Blending short rotation coppice poplar with wheat straw as a biorefinery feedstock in the State of Washington

Abstract To ensure an uninterrupted feedstock supply, commercial-scale cellulosic biofuel production facilities must consider using more than one type of biomass; this paper considers the use of poplar and wheat straw. Short rotation coppice poplar will be a competitive feedstock for future biorefineries because of the low cost and year-round availability. Wheat straw is seasonally available in Washington State and can potentially be added to woody biomass to fortify the feedstock supply chain when economically advantageous. In this study, blending of poplar whole-tree chips (PC) from short rotation coppice and wheat straw (WS) at the ratios of 25%/75%, 50%/50%, and 75%/25% were investigated for sugar conversion. Overall, the blends achieved up to 21% (90 kg/tonne) higher monomeric sugar yield than using PC as the sole feedstock. Economic analysis suggests that blending could be feasible for ethanol production provided WS can be obtained at a reasonable price ($60–$69/tonne). Blending of PC and WS allows feedstock flexibility and mitigates supply risks associated with biomass shortage, while maintaining a consistent process, robust product yields, and a stable product cost.