In this work, a combined organic waste to biogas and power surplus management to produce green hydrogen is proposed for the Basilicata Region (Southern Italy) in order to accelerate the energy transition towards decarbonization and the integration of higher shares of variable renewable energies. The aim of this work consists of providing the techno-economic assessment of integrating current biogas production systems with Green Hydrogen production through geo-localized analysis of renewable electricity overproduction. Design and optimization of a biogas upgrade section are carried out through catalytic methanation by means of a tecno-economic analysis applied to model the whole process section. Further, a geo-localized regional case study of the integration between biogas plants and green hydrogen produced by means of water electrolysis and using a surplus of electricity from renewable resources is carried out. The main results highlighted the methane production cost without accounting for hydrogen cost is between 0.21-0.22 €/kg. However, exploiting the surplus of renewable energy production is necessary to make economically feasible the green hydrogen supply cost. For the case study considered, the potential green hydrogen availability using renewable energy overproduction is sufficient to integrate biogas plants of two municipalities producing biomethane by biogas upgrading by methanation process. © 2023 ETA-Florence Renewable Energies.