Cost analysis of chaff harvesting concepts in Germany

This work assesses the costs of exploiting the biomass feedstock chaff. Chaff is a harvest residue generated during the conventional grain harvesting process and usually remains on the field. In this paper, the costs of collecting and supplying chaff to the end user with different harvesting methods and supply chains are analyzed. The costs are estimated for a base case defining a set of general assumptions. The impact of these assumptions is analyzed in a sensitivity analysis by means of tornado diagrams. A full costing method based on the VDI guideline 2067 part 1 is applied for the cost estimation. The cost analysis reveals that ceasing the fractioning of grain, straw and chaff during harvesting and transporting them as a mixture reduces the harvesting costs significantly. The costs are decreased due to a reduction in agricultural operations and processing large amounts of material. The lowest total costs originate from the production of chaff-straw bales. Harvesting chaff as a single fraction leads to the highest costs with the investigated supply chains. Comparing the costs of chaff supply to potential revenues shows that an exploitation of the harvest residue can be economically feasible.