Life Cycle Assessment of Wood Chips from Residual Biomass: A Case Study

Abstract

The paper describes the results of a Life Cycle Assessment study of wood chips obtained from a residual forest biomass, to be used for energy purpose. The analysis is referred to 1 kg of wood chips as functional unit. The system boundaries include the collection of the residual biomass, the chipping process of biomass, the collection and transport of wood chips to the energy plant. The results show that the supply chain examined, with reference to the functional unit, causes an impact of 0.027 kg CO2eq and a consumption of 0.406 MJ of primary energy. A dominance analysis was developed to identify the most impactful stages of the production chain: the steps that contribute most to the impacts within the supply chain are the indirect drag and the chipping process, responsible for the 42% of the overall greenhouse gas emissions and primary energy consumption. Lastly, a sensitivity analysis was carried out, to assess the variation of the impacts related to the distance between the wood chips production site and the place of use. The sensitivity analysis shows that is important to have short supply chains within the proposed domain in order to lower the energy and environmental impacts.