With the increased integration of renewable energies in distribution networks comes the need for energy storage systems. Due to its characteristics, the use of hydrogen as an energy vector shows propitious features with this purpose. This study presents a type of storage energy system composed of an electrolyzer, hydrogen accumulator and fuel cells. To model this system, it is necessary to establish a set of physicochemical equations for each component in order to integrate a large number of parameters and variables dependent on the model and operating conditions. This study describes a model for real storage power plants consisting of an alkaline electrolyzer, a PEM fuel cell and a hydrogen accumulator in metal hydrides. A description of some practical tests on each component of the plant is included in order to compare them with the simulated results. All steps and parameters are discussed with the purpose of being used for other plants of similar characteristics. (C) 2016 Elsevier Ltd. All rights reserved.