NOVELTY - System (100) comprises: a reactor (102) having a first chamber (104) comprising passage between inlet and outlet containing at least a porous electrically conductive cathode (108) and culture of living methanogenic microorganisms and water and a second chamber (106) comprising at least an anode, separated by proton permeable barrier; a source of electricity coupled to anode and cathode; and a supply of carbon dioxide coupled to first chamber, where outlet receives methane from first chamber. The reactor has operating state and culture maintained at 50 degrees C.    USE - The system is useful for converting electric power into methane (claimed), which is useful: to replace natural gas in local operations for heat; in chemical production; and in industrial, commercial, transportation or residential needs (e.g. conversion into electricity through combustion in a carbon-based fuel generator or other uses e.g. heating or cooking, non-combustion based conversion of methane into electricity e.g. via fuel cells, or chemical conversion into other compounds e.g. via halogenation, or reaction with other reactive species).    ADVANTAGE - The system: provides a non-fossil carbon-based energy resource, thus reducing the reliance on fossil-based carbon fuels; converts or processes carbon dioxide to generate energy resource by removing carbon dioxide from the environment, thus preventing carbon dioxide from being released into the atmosphere or into a storage system or into another process; provides methane which can be transmitted via natural gas transmission pipes which on a per unit energy basis are less expensive than electrical transmission lines; provides simplified handling of the methane post-processing or generation; and provides methane in a liquid form, which is more convenient for storage or transport.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of the reactor for converting electric power into methane.    System (100)    Reactor (102)    First chamber (104)    Second chamber (106)    Cathode (108)