Photovoltaic-driven electrolysis and lignocellulosic biomass gasification to enhance renewable fuel production in Italian biogas plants

Decarbonizing the energy sector will require combining renewable energy resources and integrating fuel production technologies. This study evaluates photovoltaic-driven electrolysis and biomass gasification with the goal of increasing biogas plants fuel output. The potential of fuel production pathways was assessed through the analysis of their nationwide impact on the Italian biogas sector. Additionally, the composition of produced fuels was evaluated for future sector coupling studies. A spatial analysis was performed to assess the availability of free surface for photovoltaic installations within the 2010 existing biogas plants and the regional distribution of biomass resources in Italy. Results indicate that up to 893 MWe of PV capacity could be installed, with a potential production of 19.6 kt/y of green hydrogen as subsequent valorisation. Integrating biomass gasification and syngas blending with biogas was identified as another viable approach to valorise lignocellulosic biomass. The analysis shows that gasification could potentially increase by up to 100 % and 52 % the energy output of biogas plants below 500 kW and above 2 MW, respectively. Despite lower energy resource availability, northern Italy plants show the highest additional energy production potential, peaking at 1.29 kt/y of green hydrogen in the province of Torino. The methodology and results reported in the study provide a data-informed framework for the optimization of biogas plant operations and the maximization of renewable energy production, thus supporting transition towards sustainable and low-carbon energy production systems.