The continuing growth of renewable energy sources plays an important role in the decarbonization of the power system. However, it poses significant issues to the stability and reliability of electrical grids that require the use of flexible resources able to work on different time scales.

Electrochemical energy storage systems are the most promising tools to compensate for the uncertainty and variability of renewable energy sources, but their use is limited to several hours. To overcome this limitation, this paper proposes the use of a hybrid energy storage system based on a battery and a hydrogen storage system. In particular, the paper focuses on the mathematical picture frame to size the components that compose it.

The better set of solutions for the electrical parameters of the hybrid energy storage system’s components is obtained through particle swarm optimization. This is done by taking into account the load demand, the photovoltaic generation, the grid transaction cost and the components cost, efficiencies and lifetime.

Furthermore, the sizing procedure includes the energy management system that administrates the power flow of each component based on a filter logic. The study outcomes disclose that the use of an optimal-sized hybrid energy storage system can increase self-consumption, reducing costs and enhancing investment return.