Disclosed is an improvement in the process of conveying heat energy by means of the exothermic and endothermic reactions involved in the conversion and re-forming of methane. According to the invention, methane is steam-reformed in an endothermic reaction, utilizing heat energy, to a gas comprising hydrogen, carbon monoxide, carbon dioxide and water vapor. The gas is substantially freed of water and is conveyed to a location wherein heat energy is desired. The heat energy is released upon re-forming methane and the exothermic reaction wherein methane is re-formed is carried out at elevated pressure and at least in part at temperatures between about 400.degree. and 650.degree. C. The methane so produced can be recycled if desired.