ROUNDUP: Japan’s BESS market sees domestic and overseas players pursue larger-scale projects

Domestic BESS integrator PowerX receives 230MWh project order

A trio of major Japanese investors and holding companies have ordered battery energy storage system (BESS) units totalling 230.1MWh from Tokyo-headquartered startup PowerX.

PowerX, which launched in 2021 with a novel proposal to transfer stored electricity from offshore wind farms via batteries on ships, has since listed on the Tokyo Stock Exchange (TSE) and begun assembling and integrating solutions for electric vehicle (EV) charging and grid-scale BESS.

While most of its recently announced deals have been for projects of the aforementioned 2MW/8MWh sizing, the company said yesterday (1 June) that Mitsubishi Estate, Itochu Corporation and Tokyo Century Corporation have ordered 102 units of PowerX’s Mega Power 2500 10-foot ISO-standard containerised BESS.

The trio are jointly developing their project in Chikuzen, Fukuoka, on the southern Japanese island of Kyushu, a hotbed for renewable energy development.

The 230MWh of batteries will be paired with power conversion systems (PCS) of 67MW output. The Fukuoka Prefecture Chikuzen Town Energy Storage Station is expected to begin commercial operation in January 2028, which is in the latter half of Japan’s 2027 financial year.

PowerX’s BESS is assembled in Okayama Prefecture, Japan. It utilises lithium iron phosphate (LFP) cells. The company noted in a release that the solution was developed in partnership with Itochu Corporation, already a big player in Japan’s residential battery market and an investor in grid-scale BESS overseas.

The Chikuzen project was selected to receive subsidy support under the government Ministry of Economy, Trade and Industry (METI) scheme to promote electricity storage facilities. The subsidy offers Capex support, but a portion of profits earned in-market must be returned to the state.  

Tokyo Century said in a separate announcement yesterday that construction officially began on the project with a ground-breaking ceremony held 13 May. The leasing and financial services company said its social infrastructure group identified grid-based battery storage as one of its main priority businesses, within a Tokyo Century medium-term management plan to 2030.

Eku Energy acquires land for 120MWh project in Gunma Prefecture

The Japanese subsidiary of London-headquartered BESS developer Eku Energy has agreed to acquire land for a 30MW/120MWh BESS project in Gunma Prefecture.

Eku Energy’s Naganohara BESS would be built in the town of the same name, roughly 160km northwest of Tokyo. The land purchase agreement signed with Gunma Prefecture’s enterprise bureau is the culmination of a three-year collaboration, the developer said.

Operations are scheduled to begin in 2029. It is Macquarie-backed Eku Energy’s fourth large-scale BESS project to be announced in Japan. The company signed a tolling agreement for its first, Hirohara BESS, a project of the same 30MW/120MWh sizing, back in 2024.

Eku is also prominent in other markets, including Australia and the UK. In a February interview with ESN Premium, Eku Energy CEO Daniel Burrows discussed the parent company’s strategy of “long-term value creation,” viewing BESS assets as an infrastructure investment play.

Eku Energy Japan managing director Kentaro Ono and head of investment and origination Hirofumi Sho also spoke to ESN Premium, in a two-part deep-dive series into the emerging Japanese market.

Sho said at the time, in mid-2025, that while there is no broad consensus on exactly how much energy storage Japan needs to meet its energy security, system stability and renewable energy requirements, the fundamental drivers for adoption are strong.

Eku said last week (29 May) that the Naganohara BESS is being built within the service area of Tokyo Electric Power Company (TEPCO). The area has, since March 2026, seen output control (aka curtailment) applied to renewable energy generators. BESS assets will help integrate that power into the grid rather than have it go to waste.

“Grid-scale battery energy storage facilities must operate safely over the long term and earn trust as part of critical power infrastructure. We recognise the significant responsibility that comes with advancing this project on industrial land prepared by Gunma Prefecture,” Eku Energy Japan MD Kentaro Ono said.

“Through the Naganohara BESS project, we will continue prioritising safety and reliability while building trusted relationships with local communities. This project represents our long-term commitment to Japan and our ambition to help shape next-generation energy infrastructure together with local communities.”

Financial services major SMFL joins 70MWh project

Real estate, energy and environmental infrastructure company SMFL Mirai Partners is collaborating with the green energy subsidiary of investment and real estate firm SPARX Group on a 70MWh BESS project.

SMFL Mirai Partners is a subsidiary of Japanese financial services major Sumitomo Mitsui Finance and Leasing (SMFL). It is partnering with SPARK Green Energy & Technology on the 23MW/70MWh BESS project in Niigata Prefecture, on the Japan Sea coast of northwest Japan.

The project’s expected COD is May 2028. SMFL Mirai Partners will hold 52.6% of project equity and SPARX the remaining 47.4%.

SMFL Mirai Partners said it is targeting 1GW of BESS deployments by the 2031 fiscal year. The company said the Niigata project will help adjust the supply-demand balance of renewable energy on the grid.

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