Impact of probability of working day on planning and operation of biomass feedstock production systems

Unfavorable weather can significantly impact the production and provision of agriculture-based biomass feedstocks such as Miscanthus and switchgrass. This work quantified the impact of regional weather on the feedstock production systems using the BioFeed modeling framework. Weather effects were incorporated in BioFeed by including the probability of working day (pwd) parameter in the model, which defined the fraction of days in a specific period such as two weeks that were suitable for field operations. Model simulations were conducted for Miscanthus and switchgrass for values of pwd between 20 and 100% and intended biorefinery capacities between 1000 and 5000 Mg d ^-1; and the impact on total cost and farm machinery requirements was quantified. Results indicated that using production and provision systems designed assuming 100% pwd for lower pwd values increased the cost exponentially by up to 64% for Miscanthus and 85% for switchgrass. It also decreased the supportable biorefinery capacity for the collection region by up to 60%. If the systems were instead optimized for specific values of pwd, the original biorefinery capacity was maintained and the total cost increase was less than 5%. The resulting optimal systems required up to 40% higher investment in farm machinery. For Illinois, production systems designed for regional pwd values required a 34% increase in farm machinery investment for Miscanthus while only a 12% increase for switchgrass. Initiating Miscanthus harvesting in November instead of January reduced the farm machinery investment increase to 17%, which suggests that such an alternative should be rigorously evaluated.