Grid-independent PV system hybridization with fuel cell-battery/supercapacitor: Optimum sizing and comparative techno-economic analysis

In this paper, a comparative techno-economic assessment of two different hybrid energy storage system configurations viz. fuel cell-battery energy storage system (FC-BESS) and fuel cell-supercapacitor energy storage system (FC-SCESS), incorporated in a grid-independent photovoltaic (PV) based power system for a residential building is performed. Firstly, load for the residential building is calculated and accordingly optimum sizing of various constituents of the PV system is obtained using HOMER. Subsequently, the economic analysis for both configurations is performed in terms of cost of energy, net present cost, initial cost, and operating and maintenance cost. The simulation results of HOMER suggest that for grid-independent PV based power system, FC-SCESS configuration is better from the economic point of view. As HOMER's inability to perform detailed technical analysis, MATLAB/Simulink models of both configurations are built and comparative analysis is performed in terms of different technical aspects such as active power balance, DC link voltage (VDC) regulation etc. From MATLAB results, it is observed that FC-SCESS configuration performs better by regulating the VDC more effectively and thereby helps maintain the active power balance between various constituents of the power system. Furthermore, feasibility of hardware implementation of each configuration is verified using hardware-in-loop real-time digital simulator.