CO2 Valorization as a Key Driver for the Techno-economic Feasibility of Syngas Injection into Natural Gas Grids

This study, developed within the framework of the Interreg AIHRE project (Analysis and Promotion of Renewable H2 in the POCTEP region), investigates the thermochemical gasification of residual biomass (olive and forestry residues) to produce a hydrogen-rich syngas suitable for renewable gas grid injection. The research integrates hydrogen purification and CO2 valorization into a unified techno-economic assessment to enhance both environmental sustainability and financial performance. A detailed economic model was developed to estimate capital (CAPEX) and operational (OPEX) costs, levelized cost of energy (LCOE), and financial indicators (NPV, IRR, PBP) under multiple financing scenarios. Special attention was given to CO2 valorization, considering its capture and sale for industrial applications at €1.20/kg. Results show that incorporating CO2 valorization significantly improves economic outcomes: the NPV becomes positive, the IRR increases to 10.03% (exceeding the 8.3% discount rate), and the PBP shortens to 18.55 years, well below the plant’s 25-year lifespan. These findings demonstrate that CO2 utilization can substantially enhance the techno-economic viability of biomass gasification systems while supporting EU decarbonization goals. The integration of CO2 valorization emerges as a key strategy for achieving a circular carbon economy and advancing sustainable hydrogen and syngas production for renewable gas grid applications.