UBC Theses and Dissertations
Biorefinery feedstock availability and price variability : case study of the Peace River region, Alberta Stephen, James Duncan
The purpose of this research was to quantify feedstock supply risk over the lifetime of an agricultural residue-based (straw and chaff) biorefinery and to determine the range of delivered prices. The Peace River region of Alberta was used as a case study for analysis, with a geographic information system utilized for data analysis. Inter-year availability of crop residues was highly variable over the 20 year period under study, which created significant differences in the delivered price of feedstock between minimum, average, and maximum availability scenarios. At the four primary study sites (Fahler, Grimshaw, Peace River, and Sexsmith), the range was from double the average availability for the maximum scenario to zero biomass available for the minimum scenario. Biomass availability is a function of grain yield, the biomass to grain ratio, the cropping frequency, and residue retention rate used to ensure future crop productivity. Using minimum, average, and maximum supply scenarios, delivered price was determined using the dynamic (time-dependent) Integrated Biomass Supply Analysis and Logistics (IBSAL) simulation model. Five biorefinery capacities, ranging from 50,000 to 500,000 tonnes of feedstock per year, were analyzed. Since no biomass was available to model in true minimum years, a simulated minimum of half the average availability was used. Delivered cost, including harvest and transportation, for the 50,000 t plant ranged from $24.01 t-1 for the maximum availability scenario at the Sexsmith site to $42.63 t-1 for the simulated minimum scenario at the Fahler site. The range for the 500,000 t plant at the Sexsmith site was $41.78 for the maximum availability and $70.98 for the simulated minimum availability. As no biomass is available (and hence the true cost is unknown) in some years, storage strategies must be implemented and alternate feedstock sources identified to supply biorefineries in low-yield years. Since feedstock cost is a large component of total operating cost of a biorefinery, feedstock supply variability and delivered cost inconsistency should be primary decision criteria for any future biorefinery projects.
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