Fiiu Linninen

Senior Associate, Member of the Finnish Bar, Bachelor of Business Administration

Services

  1. Environment, Energy & Green Transition

Contact details

I advise clients on a wide range of legal issues related to the environment, natural resources and infrastructure in matters such as project planning and development, authority negotiations and procedures, administrative proceedings, business transactions and financial arrangements. My core expertise includes matters related to environmental and other permits, EIA processes, land use, environmental liability and nature conservation.

Prior to joining Castrén & Snellman, I worked at another business law firm, advising clients operating in sectors such as mining, forestry and energy. My clients include, for example, companies engaged in exploration and mining, ports and terminal operators, bioproduct plants, wind and solar power plants, and waste treatment and incineration plants.

I graduated from the University of Helsinki in 2020 with a Master of Laws degree. I also hold degree in business administration from a university of applied sciences, which has equipped me with an even better understanding of our clients’ business and needs.

Latest references

Nscale – Data centre project
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
Terrafame – Environmental and water management permit processes concerning the company’s entire operations and the KL1 side rock area
Castrén & Snellman successfully assisted Terrafame Ltd in environmental and water management permit processes concerning the company’s entire operations and the KL1 side rock area, on which the Supreme Administrative Court issued its decision on 12 February 2026 (KHO 366/2026 and 367/2026). The changes made to the decisions of the Vaasa Administrative Court as a result of Terrafame’s appeals, enable the company to implement its new strategy and develop its operations as planned. The decisions of the Supreme Administrative Court brought the nearly ten-year-long permit process to a close.
Case published 20.2.2026
Brookfield – EUR 1 billion holdco financing for DayOne Data Centers
We advised a leading global investment firm Brookfield, alongside a global sovereign wealth investor, on the Finnish law aspects of a EUR 1 billion holdco financing for DayOne Data Centers, a Singapore-headquartered developer and operator of hyperscale data centres. Structured as a seven-year secured holdco financing facility of €500 million, expandable to €1 billion – and secured by DayOne’s Finland platform – the financing will support the rollout of hyperscale developments in Lahti and Kouvola, providing nearly 300MW of planned capacity across Finland. The proceeds will also support DayOne’s global expansion across the EU and APAC, with flexibility to allocate to other key growth markets as required.
Case published 29.1.2026
castren snellman general atlantic iceye
General Atlantic – ICEYE’s EUR 1 Billion Series F Funding Round
We advised General Atlantic as the lead investor on ICEYE’s EUR 1 billion series F funding round, valuing the company at over EUR 10 billion. ICEYE raised EUR 450 million (USD 520 million) in a primary Series F funding round led by General Atlantic. Additional investors included Solidium, Tesi, Varma, Ilmarinen, Lifeline Ventures, Nokia, Qatar Investment Authority (QIA) and TCV. Together with a secondary placement, the total fundraising exceeds EUR 1 billion. ICEYE is the world leader in sovereign intelligence from space, providing continuous monitoring capabilities to detect and respond to changes in any location on Earth. The company operates the world’s largest and most advanced Synthetic Aperture Radar satellite constellation. General Atlantic is a leading global investor with more than four and a half decades of experience providing capital and strategic support for over 885 companies throughout its history. As of March 31, 2026, General Atlantic manages approximately USD 126 billion in assets across its investment strategies. We advised General Atlantic on this transaction in collaboration with the international law firm Paul, Weiss, Rifkind, Wharton & Garrison.
Case published 9.6.2026
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.
Case published 5.6.2026
United Bankers – Sale of three care properties
United Bankers – Sale of three care properties
We advised United Bankers on the sale of three care properties to Kinland AS. The buildings were completed between 2021 and 2022 and meet high technical and environmental standards. All three properties are fully leased. The portfolio has a weighted average unexpired lease term of 13 years.
Case published 1.6.2026
Hiab acquisition financing
Hiab – Financing for USD 1,035 million acquisition of Labrie Environmental Group
We are advising Hiab Corporation in the financing for its USD 1,035 million acquisition of Labrie Environmental Group, a leading North American refuse collection vehicle (“RCV”) manufacturer, from Wynnchurch Capital, L.P. Hiab Corporation (Nasdaq Helsinki: HIAB) is a leading provider of smart and sustainable on-road load handling solutions, with 2025 sales of approximately EUR 1.6 billion and approximately 4,000 employees, operating through a global network spanning over 100 countries. Labrie Group is a leading North American provider of RCVs, employing approximately 1,200 people. 
Case published 1.6.2026
Lenders to ICEYE – EUR 300 million revolving credit facility for ICEYE
We advised an international bank syndicate in a EUR 300 million revolving credit facility (RCF) for ICEYE, the world leader in sovereign intelligence from space. The bank-syndicate comprised Nordic and global banks, with Citi and Danske Bank acting as Joint Global Coordinators and Mandated Lead Arrangers. The RCF will support the issuance of guarantees for customer contracts, enable continued business growth, and serve as a liquidity backstop. 
Case published 21.5.2026

Get to know our other experts in the field

Marius af Schultén
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 +358 40 565 7034
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 +358 50 460 3771
Minttu-Maria Miettinen
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Primary service Environment, Energy & Green Transition
 +358 20 776 5062
Konsta Peussa
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Primary service Environment, Energy & Green Transition
 +358 45 788 18016