Heating from Biogas Plants: An Areal Approach for Enhanced Environmental Sustainability

The availability of renewable energy sources and highly efficient technologies are two critical aspects in evaluating a sustainable low-carbon energy supply. The efficiency of power generation in anaerobic digestion plants is around 35%. The remaining portion of the energy is heat produced in biogas combustion. This heat is usually used to supply the plant itself and the production facilities where it is embedded. However, this supply is only a fraction of the heat produced, lost mainly as waste. To recover the excess heat produced in biogas plants, this research aims to quantify the thermal needs of the buildings around the anaerobic digestion plants in one province of the Veneto Region (Italy) that can be supplied by the plants through district heating systems. District heating systems are an experienced and reliable technology that can validly be used to exploit the economies of scale of centralized heat production. The analysis found that the plants can provide up to 775 MWh/d of heat, saving 25.5–106 m3 of CH4, and reducing emissions by 127 t of CO2 each day.