The Chugoku Electric Power Co Inc installed a "hybrid storage battery system" in the Oki Islands, Shimane Prefecture, Japan, and conducted a verification test of it from September 2015 to March 31, 2019.
The project was selected for the "Subsidy for Projects to Reduce CO2 Emissions, Etc (Storage Battery Verification Project for Promoting the Introduction of Renewable Energy in Isolated Islands)" of Japan's Ministry of the Environment.
This time, Chugoku Electric Power submitted a report on the project to the ministry. The company will continue to use the system.
The company set up the hybrid storage battery system in Nishinoshima-cho, Shimane Prefecture, and conducted the verification of technologies for (1) reducing the output fluctuation of renewable energy-based power generation facilities, which are influenced by weathers, etc, (2) efficiently charging/discharging and controlling storage batteries and so forth.
In isolated islands whose power grids are not connected to the mainland, the scale of power network is smaller than that of power network in the mainland, increasing the impact of output fluctuation. Therefore, for further introducing renewable energy, measures against output fluctuation are necessary.
Chugoku Electric Power combined two kinds of storage batteries with different properties. Specifically, lithium-ion (Li-ion) batteries and NAS (sodium-sulfur) batteries absorb short- and long-period fluctuations, respectively. The Li-ion battery is a 700kWh product (output: 2MW) of GS Yuasa Corp, and the NAS battery is a 25,200kWh product (output: 4.2MW) of NGK Insulators Ltd.