A highly integrated process for the conversion of biogenic residues in combination with electricity from renewable sources to methane-based fuels was developed. Forest residues, straw and sewage sludge were identified as particularly relevant input feedstock. By combining gasification, high-temperature electrolysis and catalytic methanation, the biogenic carbon remains almost completely in the products. The matching temperature levels of the heat streams result in a very efficient process. The production costs are comparable to less resource-saving technologies and predictably lower than those of biomethane when plant capacities are increased.