(604k) Conventional Versus Advanced Depot Biomass Supply Systems for a Thermochemical Conversion Process and Biorefinery Sizing: Life-Cycle Assessment and Techno-Economic Analysis

Authors: 
Tan, E. C. D., National Renewable Energy Laboratory
Jacobson, J. J., Idaho National Laboratory
Cafferty, K. G., Idaho National Laboratory
Dutta, A., National Renewable Energy Laboratory
Searcy, E., Idaho National Laboratory

A cross-functional team has recently investigated issues around biorefinery capacity, conversion process techno-economics, environmental sustainability, and reliable feedstock logistics [1]. The study focuses on analyzing conventional versus advanced depot biomass supply systems for a thermochemical conversion process and biorefinery sizing based on woody biomass. This presentation will be based on this study and will highlight the results of techno-economic analysis and environmental sustainability assessment including life-cycle greenhouse gas (GHG) emissions. Investigations of the feedstock supply system and biorefinery sizes reveal that both the conventional and advanced depot biomass feedstock supply systems display good economies of scale with increasing biorefinery size; however, the conventional system cannot supply the volumes required for large biorefineries (i.e., greater than 5000 dry metric tonne per day). Although the overall costs increase slightly for the advanced logistic supply systems, there are storage and conversion benefits from the ability to mitigate moisture and ash content in the feedstock. In contrast to process economics, marked differences in environmental sustainability are observed between conventional logistics and advanced logistics design concepts in terms of life-cycle GHG emissions. Specifically, when using natural gas as the drying fuel for the advance depot supply system, the life-cycle GHG emissions are approximately three times greater than that for the conventional logistics. Furthermore, for the conventional case the life-cycle GHG emissions per gallon of fuel increased with the biorefinery size because of  increased transportation fuel usage with larger collection radius, whereas for the advanced depot case life-cycle GHG emissions per gallon of fuel was essentially independent of biorefinery capacity.

[1] Muth, D.J., Langholtz, M.H., Tan, E.C.D., Jacobson, J.J., Schwab, A., Wu, M.M., Argo, A., Brandt, C.C., Cafferty, K.G., Chiu, Y.-W., Dutta, A., Eaton, L.M., and Searcy, E.M., “Investigation of thermochemical biorefinery sizing and environmental sustainability impacts for conventional supply system and distributed pre-processing supply system designs,” Biofuels, Bioproducts and Biorefining, Article first published online : 31 MAR 2014, DOI: 10.1002/bbb.1483.