Japan BESS: How Energy Vault, Trina Storage, Itochu tailor their projects to local grid

Energy Vault has completed its purchase of 350 MW/1 GWh of advanced-stage projects and 500 MW of early-stage projects from developer BayWa r.e. in Japan.

The assets in the advanced-stage portfolio are expected to begin construction in the second half of 2027, and enter commercial operations in mid-2028, providing Energy Vault with a smooth introduction to one of the world’s most dynamic energy storage markets.

Crucially, the projects in the advanced-stage portfolio in Japan have a three-hour duration, slightly longer than short-duration two-hour configurations common in the Texas grid.

“In California, you have a four-hour duration only because there is resource adequacy,” Marco Terruzzin, Chief Revenue Officer, Energy Vault pointed out to ESS News. Longer-duration BESS will provide more flexibility to Japan’s congested grid.

With an asset portfolio in hand and a local experienced team coming over from BayWa r.e., Energy Vault will explore tailormade technologies for Japan’s market.

According to Terruzzin, Energy Vault has refocused its attention on acquiring infrastructure and IPP activities rather than technology R&D. “We build, own, and operate sites where we install hybrid generation and storage technologies,” he said. The company has completed a spate of deals and acquisitions in the United States, including a deal with sodium-ion developer Peak Energy.

Energy Vault’s global asset portfolio – including assets in operation, under construction and acquired – stands at more than 1 GW, supporting more than $180 million in anticipated annual recurring EBITDA.

The Japan piece of the puzzle

ESS News reported on Energy Vault’s Japan-based acquisition in April but the identity of the party selling the assets was not named.

“Japan is a strategically important market for energy storage, and we are pleased to have successfully transferred this high-quality portfolio to Energy Vault,” said Daniel Gaefke, Group Chief Operating Officer of BayWa r.e. following the transaction.

“With its integrated technology platform, execution capability, and asset ownership strategy, Energy Vault is well positioned to advance these projects and support Japan’s energy transition,” Gaefke added.

Meanwhile, Trina Storage, the energy storage arm of Trinasolar, signed a contract for a 160 MWh ultra-high voltage BESS in Japan’s Kyushu region. The battery is scheduled for delivery in 2026 with COD planned for 2027.

According to Trinasolar Japan General Manager, Li Na, “Japan’s energy market is undergoing rapid change as renewable energy penetration increases, particularly in regions such as Kyushu.”

Delivery is planned for 2026, with COD expected in 2027. Trina Storage said it will ensure delivery is aligned with local regulations and grid interconnection procedures through its dedicated Japan team.

The company recently debuted the next generation of its Elementa Flex battery technology which is specifically designed for the Japanese market. The Elementa Flex 3 utility-scale system has around 1.56 MWh of capacity and weighs around 13 tonnes and is suitable for deployment in suburban environments.

The upcoming BESS project will use the existing Elementa Flex 2 product, however, which has a capacity of 5 MWh per unit and uses 314 Ah high-capacity cells.

And local market player Itochu Corporation has announced construction of a 67 MW/230.1 MWh BESS scheduled to begin commercial operations in Jan. 2028. It will also be deployed in Kyushu, where it will participate in Japan’s capacity market, wholesale electricity market, and balancing market.

The developer said it would contribute to local grid stability using Itochu’s AI-based optimization technology. Japan’s Ministry of Trade and Industry selected the project for its FY2025 Subsidy Program for the Promotion of Renewable Energy Development and Utility-Scale Battery Energy Storage Systems.