8.12.2022

Oomi – Construction of solar parks

We are assisting Oomi in a collaboration project, in which Oomi will construct several solar parks for Oulun Seudun Sähkö. The project will add 100 megawatts to Finland’s solar power capacity. At the end of 2021, a total of approximately 395 megawatts of solar capacity were connected to the grid.

The planning is already well underway. The first land acquisitions and building permits are ready and waiting for investment decisions. The investment amounts to over EUR 50 million in total.

Oomi Oy provides electricity contracts, solar power systems and electric vehicle charging solutions for both consumers and business customers in Finland. The company has over 400,000 customers and approximately 50 employees.

Latest references

We advised Delta Capacity AG in a project financing of two battery energy storage systems (BESS). The financed projects are among the largest BESS developments in Finland to enter construction with 250 MW / 600 MWh combined capacity. The financing was provided by Société Générale with support from Finnvera. Construction of both projects, located in Lapinlahti and Teuva, has already begun and the commercial operations are targeted to commence in late 2027 with partial tolling agreements already in place for both assets. The project in Lapinlahti is executed in partnership with Covenergo, while the project in Teuva is executed in partnership with Strioga Family Foundation. Delta Capacity is a Swiss developer of utility-scale battery storage systems. The projects strengthen Delta Capacity’s growing Nordic portfolio and support the flexibility of Finland’s electricity system by adding energy storage capacity, enabling production optimization as well as participation in electricity markets and reserve services.
Case published 28.10.2026
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
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.
Case published 5.6.2026
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