Willow supply strategies to energy plants

摘要

The main objective of this study was to develop minimum cost supply strategies for willow energy plants (two plant sizes: 0.5 and 30 MW_e, two energy conversion technologies: combustion and gasification). Time span between harvest and energy conversion varied from 1 to 12 months. For a realistic comparison, different supply chains were based on the same initial characteristics (i.e., moisture content 50 wb at harvest) and final fuel specifications at the energy plant (moisture content 20 wb, particle size chips or chunks). Cost calculations were based on the integral cost calculation method and were presented for all process steps. The main conclusion was that the time span between harvest and energy conversion and the size and conversion technology of the energy plant largely influence tge design of the supply chain and consequently the supply costs. The fuel supply costs ranged form 17.6 to 26.1 ECU/t DM (where DM stands for oven dry matter) or 0.010 to 0.023 ECU/kWh. The cost reduction which could be achieved by choosing the minimum cost chain design could be as high as 45 or 14.4 ECU/t DM.