Eco-efficiency assessment of farm-scaled biogas plants.

The aim of this study was to analyse the eco-efficiency of 15 agricultural biogas plants located in Northern Italy. For this, the combination of life cycle assessment (LCA) and data envelopment analysis (DEA) methodologies was considered with the purpose of identifying efficient operational plants and proposing improvement measures for the inefficient ones. The environmental profile of both the original and the virtual plants (obtained after the improvement measures) were compared in order to identify the net environmental gains linked with the inputs reduction. As a result of improvement measures, the production of electricity from biogas in all plants would imply environmental benefits compared with the average electricity production in the Italian grid. In light of the results obtained, special attention should be paid to the feedstock selection since it has a key role in the overall eco-efficiency of the plant, due to their different origin and composition.