Analysis of factors affecting productivity and costs for a high-performance chip supply system

Declining market prices make it necessary to reduce supply costs of forest chips to ensure profitability in the supply chain and a continued supply of forest chips to the energy industry. Comminution and transport are two of the major contributors to the total costs in the forest fuel supply system. In order to fully utilise truck payloads and reduce transport costs, logging residues are usually chipped at the landing. For the chipping contractor, it is important to maximise the proportion of effective work time in relation to scheduled work time. Currently it is not uncommon that effective work time is less than 50 per cent of scheduled work time, due to chip transports using the chipper, waiting for chip trucks, and other delays. Increased chipper utilisation requires greater coordination between the chipper and the chip trucks transporting the produced chips to the customer. Supply systems have been simulated to examine how transport distance, number of trucks, shift scheduling and chip buffers affect the system costs for a high-performance chipper system. System costs and machine utilisation vary greatly, depending on system configuration. It is always beneficial to have six containers in the buffer on the landing rather than three, and trucks should begin their shifts at one-hour intervals. To maximise chipper use and minimise system costs, four container trucks are needed if the transport distance exceeds 50km. However, the large seasonal fluctuations in demand for biomass chips makes it hard to fully utilise the potential of the system over the whole year. The study concludes that it is important to regard chipping and chip transport as one operation, not two separate ones, as they are so dependent on each other.