The sulfur tolerance of mono- and bimetallic ruthenium catalysts for CO2 hydrogenation was investigated in microchannel reactors. H2S was selected as a model compound. It was found that a Ru/CeO2 catalyst deactivates rapidly. Ni was a much better additive to improve the catalyst stability compared to Rh and serves as a sulfur trap. The influence of the support was evaluated showing that a SiO2-supported catalyst has a higher stability and better selectivity compared to CeO2 and TiO2. A plant concept was developed comprising two-step methanation with a first adiabatic reactor stage followed by a plate heat-exchanger reactor with integrated cooling which allows more than 97 % CO2 conversion. A pilot plant will be put into operation in connection with a biogas plant and an electrolyser of 50 kW power consumption.