A small-scale seasonal energy storage system, comprising an electrolyser, metal hydride hydrogen store and fuel cell, has been studied. According to the feasibility study, solid polymer electrolysers and fuel cells are the best options for the electrolyser-metal hydride-fuel cell energy storage systems. A round-trip efficiency of 30% has already been demonstrated, and the next target is to reach a round-trip efficiency close to 40%. The electrolyser-metal hydride-fuel cell systems are suitable for small-scale self-sufficient applications in which high volumetric capacity is needed and safety aspects are appreciated. (C) 1997 International Association for Hydrogen Energy.