Improving the financial performance of solid forest fuel supply using a simple moisture and dry matter loss simulation and optimization

We constructed a computation scheme that combines GIS, simulation and optimization techniques for assessing the moisture change, dry matter loss, transportation costs and net present value of solid forest fuel piles. This scheme was applied to predict the value of a stock composed of multiple piles, and to find the optimal feedstock allocation strategy, i.e. the selection of piles and the combustion time so that the total energy yield or the economic value of the energy production is maximized. According to the simulation, single Norway spruce energy wood piles reached their maximum energy content during July-August in boreal conditions in Finland. If a pile was created between January-September, the maximum energy content occurred in the same year, whereas for piles created between October-December, the maximum occurs in the summer of the following year. In the optimized combustion sequence, the piles generated in early Year 1 were combusted first. The main outcome of the study was that the simulation-optimization scheme can increase the gained net present value of the feedstock by 2.0%-6.4%, and the benefit increases with increasing heterogeneity of the feedstock. Forest fuel supplier can get considerable savings by applying the presented system to decide the combustion sequence of the existing feedstock. From practical point of view this is remarkable because the savings can be achieved without any investments only by arranging the transportation sequence. The presented computation system uses easily available input, can be modified to different condition, and can be run with standard IT-resources.