This paper shows the result of performance evaluation of PEM (Proton Exchange Membrane) type water electrolyzer. In the previous studies, when fluctuating power was supplied to the water electrolysis cell, decrease in the effective area of the platinum catalyst by formation of oxide has probably occurred because increase in the resistance of the charge transfer at interface between electrode and electrolyte was observed by the Cole-Cole plot diagram. If the electrolysis time is long, the efficiency decreases by the formation of oxide film progresses. Therefore, the purpose of this research is to analyze the equivalent circuit in PEM type water electrolyzer using an electrochemical measurement method and to evaluate charge transfer resistance. In this paper, the electrolysis time in the experiment is 5 minutes, 10 minutes or 15 minutes, and supply voltage is constant voltage and fluctuation voltage. After water electrolysis, analyze the equivalent circuit using a chemical impedance analyzer. From the Cole-Cole plot diagram obtained by this analysis, progress of oxide film formation due to the length of electrolysis time was observed.

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The purpose of this study is to propose a renewable energy equipment which is the most suitable performance according to the heat load of small and medium enterprises. As the first step of this study, we developed a numerical simulator of a heat supply system consisting of a solar collector and a geothermal heat pump for small and medium enterprises. The numerical simulator was constructed by modeling heat quantity obtained from equipment such as solar collector, heat quantity stored in heat storage tank, and heat load such as cooling / heating load. We can perform the one-year operation simulation of the heat supply system by inputting the building size and the equipment capacity such as the number of solar collectors by using the numerical simulator. As a future prospect, we aim to implement the function to automatically determine the optimum equipment capacity by installing artificial intelligence in a numerical simulator.

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An operations management framework for energy supply networks is developed to improve their operation performances under uncertain input conditions. The developed management hierarchically integrates forecast scenario generation of input conditions, operation schedule planning using a two-stage stochastic mixed-integer linear programming approach, and real-time control based on operation rules. The forecast scenario generation and stochastic schedule planning are updated using a receding horizon approach. The developed management is applied to a residential energy supply network, consisting of shared photovoltaics, multiple sets of a heat pump unit and hot water storage tank, and a shared battery unit to supply power and hot water to multiple dwellings. The annual operating simulation reveals the impact of the selling price setting of photovoltaics output on the operation performances. Moreover, the appropriate range of the selling price setting for the operating cost reduction in the target energy supply network is clarified.

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