Life cycle assessment of biomass chains: Wood pellet from short rotation coppice using data measured on a real plant

This paper presents a LCA study about household heat from Short Rotation Coppice wood pellets combustion. The overall process, from field growth to ash disposal, was considered; environmental analysis was carried out using a LCA software programme (Simapro 7.0) and adopting the EcoIndicator 99 model for the evaluation of the global burden; analysis with EPS 2000 and EDIP methodologies were also carried out, in order to compare the different approaches. For the pellet production process, mass and energy flows were measured on an existing Italian plant, while other data were obtained from the Literature; a comparison between results obtained using only data from Literature and using data from the existing plant was made, showing for the pelleting phase a value of about 23% lower if measured data are used. The LCA study showed that agricultural operations account for most of the environmental impact if evaluated both with EcoIndicator 99 and EPS 2000; EDIP gave results that were not very reliable for this chain, due to the high weight given to the infrastructures and machinery construction. The comparison between data obtained considering and not considering the infra-structures contribution in the LCA analysis with EcoIndicator 99 showed a modest contribution of infra-structures on the final score (about 2%). The overall impact evaluated with EcoIndicator 99 is considerably less than the one caused by natural gas heating. The Energy Return Ratio was finally calculated; a value of 3.25 was found, good if compared to the one for the methane combustion, equal to 6. (C) 2010 Elsevier Ltd. All rights reserved.