The rapidly growing share of renewable energy in the energy mix calls for a development of the appropriate energy storage technologies. To store the surplus of the energy produced from the available volatile sources over longer periods of time, such that it is available when a need arises, the storage technology needs to have the sufficient capacity. The innovative Power-to-Gas system solution offers the possibility to store this green electricity surplus in the form of synthetic natural gas (renewable methane gas), and make it available for the time periods when the need for the electricity is higher. The economic and the technical perspectives of the new technologies are explained in the context of the work. The effects of the parameters influencing the methane costs are graphically presented and evaluated under different scenarios. The technical development- and optimization measures are identified, and the tasks to improve, i.e. to decrease the economic costs are elicited.