Optimal sizing of hybrid fuel cell-supercapacitor storage system for off-grid renewable applications

Highlights: • The Net Present Cost for the optimal configuration is $26.6 million. • The corresponding levelized cost of energy is US $4.78 per kWh. • The cost of storing hydrogen influences substantially the levelized cost of energy. • The proposed energy system is less cost effective for a commercial load. -- Abstract: The deployment of off-grid renewable systems using variable energy sources like solar and wind as an alternative to the grid extension in remote areas with no access to electricity is becoming widespread. However, due to the fluctuating nature of power outputs from these generators and that of the loads, an off-grid renewable power system should include an energy storage facility. Various energy storage technologies exist in the market, yet, each of them considered individually has not proven to be technically and economically viable. Integrating two or more energy storage devices as a single entity increases the reliability and security of supply in an off-grid renewable power system. In this study, a hybrid energy storage combining a hydrogen fuel cell and a supercapacitor is simulated, the objective is to find the optimal size of a composite energy storage system for a commercial load supplied from photovoltaic panels. The suitable architecture is adopted based on its technical feasibility and cost effectiveness. Sensitivity analysis on the projected costs of hydrogen storage is carried out to evaluate the impact of the hydrogen cost on the cost of the system and the levelized cost of energy. The simulation is performed under Cape Town weather conditions using HOMER Pro.