In 2014, the first commercial 6-MW P2G plant commenced operation in Werlte, Emsland. The car manufacturer Audi uses renewable energy to produce H2 and CO2 from the existing biogas plant in order to generate the so-called e-gas for the CO2-neutral mobility of their customers, who have CNG vehicles. The plant features a complex thermal management system that makes it possible to supply the various heat consumers in the biogas plant with the waste heat recovered from electrolysis and methanisation. CO2 is separated from biogas by treating it with amine gas, whereas the regeneration of the CO2-laden amine solution is a thermal process. Thermal management represents a major challenge because unlike the biogas plant, the P2G plant is not operated on a stationary basis but on the basis of the current energy supply situation. The WOMBAT simulation, devised as part of the joint project funded by the German Federal Ministry for Economic Affairs and Energy (BMWi), simulates the monitoring system including the collection, storage and evaluation of data, and provides the necessary tools to assess and optimise the plant operation.