A Technoeconomic Model for Estimating Costs of Harvesting and Debarking Shrub Willow

Abstract

Highlights Technoeconomic analysis helps increase understanding of the potential of shrub willow debarking and provide assessment of economic opportunities. Harvest and transport costs are increased by debarking and account for more than 50% of total costs. The fraction of clean wood material is higher when shrub willow is harvested during the dormant season. Energy to break the wood-bark bond is almost five times higher in the dormant season than the growing season. High yield of willow biomass, high wood fraction, and high field capacity have a positive influence on profitability. Abstract. A technoeconomic model was developed for integrated debarking/harvesting of shrub willow that assesses the costs associated with debarking of willow and provides a platform for estimating the minimum selling price (MSP) for separated bark material. Harvest and transport costs are influenced by the addition of a debarking process and accounts for more than 50% of the total costs of willow production. The estimated MSP for bark material is $24.53 Mg -1 when the willow biomass is harvested in the dormant season and rises to $28.65 Mg -1 when harvested during growing season. The fraction of clean wood material recovered during the dormant season harvest averaged to 72% compared to 66% in the growing season (for shrub willow cultivars in this study). Increasing the field size from 10 to 50 ha decreases MSP of bark by 47%. High yield (~26 Mg ha -1 ) creates a condition in which a producer can be profitable by selling clean wood material only (with positive NPV). Likewise, sensitivity analysis shows that under the conditions modeled in this study, shrub willow varieties with high wood fraction have a lower MSP for bark material; MSP for bark material approaches zero when the fraction of wood rises to 86.6%. Keywords: Biomass, Debarking, Shrub willow, Techno-economic analysis.