Calculation of on-farm biogas potential: A Croatian case study.

Energy planning relies on potential assessments where the role of each energy source in the energy balance will correspond to the attributed potential. Biogas is a gaseous renewable energy fuel derived from biomass. It origins from numerous substrates and provides all useful energy forms which makes biogas potential assessment challenging. Biogas production and utilization has also side-effects from which a country could both benefit, and, if not properly addressed, suffer. Practice proves that a demand based approach to agricultural biogas potential assessment is not providing the value(s) to which either energy or rural development policy planning can work with. The problem stems from three main challenges: (a) biogas rarely occurs in monodigestion, (b) co-digestion has to compete with other non-food sectors for co-substrates, (c) biogas production needs constant inputs. Paper provides methodology to assess the technical and economical on-farm biogas potential of a geographic region. Technical potential assessment links resource based, statistical data with spatial data of single farms to detect farms with plausible biogas production. Return on investment is used to trim the technical to economic potential. Results provide sufficient data for developing on-farm biogas production and its conversion to useful energy forms in energy planning. The methodology is applied to Croatia as a case study. The results indicate discrepancy between the existing biogas supporting measures and features of the Croatian livestock sector. In addition, the results suggest that biogas potential is underestimated which is potentially loss in public money dedicated for development of renewable energy sector. [ABSTRACT FROM AUTHOR]