The production of a synthetic methane from hydrogen and carbon dioxide using renewable electricity enables long-term energy storage, provides clean fuels for electricity generation and thermal energy and can help power systems transition to climate changes mitigation and large-scale renewable energy deployment. This paper evaluates the economic performance of synthetic methane production, which is especially prospective in the Baltic region, because allow utilize the existing gas infrastructure, that includes a gas pipeline transmission and distribution network, gas power plants and a large underground reservoir. We use power systems optimization model, which include sub-models of renewables power sources and interconnections with Scandinavia and Poland considering NORDPOOL electricity market rules. The assessment of gas amount and costs, required capacity of plant for energy balancing, scale of necessary investments constitutes the main outcomes of this paper. Conclusions are on the interests of high-level energy transition planners and decision makers.