Renewable energies have been introduced widely in Japan, so that necessity of electricity storage system has been increasing for load leveling and demand regulation Hydrogen electricity storage system is suitable for large capacity and long time storage This paper reports that hydrogen electricity system using SOEC (Solid Oxide Electrolysis Cell) and SOFC (Solid Oxide Fuel Cell) achieves high charge-discharge efficiency And this paper shows the system diagram which contains sell-stack, high-temperature thermal storage, low-temperature thermal storage, and heat-exchangers Furthermore this paper reports high temperature thermal storage test using NaCl as thermal storage material
