au Renewable Energy Inc.
KDDI Corporation
Tokyo Electric Power Company Holdings, Incorporated
ENERES Co., Ltd.

au Renewable Energy Inc., KDDI Corporation, Tokyo Electric Power Company Holdings, Incorporated, and ENERES Co., Ltd. will begin a storage battery business (hereafter “this business”) in the second half of FY2025 with au Renewable Energy as the business entity.
Construction of storage battery facilities will begin in December 2024 with the installation of au Renewable Energy’s first large-scale storage battery (generation output 1,999 kW, storage capacity 5,608 kWh) at the KDDI Oyama Network Center (Oyama City, Tochigi Prefecture)^[1].

In this business, large-scale storage batteries will be directly connected to the power grid to contribute to power stabilization through various power market transactions, such as supplying balancing capacity ^[2] when power supply becomes tight.
In this business, au Renewable Energy will be the storage battery operator, Tokyo Electric Power Company Holdings will handle storage battery system design and equipment maintenance utilizing grid operation know-how and lithium battery knowledge, and ENERES will handle operations necessary for power market trading and storage battery charging/discharging control.
KDDI aims to achieve carbon neutrality for the KDDI Group by the end of FY2030. Through this business, we will accumulate comprehensive knowledge of the large-scale storage battery business and proceed with initiatives contributing to carbon neutrality achievement, such as supplying power value created by solar power generation during the day to KDDI facilities’ nighttime power demand.
Tokyo Electric Power Company Holdings will build stable energy supply systems by utilizing knowledge and technical capabilities cultivated in the electric power business to meet customer needs for improved renewable energy usage rates and BCP measures while maintaining power supply-demand balance. Through this business, the four companies will accumulate knowledge of the large-scale storage battery business including power market trading and collaborate as a medium to long-term project toward achieving carbon neutrality while maximizing each company’s knowledge.

■Power Plant Overview

Location	1919-1 Hitotonoya, Oyama City, Tochigi Prefecture (Within KDDI Oyama Network Center premises)
Operation Start Month	October 2025 (planned)
Equipment Specifications	Generation output 1,999 kW / Storage battery capacity 5,608 kWh
Site Area	324 square meters

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[1]Selected for FY2023 “Grid-Scale Large-Scale Storage Battery Introduction Promotion Project” by Tokyo Environmental Public Service Corporation

[2]Balancing capacity is an important concept for maintaining stable power supply and demand. It plays a role in filling the gap between power supply and demand for stable power grid operation. Balancing capacity providers (mainly power generators) supply balancing capacity to maintain power grid stability.