Energetic and Environmental Balance of a Biogas Plant in Northern Italy

For the achievement of the European Union (EU) goals, the Anaerobic Digestion (AD) of energy crops and agricultural wastes – with more than 520 running plants in Italy (350 electric MW installed) – appears as one of the most promising agro-energy chain for agriculture of Northern Italy. In this work, the energetic and environmental assessment of an agricultural biogas plant is analysed according to the guidelines reported in RED Directive and in COM(2010)11. The AD chain has been divided into 3 phases: biomass production, transport and storage, and energy conversion. Results appear very good both from energetic (Energy Returned On Energy Invested – EROEI ≅ 2) and environmental point of view. In fact, AD allows a considerable Greenhouse Gas (GHG) emission saving in comparison to the Italian Electricity system as well as to the reference system reported in the COM(2010)11.