Potential Analysis of Agro-Municipal Residues as a Source of Renewable Energy

Abstract

Declining grassland management in the Austrian Alps demands alternative usage strategies for unused biomass. This case study suggests biogas production as a suitable solution. The study employs a novel calculation scheme to calculate the biogas potentials of grassland and agro-municipal wastes in two model regions. In economic terms, model region one relies heavily on winter and summer tourism with few agricultural operations. Model region two has less intensive tourism and a more prevalent agricultural sector. Using a linear regression model, changes in animal stocks, biogas yields, and energy production were calculated for 2010, 2020, and 2030. Results showed that in 2010, model region one had 1186 t dry matter (DM) a⁻¹ unused grassland biomass, which, combined with other agro-municipal wastes, could have produced 524,580 Nm³ a⁻¹ of methane. Combusting this amount of methane in a CHP would result in 2 GWh_el a⁻¹ and 2.2 GWh_th a⁻¹. Similarly, including wastes and 557 t DM a⁻¹ unused grassland biomass, model region two could have produced 1,305,892 Nm³ a⁻¹ methane and 4.9 GWh_el a⁻¹ and 5.5 GWh_th a⁻¹. By 2030, unused grassland biomass is predicted to increase in both regions. Including other organic and agricultural residues, the total methane potential for region one will be 575,784 Nm³ a⁻¹ (+9 %) and 1,769,471 Nm³ a⁻¹ (+36 %) in region two by 2030.