Comparative analyses of forest fuels in a life cycle perspective with a focus on transport systems

Local, national and international transportation of forest fuels with regard to costs, primary energy use and CO2 emission was analysed. The main issue was the extent to which both mode and distance of transport affect the monetary cost, CO2 emission and primary energy use arising from the use of various types of forest residues for energy purpose. Local applications proved the most efficient options of those studied. Chipping of bundles at a terminal, for transport by rail and sea to national or international end-users, has low costs and produces only modest CO2 emissions. For the pellet options, the cost is about the same as for chipping, but require more primary energy and emit more CO2. The traditional chipping system is more expensive than the other options. The costs of the international options over a transport distance of 1100 km vary between 21 and 28 €2007/MWh, whereas pellet options cost between 22 and 25 €2007/MWh. The primary energy required for transport of logging residues vis-à-vis pellets falls in the range 4–7% and 2–4%, respectively, of the bio-energy delivered. The primary energy needed to produce pellets gives them a lower fossil fuel substitution rate per hectare, compared with bundle systems. Similarly, for chip systems vis-à-vis bundle systems, the biomass delivered to the conversion plant is reduced by the greater physical dry-matter losses entailed by chipping systems in the forest-fuel chain.