Electrolysis is based on the water splitting into H2 and O2, the energy for this reaction is given in the form of electricity derived from Renewable Energy Source (RES) i.e. photovoltaic panels (PV), wind farms hydropower and geothermal plants. Since the H2/CO2 ratio for CO2 hydrogenation towards hydrocarbons synthesis should be four (4) for methane and three (3) for methanol synthesis, the required amounts of hydrogen are very large