Osaka Gas and Sonnedix to build BESS at 38.7MW solar PV project in Japan

November 6, 2025
Facebook
Twitter
LinkedIn
Reddit
Email
A Sonnedix project.
Sonnedix Japan has brought online just under 500MW of solar PV in the country. Image: Sonnedix.

Utility Osaka Gas and developer Sonnedix are installing a battery energy storage system (BESS) at the latter’s 38.7MW Oita solar project, which Osaka Gas described as the largest battery storage facility to be co-located with renewable energy generation in Japan so far.

The two companies announced on 4 November that their jointly operated business is constructing a 30MW/125MWh BESS at the Sonnedix solar PV plant in Kyushu, southern Japan.

This article requires Premium SubscriptionBasic (FREE) Subscription

Try Premium for just $1

  • Full premium access for the first month at only $1
  • Converts to an annual rate after 30 days unless cancelled
  • Cancel anytime during the trial period

Premium Benefits

  • Expert industry analysis and interviews
  • Digital access to PV Tech Power journal
  • Exclusive event discounts

Or get the full Premium subscription right away

Or continue reading this article for free

Construction began in October 2024, and the partners are scheduled to bring it into commercial operation in November 2026.

Sonnedix said the BESS will be paired directly with the solar PV plant and enable the optimisation of solar generation as “dispatchable, market-responsive power”.

The developer carried out a JPY21.4 billion (US$139.3 million) refinancing of the Oita solar plant, arranged by bank MUFG, which has been a consistent investor in energy storage projects overseas and more recently in Japan.   

Sonnedix Japan has brought online just under 500MW of solar PV in the country, along with 601.5MW of plants in its management. The Oita project is its only one in Kyushu to date, while the BESS retrofit to it marks the developer’s first BESS project in Japan.

US technology provider Tesla will provide its Tesla Megapack BESS solution, likely manufactured at its ‘Megafactory’ in Shanghai, China, from which Tesla’s energy storage division serves markets outside the US.

Engineering, procurement and construction (EPC) duties will be carried out by Japan’s Toshiba Energy Systems & Solutions Corporation. Osaka Gas will carry out route-to-market (RTM) trading and optimisation of the battery asset.

Read the full version of this story on our sister site, Energy-Storage.news.

Read Next

December 12, 2025
A round-up of news coming from Europe, with IPP Encavis acquiring a 265MW solar PV portfolio in Italy, Iberdrola starting construction on 366MW of solar PV in its home country and IPP Sonnedix signing a renewables supply agreement with a subsidiary of Volkswagen in Spain.
December 12, 2025
US solar PV module prices have stabilised at just over US$0.28/W in the three months to November 2025, according to Anza.
Sponsored
December 9, 2025
Tongwei used its Global Partner Summit to show how high-efficiency PV, digital manufacturing and biodiversity protection must advance together.
December 9, 2025
ACWA Power and Bapco Energies have signed an agreement to build a 2.8GW solar plant in Saudi Arabia, to be co-located with a BESS.
December 5, 2025
WBS Power has sold the 150MW solar, 500MW/2,000MWh BESS Project Jupiter in Brandenburg, Germany, to investor Prime Capital.
December 4, 2025
Australia generated 5,271GWh of utility-scale solar PV and wind power in November 2025, a 28% increase from the same period last year.

Upcoming Events

Upcoming Webinars
December 17, 2025
2pm GMT / 3pm CET
Solar Media Events
February 3, 2026
London, UK
Solar Media Events
March 24, 2026
Dallas, Texas
Solar Media Events
April 15, 2026
Milan, Italy
Solar Media Events
June 16, 2026
Napa, USA