LCA of bioenergy chains in Piedmont (Italy): A case study to support public decision makers towards sustainability

Given the booming of bioenergy plants under construction in Piedmont, in Northern Italy, Life Cycle Assessment (LCA) was used in order to assist public decision-makers during the evaluation of new bioenergy projects. Local administrators are in fact worried that public incentives granted to bioenergy producers, regardless of the overall environmental performance, might not encourage technological innovation and eco-efficiency, or bring unwanted indirect environmental effects. A detailed LCA of bioenergy production from dedicated crops (maize, sorghum, triticale and miscanthus) and manure through anaerobic digestion and combined heat and power generation was carried out. The LCA model was particularly focused on the end-of-life of digestate and site-specific data related to the impact of adopted energy conversion technologies. It was confirmed that bioenergy is not automatically synonymous with sustainable energy, as the differences in terms of environmental performance can be remarkable. EROI (Energy Return on Investment) index was estimated to be 3–5. The potential in terms of GHG saving depends on several factors and it is heavily influenced by the reference non-renewable energy to be substituted. End-of-life of digestate was found to be crucial for acidification and eutrophication, but also for GHG emissions. Finally, particulates equivalent emissions were found to be very large in comparison to modern natural gas power plants.

► A detailed LCA of bioenergy production in Northern Italy was carried out.
► The LCA model was particularly focused on the end-of-life of digestate.
► It was confirmed that bioenergy is not automatically synonymous with sustainable energy.
► The potential in terms of GHG saving largely depends on several factors.
► Particulates equivalent emissions can be up to 5 times larger than natural gas.