Nagano Prefecture’s Public Enterprises Bureau commissioned the 1.5MW Cosmo no Shizuku Power Plant in Iijima Town on October 1, 2025. On the same day, it began supplying its output to Seiko Epson’s Ina Plant under a physical off-site PPA sleeved by Chubu Electric Power Miraiz.
According to the parties’ statement, Cosmo no Shizuku was developed as part of the Shinshu Green Power Expansion Project that they launched in May 2021. The scheme was set up to reinvest a portion of revenues from the prefecture’s hydropower plants into building new and repowering existing assets.
The Public Enterprises Bureau expects the power plant, which was initially scheduled to come online in 2024, to generate about 5.5GWh annually. Output exceeding Ina Plant’s consumption will be supplied to Seiko Epson’s other facilities in the prefecture.
METI data shows the bureau certified a 1.7MW project at Cosmo no Shizuku’s location under the feed-in-tariff (FIT) scheme in FY2021 when 1MW to 5MW hydropower plants were offered 27 yen per kWh compared to FY2025’s 23 yen per kWh. The certification was removed from the ministry’s database in July 2025. It is unclear whether the prefecture has recertified the asset under the feed-in-premium (FIP) scheme.
Cosmo no Shizuku is the first Nagano Prefecture-owned asset and the fourth project overall completed as part of Shinshu Green Power Expansion. It follows Chubu Electric Power’s newly developed 170kW Kurokawadaira and 5.6MW Seinaiji commissioned in July 2021 and October 2023, respectively, and the Futamata Power Plant repowering project completed in December 2023, which increased its output from 5.2MW to 6.9MW. All three operate under FIT.
The repowering project was done after five other companies including Kissei Pharmaceutical, KITZ, KOA, The Hachijuni Bank, and Yuwa joined the initiative in November 2023. At the same time, the prefecture said it would also develop another 860kW hydropower plant in Nagano City by FY2025.
Nagano’s Public Enterprises Bureau expects its hydropower plant portfolio to comprise of 36 assets totaling 111.5MW at the end of FY2025, up from 14 assets totaling 99.1MW at the end of FY2015. Separately from the Shinshu Green Power Expansion Project, it is also building a 2MW asset in Komagane City, which it expects to commission in 2028, and has been repowering the 23.6MW Haruchika and the 12.2MW Miwa, both originally commissioned in 1958.
