Simple CO2 capture in combined solid oxide fuel cell (SOFC) gasification or reforming (of hydrocarbons fossil or biomass) cycles by condensing the water vapor of the anode exhaust gas after CO shifting and H2 recycling by a membrane is simulated. High efficiency of about 60?% is demonstrated. The separated CO2 can be stored in a two-chamber tank at the same pressure and temperature as methane on the two sides of a flexible membrane which divides the tank into chambers since 1?mol CH4 results in 1?mol CO2. In a solid oxide electrolyzer cell (SOEC), CO2 and steam can be recombined to CH4 using excess electricity, e.g., produced by wind or solar power, and O2 is left over. Thus, excess electricity can be stored chemically. Such a cycle allows hybrid vehicles with SOFC as range extender, running as zero-emission vehicles also when using natural gas.