The Installation of a Hybrid Battery for Expansion of Renewable Energy Introduction in Oki Islands

The Chugoku Electric Power Company, Incorporated

Overview of major power facilities in the Oki Islands

Hybrid BESS (Battery Energy Storage System)

Configuration diagram of energy management system (EMS)

Outline

On remote islands that are not connected by transmission lines to mainland Japan, like the Oki Islands, the effect due to fluctuation in the amount of energy generated is significant due to the small scale of electricity usage. Therefore, in order to expand the introduction of renewable energy on remote islands, measures are required to establish batteries to adjust the fluctuation in the amount of renewable energy generated.
This project is a plan adopted for subsidization by the Ministry of the Environment in FY 2014* which aims, for the first time in Japan, to introduce a hybrid battery system combining NaS and Li-ion batteries, 2 different types of batteries, to receive a total of 11,000 kW of renewable energy exceeding the Oki Islands' annual minimal demand of 10,000 kW.
*FY 2014 battery demonstration project for promoting the introduction of renewable energy on remote islands

Description

1. Attainment Target in the Challenge
By installing a "hybrid battery system" combining NaS and Li-ion batteries, 2 different types of batteries, we aim to reduce the initial cost, improve system efficiency, and improve charge/discharge management of NaS batteries, while also unifying control of the internal combustion generators and absorbing surplus power and frequency fluctuation as we engage in automated operation, ultimately leading to the expansion of renewable energy introduction.
Furthermore, as we introduce renewable energy, we held open recruitment for businesses with cooperation from the local government, promoting PR activities united with the community.
As a result, we expanded the amount of renewable energy introduced from approx. 2,300 kW before the project started to approx. 8,000 kW over a short period of time.
We will continue to contribute to the reduction of carbon dioxide emissions by promoting the introduction of renewable energy, while ensuring the quality of electricity through the use of the hybrid battery system.

2. Issues to Overcome in Achieving the Challenge
As the Oki Islands are remote islands with an electric system that is not connected to mainland Japan, they are characterized by the small-scale electricity usage and the fact that fluctuation in power demand or energy generation significantly affects the quality of electricity.
With renewable energy such as photovoltaic or wind power, the amount of energy generated significantly fluctuates due to conditions in nature. Therefore, a measure to handle fluctuations in the amount of renewable energy generated using batteries and the like is necessary to further expand the introduction of renewable energy.

3. Detailed Actions
(1) Leading effort for introducing the first "hybrid battery system" in Japan
・ In order to find a low-cost response to both "quick and small fluctuations (short term fluctuations)" and "slow and large fluctuations (long term fluctuations)" in renewable energy generated amounts, we constructed a "hybrid battery system" that combines 2 different types of batteries, the first effort of its kind in Japan.
・ We connected the batteries, diesel power station, and renewable energy facilities to an Energy Management System (EMS) via a communication network, achieving supply-demand operation that automatically controls the batteries and internal combustion generators from the EMS while including data such as the power demand and system frequency, all on a commercial-use power system.
・ We will continue to promote the introduction of renewable energy, while ensuring the quality of electricity through the use of the hybrid battery system.

(2) Efforts united with the community
・ With cooperation from the local government, we held open recruitment for a renewable energy company at the former grounds of the airport and introduced a large-scale mega solar farm.
・ We will continue to promote efforts united with the community by using a special website, PR Hall, and the like to not only introduce this project but also to showcase the beauty of the Oki Islands with the approach of "the fusion of cutting-edge technology and vast nature."

4. Quantitative Effect When the Challenge Is Achieved
・ Improvement in supply stability for electricity
On the Oki Islands that are not connected to mainland Japan by transmission lines, we will improve the stability of electricity on the Oki Islands by installing new renewable energy facilities and batteries.
・ Reduction of burden on global environment
By reducing the amount of energy generated by diesel generation through expanding the introduction of renewable energy, we will cut carbon dioxide emissions and contribute to the prevention of global warming.
・ Increasing community vitality

This project is a leading effort, the first of its kind in Japan, and has been visited by many people.