TESS Engineering will build 20MWDC solar power plant under an on-site PPA with Toyo Tanso, a TSE Prime-listed carbon products manufacturer, its parent TESS Holdings announced on May 26, 2025.
The Japan Energy Hub PPA database shows it is the second largest disclosed on-site deal, only trailing a 22.9MWDC project at Osaka Kansai Airport by an Orix subsidiary
According to TESS Holdings’ statement, the ground-mounted solar plant will build on 14,000m2 of unutilized land at Toyo Tanso Takuma Division in Mitoyo City, Kagawa Prefecture. TESS Engineering plans to commission the asset, which is expected to generate about 27GWh annually, in June 2027. The companies did not disclose the share of the division’s power consumption the PPA will cover.
The power plant will comprise 30,072 665W Aiko Energy panels.
This is Toyo Tanso’s first disclosed PPA. The deal increases TESS Engineering’s signed on-site capacity by over 35%, from 54.8MW across 47 offtakers as of the end of March 2025. It is also the company’s largest on-site project to date, surpassing a 13.4MW agreement with DMG Mori Seiki. Its other projects range between under 100kWDC and about 3MWDC in size.
With land for utility-scale solar in short supply, some developers are finding an opportunity in identifying and signing on-site PPAs with industrial companies holding underutilized land adjacent to their factories. Other recent examples, albeit significantly smaller, include a 5MWDC deal between Hokuriku Electric Power Biz Energy Solution and Toray, and a 4.8MWDC project by SMFL Mirai Partners on YKK AP’s premises.
