Between the end of January and mid-February 2025, TESS Engineering and Energy Power disclosed major EPC deals for battery storage projects expected to commission by mid-2026.
TESS Engineering announced its 5.6 billion yen on January 31, 2025, though the official contract is yet to be finalized. The agreement is expected to involve adding BESS to five existing solar projects operated by the unnamed customer. One of the projects is owned by the customer directly. Contract for the remaining four will be signed with the projects’ lessor. TESS Engineering aims to complete the projects in January 2026.
Energy Power’s approximately 4 billion yen deal with an unnamed customer, which was disclosed on February 14, 2025, appears to involve the installation of BESS at one or multiple standalone grid-scale storage facilities. While the company did not disclosed the planned completion date, its statement says the revenue is expected to be recognized in its next fiscal year, ending August 31, 2026.
As part of its mid-term “TX2030 TESS Transformation 2030” plan, TESS Engineering’s parent TESS Holdings is looking to grow its involvement in grid-scale BESS projects and FIT-to-FIP solar project conversions involving the addition of storage.
Starting at zero as of the end of June 2024, TESS Holdings aims to construct 220MW of mainly grid-scale batteries by FY2026 (ending in June 2027) and 850MW by FY2029 (ending in June 2030). It also aims to convert 75MW of its own power plants from FIT to FIP by FY2026 and 113MW, or approximately half of the capacity it owned as of the end of June 2024, by FY2029.
In addition to providing EPC services to third parties, both TESS Holdings and Energy Power are also developing their own projects.
In February 2025, the former announced a partnership with Daiwa Energy & Infrastructure as part of which the companies aim to commit to 2GWh of grid-scale BESS projects within three years. At the end of last year, Tokyo Century acquired a minority stake in TESS Holdings as part of a broad renewables-focused partnership that also involves the development of grid-scale BESS projects.
Energy Power said late last year that it would be acquiring two 1.98MW/8.23MWh projects in the Kansai TSO area, which it expects to commission by the end of August 2026.
Japan’s growing solar and wind capacity alongside its shift from the pay-per-kWh FIT subsidy scheme to the FIP scheme that requires owners to maximize their assets’ value through commercial are creating an increasing demand for battery storage. The two EPC deals highlight this trend.
