Three Solar-Integrated Battery Storage Projects Commence Operations in Kyushu

■ Overview

Blue Sky Energy Co., Ltd. has completed the construction of battery storage facilities integrated with existing solar power plants in Oita and Kagoshima Prefectures and has commenced operations sequentially.

This project was implemented following its selection for the Ministry of Economy, Trade and Industry's 'Support Project for the Introduction of Battery Storage Integrated with Renewable Energy Power Sources' (*1). With the start of operations, the power sales method for the subject power plants has transitioned from the FIT system (*2) to the FIP system (*3).

■ Background and Purpose

With the expansion of renewable energy, the Kyushu area in particular frequently experiences 'output curtailment' (*4), where solar power generation is restricted during periods when supply exceeds electricity demand. Conversely, during the evening and night when solar output drops, there is a shortage of renewable energy supply, requiring grid balance to be maintained through adjustments at thermal power plants.

By integrating battery storage with solar power plants, surplus electricity during curtailment periods can be stored and discharged when demand is high, enabling both the effective use of renewable energy and the stabilization of the power grid.

■ Project Summary

The three facilities that have commenced operations have a total solar power output of approximately 6 MW and a total battery capacity of approximately 25 MWh, with an expected annual power generation of approximately 7 million kWh (equivalent to about 2,000 average households *5).

■ Key Features of the Project

1. Avoidance of Output Curtailment and Maximization of Renewable Energy: Surplus electricity that would have been lost due to curtailment is stored in batteries and discharged during peak demand hours, significantly improving renewable energy utilization efficiency (time-shift operation).

2. Contribution to Grid Stabilization: In addition to addressing output curtailment, the batteries mitigate fluctuations in solar output caused by weather, contributing to grid stability. Integration with the wholesale electricity market and supply-demand adjustment market helps optimize the power supply-demand balance.

3. Market-Linked Operation Utilizing the FIP System: By transitioning from the FIT to the FIP system, optimal charge/discharge control is implemented based on wholesale electricity market price trends. This market-linked operation—charging when prices are low and discharging when they are high—promotes business viability and integration into the power market.

4. Advanced Operation via Remote Monitoring and Control: Optimization of charge/discharge plans based on AI-driven power generation and market price forecasting, combined with a 24-hour remote monitoring system, ensures stable operations.

■ Future Outlook

The company aims to achieve both the expansion of renewable energy and its stable supply by actively promoting the installation of battery storage systems. We aim to develop 100 such sites by 2029. Furthermore, we will continue to refine our expertise in market-linked operations utilizing the FIP system.