Battery and hydrogen-based systems to store electric energy from renewable sources: Performance and comparisons

In this paper hybrid power plant configurations based on a photovoltaic power system integrated with an energy storage unit are proposed and analyzed. As storage technologies a hydrogen based system, that consists of an alkaline electrolyser (AEL) and a polymer electrolyte membrane fuel cell (PEMFC), and Li-ion battery system have been chosen. The hybrid power plant in both configurations has been designed and sized with the aim of satisfying the energy demand of a radio base station located in a remote area. In this study a sensitivity analysis based on the PV power system size has been performed; thus, once assigned the PV unit size, the other plant components (the PEM FC, the electrolyzer, the battery unit and reciprocating engine) have been defined and characterized. The performances of the proposed plant configurations have been compared in order to evaluate, as each power system is able to satisfy the energy requirements during the year. Results showed that the hybrid power system is able to operate by using only the renewable resource (solar energy) if: a) the PV power system of 17 kWp integrated with the hydrogen storage unit is installed; b) the PV power system of 15 kWp integrated with the battery system is installed;