Hydrogen is accepted as the energy carrier for future. Hydrogen based energy storage system represents an important option to store the fluctuating power generated from the renewable sources. A laboratory scale Totalized Hydrogen Energy Utilization System (THEUS) has been developed. THEUS consists of the Unitized Reversible Fuel Cell (URFC), which has both fuel cell and water electrolysis functions in one component, and hydrogen storage tank. THEUS was tested separately in water electrolyzer mode operation and fuel cell mode operation. THEUS was also tested continuously for three days to evaluate the energy efficiency. The URFC and hydrogen storage tank performance were characterized. In particular the overall system efficiency, stability upon cycling, and the reaction heat recovery rates of the metal hydride tank were discussed. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.