5.6.2026

Oomi Solar Sale of a Solar Power Plant and Battery Energy Storage Project

We advised Oomi Solar Oy on the sale of a solar power park and battery energy storage project to Tuulipolar Oy. The transaction concerned a 24 MWp solar power plant and a 36 MW / 70 MWh battery energy storage system (BESS) to be constructed in Tornio. Tuulipolar Oy will act as the owner and operator of the plant, while Oomi Solar Oy will be responsible for its design and construction.

The project will form the world’s northernmost industrial hybrid power plant, contributing to Finland’s green energy transition by increasing renewable energy production and electricity storage capacity in Northern Finland. The hybrid solution enables optimization of production as well as active participation in electricity markets and reserve services, improving the project’s profitability and supporting the balance of the electricity system year-round. Electricity production from the hybrid plant is expected to begin in 2028.

Oomi Solar Oy is a Finnish renewable energy expert with experience from nearly 200 MW of installed solar capacity. The company helps businesses and communities accelerate the green transition by offering comprehensive solutions, including solar power plants, energy storage systems, and related lifecycle services from project development to maintenance. Oomi Solar Oy employs more than 20 energy professionals and delivers solar power projects across Finland. The company’s vision is to be Finland’s most desired partner for solar energy and energy solutions.

Latest references

We acted as Finnish law legal adviser to the lenders and the export credit agencies in connection with the EUR 514.4 million green project financing for the development and construction of Easpring Finland New Materials Oy’s cathode active material (CAM) manufacturing plant in Kotka, Finland. The borrower, Easpring Finland New Materials Oy, is a joint venture owned by Beijing Easpring Material Technology, Finnish Minerals Group and LG Energy Solution. The financing was provided by six international commercial banks, with Société Générale acting as financial adviser and mandated lead arranger together with Natixis as co-mandated lead arranger, and DNB, ICBC, ING and Standard Chartered participating as lenders, with support from the export credit agencies Finnvera and Sinosure. The project represents a significant milestone for Finland and the European battery value chain by strengthening Europe’s domestic supply of cathode active materials, a key component in lithium-ion batteries for electric vehicles and energy storage applications. Once the first phase of the project is operational, the Kotka facility is expected to produce approximately 60,000 tonnes of cathode active material annually, making it one of the largest CAM production plants in Europe and supplying leading battery manufacturers across Europe. 
Case published 21.7.2026
We acted as Finnish legal advisor to Delta Capacity in connection with its acquisition of the ready-to-build Karppio battery energy storage system (BESS) project from Helios Nordic Energy. The acquisition was made and the project will be implemented together with Strioga Family Foundation. The Karppio BESS project is located in Teuva, Finland, and has a capacity of 125 MW / 300 MWh. Delta Capacity will lead the remaining development of the project through to commissioning, planned for 2027, and will serve as long-term asset manager. Delta Capacity is a Swiss-based developer of utility scale battery storage systems. The acquisition adds to Delta Capacity’s growing Nordic portfolio. 
Case published 20.7.2026
Castrén & Snellman advised Nscale, a European AI infrastructure company, in connection with its planned data centre project in Harjavalta, Finland. The facility will be located in the Sievari industrial area. Castrén & Snellman’s advisory role encompassed the negotiation and execution of a site securing and development agreement (SSDA) with Fortum, as well as the preliminary land sale process for the Sievari site with the Town of Harjavalta. Under the SSDA, Fortum supports the advancement of Nscale’s project development, including grid connection design and permitting.
Case published 15.4.2026
We advised UK-based investment company Downing in its acquisition of the entire share capital of Tornionlaakson Voima Oy. Tornionlaakson Voima owns three hydropower plants in the Tengeliönjoki river system – the Portimokoski power plants in Ylitornio, the Jolmankoski power plants in Raanujärvi and the Kaaranneskoski power plants in Sirkkakoski. The power plants produce a total of approx. 45 gigawatt-hours of electricity per year. Tornionlaakson Voima’s daily operations will continue normally, and the transaction will not affect customers. The consummation of the transaction is subject to the approval of the Ministry of Economic Affairs and Employment. Downing has over 35 years’ experience in providing a wide range of investment solutions to the needs of institutional investors, advisers and retail investors. The company manages over £2 billion in assets in both the private and public markets and its current hydro power portfolio includes approx. 50 hydro power plants in the Nordics. 
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