Technical Verification Project on Battery Sharing in Miyakojima City

- To contribute to the improvement of energy self-sufficiency on Kurimajima Island using virtual power plant technology -


Renewable Energy

R & D / Technology

December 19 2019

Miyakojima City
Toshiba Infrastructure Systems & Solutions Corporation
Toshiba Energy Systems & Solutions Corporation

Okinawa, Japan―Miyakojima City, NEXTEMS, an electricity service company in Okinawa, and Toshiba Group (Toshiba Infrastructure Systems & Solutions Corporation and Toshiba Energy Systems & Solutions Corporation) have started a technical verification project on a battery sharing system at Kurimajimai island in Miyakojima City from January 6 to January 31, 2020. The battery sharing system can charge and discharge surplus electricity at photovoltaic generation facilities (PV) using large size batteries and the existing electric power system.

Miyakojima City and Toshiba Group installed large storage battery systems with a capacity of 176 kWh at Kurimajima island in 2014 and ran a demonstration experiment called the “100% Renewable Energy Self-Support Demonstration Experiment,” aimed at providing all of the electricity consumed on the island with renewable energy and stationary storage batteries, and confirmed its usability. Furthermore, they also aimed at providing practical use of surplus power absorption at normal times.

The parties will install the gateway devices to watch the surplus power at 40 municipal housing locations in Miyakojima City. The virtual power plant system, which is owned by Toshiba Group, controls these gateway devices to charge and discharge batteries in minutes based on the surplus power of each base and the battery capacities. For this technical verification, a feasibility study of quick response control will be conducted within 30 minutes, including regarding the influence of electricity loss in the process of charging and discharging the batteries and the current planned value balancing system.*

Miyakojima City announced the “Declaration of Eco Island Miyakojima 2.0” in 2019 to clarify the vision of the original “Declaration of Eco Island Miyakojima,” which was announced in 2008. In this proclamation, Miyakojima City stated that they would increase the energy self-sufficiency ratio of the city from 2.9% in 2016 to 48.9% in 2050. However, renewal energy output is influenced by weather conditions, so batteries and other adjustment devices are needed for a uniform output rate. On the other hand, high introduction costs prevent the widespread use of battery systems.

Based on the results of this verification study on the efficiency of battery sharing, BCP purpose batteries installed in public facilities can be used for multiple purposes when the batteries are in standby mode. The introduction of batteries promotes further applications of renewal energy and can contribute to creating a stable electric power supply and increasing self-sufficiency ratios in the electric energy supply.

*In this system, power generation companies and electricity retailers adjust their power generation electricity consumption plans and their results every 30 minutes.

Large battery system installed in Kurimajima island, Miyakojima City

Large battery system installed in Kurimajima island, Miyakojima City

Outline of verification

1. Schedule
 January 6 to January 31, 2020

2. Role of each organization
 - Miyakojima City
  Responsible organization for the improvement of the self-sufficiency rate of energy on the island
  Gathers surplus electricity of PVs
 - Toshiba Group
  Construction of the virtual power plant system and support of management of the verification

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