Fuel consumption and GHG emissions of forest biomass supply chains in Northern Sweden: a comparison analysis between integrated and conventional supply chains

Forest biomass can be used as source of renewable energy, contributing to mitigate climate change. Currently, forest biomass is one of the most important energy sources in Sweden, accounting for around 20% of the total supply. New demands of forest biomass may be expected due to the European Union energy targets, the previous high oil prices, the energy supply security, and the bioenergy market. However, the supply depends on the intensity of conventional final felling operations. Thus, it is crucial to determine the energy demands of conventional and new forest assortment supply chains and promote those with the highest energy efficiency and least greenhouse gas (GHG) emissions. An attributional life cycle assessment approach was used to evaluate the fuel consumption and GHG emissions associated with the combustion of fossil fuels used in forest operations, transportation and comminution of forest biomass procured via two kinds of supply chains in Northern Sweden: conventional and integrated. The results indicate that most fuel was consumed in transportation processes. The integrated supply chains (in which the harvesting of industrial roundwood is integrated with extraction of forest fuels) are more energy efficient than conventional supply chains, and have the potential to reduce GHG emissions by approximately 13%.Abbreviation: BWT: bundled whole small trees; CTL: Cut-to-length; ET: energy thinning; FF: final felling; FT: first thinning; FU: functional unit; GHG: greenhouse gas; GWP: global warming potential; LCA: life cycle assessment; LR: logging residues; LT: long tops; ODt: oven dry tonne; ORN: ornskoldsvik (industrial location); PCT: pre-commercial thinning; PL: pulpwood; PM(15)h: Productive machine hours including delays shorter than 15min; RS: Rough-delimbed tree sections; SC: stump core; SL: sawlogs; SP: stumps; ST: second thinning; STO: Storuman (industrial location); u.b: under bark; UME: Umea (industrial location)