Based on these relevant examples, this work developed detailed models of the CO2-to-SNG and CO2-to-methanol reactions. These models were used to perform a techno-economic assessment of the energy carrier production from renewable energy in a decentralised way. As the CO2 source, biogas was considered, taking advantage of the low-cost CO2 that can be recovered through power-to-X coupling with biogas upgrading (biomethane production) .