Economic feasibility and environmental benefits of farm-scale biogas plants

The agricultural biomasses constitute a prominent part of the renewable energy that have a key role in the energy policy of European Union. In the last years the electricity production from biogas generated by anaerobic digestion of biomasses has been considerably supported at national level. In this study a financial analysis of farm-scale anaerobic digestion plants has been carried out to evaluate the profitability of the projects from a private point of view, and an economic analysis have been carried out to underline the projects‟ social and environmental benefits that affect the community on the whole. The results of the financial analysis show the determinant and necessary role of the incentive to guarantee the financial profitability of the projects. Whereas the economic analysis highlights a lack of data in the literature about the appraisal and monetization of the potential externalities generated by the farm-scale biogas chain; moreover it proves that the feed in tariff applied is overestimated respect the tariff that make the projects economically feasible. The anaerobic digestion plants fed only with animal manure and sewage present higher externalities than the once fed exclusively with energy crops. However the adopted feed in tariff support both the plant typologies without distinction, but for the plants that use only energy the financing is not justified because the non-equivalents social and environmental benefits.