Techno-economic assessment of a hydrogen-based energy storage system for an energy community

In the context of the current energy landscape, the need to harness renewable resources (RES) has become an imperative. In this scenario the use of hydrogen as energy storage vector, linked to the increase of renewable power generation, can play an important role to overcome the flexibility issues associated to the variability of RES. This work entails a feasibility study and proposes the operation of a hydrogen-based storage system to be integrated with a PV power generation placed in an energy community in Barcelona. The project is performed gathering real time data obtained in the framework of a collaboration between an industrial energy community in Barcelona, the Barcelona Metropolitan Area (AMB) and the Universitat Politècnica de Catalunya (UPC). In this work different control and operation proposals are analyzed and compared, checking in each case the prospective benefits that could be obtained from the combination of a hydrogen-based energy storage system and photovoltaic system. The primary objective of the study is to identify the most economically profitable operating strategy, considering the electricity market price and the requirement to fully meet the load demand, while keeping a constant level of hydrogen within the storage on a daily basis. The initial part of this work includes the modelling of the main components needed to build a power-to-power system, which are electrolyzer, hydrogen storage tank and fuel cell. These models provide the electrochemical behavior and the main dynamics of the components. The models are developed in Matlab/Simulink® and use continuous time solvers. Finally, the RES generation and the load profile is taken from real measurement obtained in the environment of an industrial community. To determine the optimal control strategy for the energy system from the economic point of view, a step-by-step approach has been developed, gradually introducing additional energy paths, to create a more comprehensive and detailed setting. An analysis through weekly simulations with 1-hour time step permitted to determine the most cost-effective configuration. The lowest overall net cost was obtained, and the same methodology was applied for another size of the photovoltaic system to find the optimal. One remarkable finding is that the strategy based on no selling the excess energy generally leads to lower overall costs. In fact, the selling strategy requires a higher amount of energy to be purchased from the grid, resulting in larger sizes of the electrolyzer and the fuel cell. However, the increased cost associated with these larger components is not sufficiently offset by the revenues generated from the selling of electricity.