This report analyses the potential of Power to Gas concerning surplus renewable energy. For this purpose, the different technologies for converting electricity into the gaseous energy carriers hydrogen and methane and the subsequent storage are considered. Furthermore, various application paths are examined, and the potential of the energy carriers in the energy supply systems is assessed. After considering the possible pathways, the technology is analysed in terms of efficiency, costs, economic viability, and political aspects. These results are compared with existing projects and integrated into a cost example. Finally, the impact of PtG on the environment and emissions in terms of a renewable energy supply are analysed. It becomes clear that PtG can reduce emissions by up to 80% compared to fossil fuels. The potential of PtG for a renewable energy supply is high, but the technology still needs to improve in terms of costs and efficiency. Only when the production costs of renewable methane and hydrogen are comparable to conventional production costs, renewable energy carriers and PtG will be used on an industrial basis. A cost reduction of up to 70% is predicted by 2050, but without political intervention, PtG will not be able to compete with fossil fuels in terms of cost.