A central photovoltaic collection array is used on a shared basis to recharge transportable fuel cell trailers each provided with an electrolysis cell. The electrolysis cell is fed by a container of water and when connected to the array the water is broken down into the constituent elements. The resulting oxygen is stored under pressure while the hydrogen is fed to a reactive bed to form metallic hydride. The heat of reaction of the metallic hydride is cooled by a heat exchanger immersed in the bed and connected between two insulated containers of water. Thus the water warmed up in the course of cooling the metallic hydride reaction is returned to an insulated chamber and in this manner serves as a source of heat for the decomposition thereof when hydrogen is desired. Once some hydrogen is released the heat of combination with oxygen may be used to continue the decomposition and as a source of power.
