Economics of a coordinated biorefinery feedstock harvest system: lignocellulosic biomass harvest cost

Abstract

Abstract A potential advantage of lignocellulosic biomass gasification–fermentation technology is that a variety of feedstocks, including agricultural residues, native grasses, introduced perennials, and dedicated energy crops may be gasified by the same facility. Since harvest windows differ across species, gasification–fermentation technology would enable the use of specialized harvest and collection machinery throughout many months and reduce the fixed costs of harvest machinery per unit of feedstock. This study was conducted to determine the cost to harvest lignocellulosic biomass for use as biorefinery feedstock, and to determine the potential economies of size that might result from a coordinated structure. An agricultural machinery cost computer program was used to determine which specific type of machines would result in the lowest costs at intensive levels of use. A machinery complement estimator was used to design a coordinated set of machines and estimate costs for owning and operating the machines. The designed coordinated harvest unit includes ten laborers, nine tractors, three mowers, three rakes, three balers, and one bale transporter. The cost for mowing, raking, baling, gathering, and stacking in-field was estimated to be from $11.26 to $14.01 Mg −1 depending upon biomass yield. A biorefinery with an annual feedstock requirement of 910 Gg yr −1 would require approximately 18 harvest units and an average machinery investment of $11 million. Additional research is necessary to determine the cost to procure material from the landowner, the cost to store, storage losses, and the cost to transport feedstock from in-field stacks to a biorefinery.