Analysis of Different Configurations of Hybrid Fuel Cells System With Supercapacitors and Battery for Small Stationary Applications

The overall characteristics of electric power grid in terms of continuity of the supply and energy quality are of outmost importance for both industrial and civil applications with special attention to the uninterruptible ones. Net congestion problems are becoming more and more frequent boosting the development of small energy generation systems with back-up function. In this field low temperature fuel cells are an interesting solution addressing both environmental and efficiency issues. In the present work the application of Polymer Electrolyte Fuel Cells (PEFC) for an Uninterruptible Power Supply (UPS) system (<1kW_e) is analysed by examining different possible technical solutions. This system is composed by a PEFC 1kW_e stack, assisted by a set of battery and a supercapacitors pack, and using hydrogen stored into a metal hydride tank. Critical aspects as system start-up, response rapidity and autonomy are addressed to obtain an optimal configuration. Both numerical and experimental analysis have been carried out to characterize component behaviour. Once realized and tested, the system has proved to be able to work as UPS with an autonomy of 6.5 hours, only determined by hydrogen storage capability.