Maximizing power-supply time of DC power system with photovoltaics and fuel cells

We are currently investigating the specifications of the architecture and control method of a DC power system with photovoltaics and fuel cells that achieves longer power-supply time with limited stockpiling-energy without grid power. For this paper, we focused on the case in which electric power needs to be constantly supplied to a load but photovoltaic power generation is unstable. We applied (1) fossil-fuel-driven FCs, (2) fossil-fuel-driven FCs that charge in parallel, and (3) hydrogen-driven FCs as the power-assisting method and calculated the fuel efficiency in each method. We discuss the effect of each power-assisting method on power-supply time. The results imply that choosing a charge-in-parallel or hydrogen-driven fuel-cell method as the power assistant is effective in lengthening power-supply time.