Abstract This work presents a profitability analysis of a novel route to produce biomethane and synthetic natural gas through Power-to-Gas technology. Differently to traditional Power-to-Gas processes, the process configuration herein proposed allows to produce biomethane even if a source of hydrogen is not available. The novelties of this work are both the new process configuration and the comparison among results for several plant sizes (100, 250, 500, and 1000 m3/h) under two representative EU scenarios (Spain and Germany). The main finding of this work is that no profitable results can be obtained at the present natural gas prices, evidencing the need of incentives. Largest plant could reach profitability under reasonable subsidies (12–15 €/MWh). The forecasted cost reduction for H2 production and CO2 methanation are also analysed. The results show that subsidies are needed even in the most optimistic scenario. A corollary of this study is the current technological great challenge to develop low carbon routes which push forward the transition towards sustainable societies.