Kyuden Mirai Energy plans to conduct a demonstration operation of grid-scale battery storage in conjunction with Photovoltaic (PV) power plant in Omura City, Nagasaki Prefecture in FY2025.

The company will verify a scheme in which the battery is charged using PV generated electricity during the daytime and then discharged and sold in the evening. Additionally, the demonstration will evaluate a business model for optimized battery operation, enabling participation in both the wholesale power market and the supply-demand adjustment market under the Feed-in Premium (FIP) program. This initiative marks Japan’s first multi-use operation, designed to optimize electricity management across both the wholesale electricity market and the balancing market.

For this demonstration, the company will install a battery energy storage system (BESS) with an output of 1,990-kW and a rated capacity of 7,404 kWh at the Omura Mega Solar No. 4 Power Plant. The system will time-shift power generation by storing solar energy generated during the daytime, when output control measures are often applied, and discharging it in the evening, when energy demand is higher. 

In the Kyushu area, a large surplus of renewable energy such as solar power generation often leads to output control during the daytime, while there is a shortage of renewable energy in the evening and nighttime as solar power generation declines.   This project aims to maximize renewable energy utilization by minimizing daytime curtailment and selling stored electricity during peak demand hours. Additionally, the demonstration involves shifting from FIT system to the Feed-in Premium (FIP) system, where electricity is sold in the wholesale power market with a premium.

As Japan accelerates its shift to renewable energy, it is crucial to balance stable power supply and market price optimization. Multi-use battery storage operation involves trading in both the supply-demand adjustment market and the wholesale power market. This demonstration project will test an optimal multi-operation model that enhances profitability in the wholesale electricity market while supporting a sustainable power supply in the balancing market.

This will be the first business model in Japan to optimize the operations across two electricity markets and maximize profits from the use of storage batteries in conjunction with solar power. This initiative holds significant importance for Japan’s energy market.

Project Overview: Omura Mega Solar Power Plant No. 4

Location:  Juko-machi, Omura City, Nagasaki Prefecture (Approx. 32,000 m²)

Operator:  Kyuden Mirai Energy Corporation

Generation Capacity:  1,990kWAC (panel capacity: 2,730kWDC)

Annual Output:    2.7GWh (FY 2023 actual)

Battery Energy Storage System (Planned)

Output and Rated capacity:  1,990kW, 7,404kWhn (3.7hours)

Location: Omura Mega Solar Power Plant No.4

Start of operation: Within FY 2025