 10% for 757.1-MPLY plant. The storage cost per Mg of bales was almost three times that of pellets for plant sizes above 227.1MLPY. Of all the feedstock types, the total cost per liter of corn stover pellets before conversion to ethanol was the lowest for all ethanol plant sizes, including corn grain. The analysis showed that pellets could be economically beneficial to either green field cellulose ethanol plants or existing corn grain plants transitioning to commercial fuel ethanol production.