Osaka Gas acquired 40% of the 40MW Soma Tsubota Solar Power Plant in Soma City, Fukushima Prefecture, from a Sonnedix affiliate, the company announced on June 27, 2025. The deal expands their joint 40:60 portfolio to seven projects totaling more than 250MW.
METI data shows the power plant, owned by the SPC Soma Solar LLC, was FIT-certified in FY2012, the scheme’s inaugural year, and is under a 40 yen per kWh contract valid until August 2040. Osaka Gas said it will purchase the asset’s output through a specific wholesale supply contract with Tohoku Electric Power Network for resale to its customers alongside associated non-fossil certificates (NFCs).
Under the specific wholesale supply scheme, the grid operator sells power from a specific feed-in-tariff (FIT) plant to a retailer designated by the asset owner instead of into the spot market. The NFCs need to be procured by Osaka Gas separately through a quarterly auction.
The power plant was commissioned in February 2022 and, according to earlier Sonnedix statements, is expected to generate about 48GWh annually. It uses 400W Hanwha panels and 2.5MW TMEIC inverters. Daiwa House handled the project’s engineering, procurement, and construction (EPC).
Osaka Gas began acquiring 40% stakes in Sonnedix-led operational FIT projects in 2022, starting with a portfolio of three assets totaling 131MW. A 42MW project in Tochigi Prefecture followed in 2023 and two projects with a combined capacity of 40MW in 2024.
According to the latest statement, Osaka Gas and Sonnedix are also weighing co-locating their jointly owned assets with battery storage and developing new projects for corporate PPAs.
