Open access publications in the SLU publication database

Abstract

Forest biomass has gained much interest as a resource for renewable energy production world-wide. In Sweden, easily accessible secondary forest fuels, such as by-products from the conventional forest industry, are today already fully utilised. There is still potential for expansion by greater utilisation of primary forest fuels, which consist of biomass previously left in the forest after logging, e.g. tree stumps and logging residues. However, to increase the volumes of these fuels, more cost-efficient supply systems must be developed to overcome strong price competition from other fuels. Since forest fuels are low-value goods, the profit margins are tight, resulting in low acceptance for inefficiency. Storage, comminution and transport are all required to deliver a product with acceptable quality when needed by the end-user. However, there are many ways to organise the supply chain, including use of different machines, strategies and forms of work organisation, which together result in numerous possible systems.

This thesis assessed the efficiency in forest fuel supply chains and sought to provide decision support on how, where and when biomass should be managed and handled to deliver a high-value fuel with low input of resources. Finding more efficient ways to organise the supply chain can lead to increased amounts of primary forest fuels being brought to market at a profit. For this, good decision support on which system to use in different situations and the consequences of different choices is needed. The methodology used in this thesis was discrete-event simulation and models of different supply chain alternatives were developed.

The results indicated that there is no such thing as a perfect system, but that each system can have its own niche. A hot system with a high degree of machine dependency must have a proper balance in machine capacity to be efficient. For transport and comminution, ensuring high utilisation of the comminution unit is key to increased cost-efficiency. There is a strong link between quality parameters and supply chain activities, which ideally should be planned with respect to present quality. It is possible to tailor fuel deliveries concerning quality by delivering the right biomass at the right time.