 In this study, the microwave heating conversion of carbon dioxide linked with methane and steam, a greenhouse gas, was investigated to show the possibility for chemical energy storage. In the CO2 gasification, CO2 reacts with fixed carbon in carbon receptors to produce CO, and the CO2 conversion was 81.9%. Additionally, CO2 conversion was high when the carbon receptor temperature was high and the volumetric hourly space velocity was low. In the case of dry reforming, for which CH4 was supplied with the CO2, CH4 converted to hydrogen and black carbon by thermal decomposition. The black carbon attached to the activated centers on the carbon receptor and interrupted the conversion. But CO2 conversion was 81.8%, which was not significantly different from that of the CO2 gasification. In case of the CO2–steam reforming and combined reforming which were supplied steam, however, both CO2 conversions drastically decreased to 43.9% and 36.6%, respectively, because of the reduced reactivity of the active centers caused by steam condensation in the carbon acceptor. The heating value of the product gas was the highest (14.64 MJ m−3) in the dry reforming, showing the best value as fuel. The H2/CO ratio of the CO2-steam reforming was the largest value of 1.29, enabling fuel cell applications such as solid oxide fuel cells.