Greenhouse Gas Emissions, Energy Use, and Costs–Case Studies of Wood Fuel Supply Chains in Scandinavia
AbstractUse of bioenergy based on woody biomass has become increasingly important in recent years, especially in European countries. In three case studies from Scandinavia, we conducted life cycle assessment (LCA) of alternative wood fuel supply chains (WFSCs) with respect to greenhouse gas (GHG) emissions, energy use, and costs. Case study 1 is a local Norwegian supply chain, while case studies 2 and 3 are international WFSCs, where woody biomass is exported to Sweden from respectively lowland and mountain forests in Norway. The GHG emissions and energy use in the case of wood chip exportation from Norway to Sweden were lower than in the local alternative use of the biomass. The emissions were 31.7 kg CO2e/m3 solid over bark (67.4 kg CO2e/MWh) for case study 1; 22.2 kg CO2e/m3 solid over bark (47.2 kg CO2e/MWh) for case study 2; and 23.9 kg CO2e/m3 solid over bark (50.8 kg CO2e/MWh) for case study 3. From a GHG point of view, WFSCs with relatively long transport distances were best when transportation was by railway and the combustion plant had high efficiency. The highest GHG emissions occurred in the truck transportation and chipping operations. Energy input-output ratios show that for case studies 1, 2, and 3, respectively, the fossil fuel energy inputs were 4.5%, 3.4%, and 4% of the bioenergy produced. Forest fuels from mountain forests in Norway seem promising for filling the high demand for wood fuel in Sweden, where bioenergy use is relatively high. In all case studies, the GHG balance was positive, especially when wood fuel plants substituted energy production from coal and oil plants. The cost analysis showed that wood chip import from Norway to Sweden was economically feasible. Keywords: bioenergy, LCA, mountain forests, Norway, supply chains, Sweden. Received 6 January 2012, Revised 3 February 2012, Accepted 8 February 2012.