Costs, CO2-emissions and energy balance for applying Nordic methods of forest biomass utilization in British Columbia

Sammanfattning: A devastating mountain pine beetle (MPB) infestation in British Columbia has had enormous economic consequences for the lumber industry and has been one of the drivers for the development of bioenergy systems. Transportation is the link between forests and the end-users and also a critical factor for profitability. Transport efficiency can in the bioenergy context be evaluated by the costs, but also by the discharged CO2-emission levels and its energy balance. The objective of this study was to evaluate three transportation systems with the central difference in the processing level of slash. The feasibility of MPB-killed biomass was compared with vigorous biomass and all systems were modeled over a range of transport distances. Results are expressed in Canadian $/MWh, kg CO2/MWh and ratio between consumed and harvested energy (%). The Hog fuel-system, with a grinder allocated to the roadside, was generally the most economical alternative irrespective of slash amount at landing or transport distance. To produce bundles at roadside and transport to the end-user was the most economical alternative for small amount of slash (corresponding to 10 ha final felling) at landing and transport distances over 250 km. Under such conditions the combination of fairly good truckload capacity and low allocation costs compensated for the low bundler productivity. It was in all assessed comparisons least economical to transport the slash in its uncomminuted form to grind it into hog fuel after deliverance to industry. The Bundle-system and the Hog fuel-system had the lowest respectively the highest levels of discharged CO2-emissions. The systems' energy consumption corresponded to 3-10% of the harvested energy, with the Bundle-system and the Hog-fuel system being the most and least, respectively, energy efficient system. Both the Hog fuel-system and the Bundle-system are viable opportunities for the recovery of B.C.'s available biomass resources. MPB-killed biomass increased the transport efficiency as it resulted in lower costs and lower levels of discharged CO2-emissions.