The chemical methanation of CO2 is an optional step of the Power to Gas concept (PtG). In the first process step of the PtG technology, water is decomposed into hydrogen and oxygen using an electrolyzer. The electrical power (Power) used for this purpose - minus losses - is stored in the gaseous compounds (Gas). This makes it possible to replace conventional energy sources with fluctuating renewable energy as envisaged by the European energy policy in context of the “Energiewende”. In order to utilize the currently available energy infrastructure for storage, distribution and utilization, a conversion of hydrogen to methane, also called Substitute Natural Gas (SNG), is necessary. The use of CO2 as a carbon carrier can additionally reduce the emission of greenhouse gases into the atmosphere and thus counteract climate change. The methanation of CO2 with H2 is an exothermic heterogeneously catalyzed gas phase reaction. The metals of the iron-platinum-group are catalytically active substances. Nickel is usually used because it is comparatively inexpensive at high activity and selectivity. In addition to the active substance, the geometry, the carrier substance and the porous coating (washcoat) of the catalyst are responsible for the CO2 conversion behavior. In this work, two differently long honeycombs and a bed of a spherical shaped commercial catalyst are compared with respect to CO2 methanation. The coating consists of a y-Al2O3 washcoat and nickel. The experiments are carried out in a three stage plant (laboratory scale) with variation of space velocitiy, H2 /CO2 ratio and pressure. Methane and carbon monoxide concentration as well as conversion, equilibrium conversion and selectivity are determined in the product gas. The influence of the catalyst geometry, in particular the length of the honeycomb catalyst, is concluded by comparing the measured and calculated results of the experiment.