OPTIMAL CONFIGURATION OF ENERGY STORAGE AND HYDROGEN PRODUCTION AT RENEWABLE ENERGY SITES IN A POWER SYSTEM WITHOUT FOSSIL FUELS IN JAPAN

In an electric power system consisting solely of non-fossil power sources, the capacity of storage batteries and hydrogen production facilities that should be attached to renewable energy power plants depends on the cost of these facilities and the cost of connecting them to the grid. In this study, assuming that a large amount of renewable energy will be introduced into the Japanese power system in 2050, the capacity and annual operation of storage batteries, water electrolysis equipment, hydrogen tanks, and transmission facilities that minimize costs were investigated. The results showed that solar photovoltaic (PV) plants require more variability mitigation equipment than wind farms. At a transmission cost of 1.2 JPY/kW/h, the optimal Li-ion battery capacity and transmission capacity for PV are 9.1 times and 0.18 times that for wind farms, respectively, and only PV is equipped with a 5 MW hydrogen production unit and 15 kNm³ of hydrogen storage.