Based on the results, the Net Present Cost (NPC) of the solar and wind-powered hydrogen storage system was $449523 and the year-round maintenance cost was $6662 over the 20 years of operation. The total cost per kWh (COE) of the system was $8.47, which required 28.8 kW of photovoltaic cells and a 2-unit 10 kWh wind turbine with a 13.6 kW converter. The table below indicates the optimal solutions for the second scenario, i.e. grid connected mode.