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
Delta Capacity – Project financing of two battery energy storage systems (BESS)
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
Martela Corporation – Directed share issue and combination of share series
We acted as legal adviser to Martela Corporation in its directed share issue, through which Martela raised gross proceeds of approximately EUR 7.2 million to strengthen the company’s financial position and liquidity and to create headroom for continuing the necessary development and efficiency measures. In connection with the directed share issue, Martela’s unlisted series K shares, which carried greater voting rights, were combined with its listed series A shares. Following the combination, the company has only one share series, which is traded on the regulated market maintained by Nasdaq Helsinki Ltd, with each share carrying one vote and otherwise identical rights. Martela is a Nordic leader specialising in user-centric working and learning environments. With over 80 years of experience, Martela creates the best places to work and offers its customers the Martela Lifecycle solutions which combine furniture and related services into a seamless whole.
Case published 27.10.2026
Banyan Software – Acquisition of Carus Ferry
We acted as legal adviser to Banyan Software on its acquisition of Carus Ferry, a Finland-based provider of reservation, check-in and port operations software for ferry and passenger shipping operators. The acquisition further strengthens Banyan Software’s presence in the Nordic region while providing Carus with a long-term partner to support its continued growth and development. Carus was founded in 1998 and is headquartered in Mariehamn on the Åland Islands, Finland. The company develops mission-critical software for ferry, cruise and passenger shipping operators, covering the full passenger journey from booking and ticketing to capacity management, check-in and boarding. Carus also provides port automation, onboard sales systems and business information tools. The company serves approximately 30 operators across four continents and is the largest vendor by customer count in ferry reservation and departure control. Banyan Software is an acquirer and long-term operator of mission-critical software businesses serving specialised industries. Founded in 2016, Banyan follows a buy-and-hold-for-life approach and supports the long-term growth and development of its portfolio companies. Banyan operates more than 130 portfolio companies across North and South America, the United Kingdom, Europe and APAC. Following the acquisition of Carus, Banyan operates three businesses in the Nordic region.
Case published 20.10.2026
Move Energy – Combination of 3North Partners and Steady Energy and related private placement and IPO
We advised Move Energy as an investor in connection with the combination of 3North Partners Plc and Steady Energy Oy and the related private placement and initial public offering of the combined company on Nasdaq First North Growth Market Finland. In connection with the transaction, 3North Partners received approximately EUR 69.8 million in investor commitments from a group of institutional and other investors, including Move Energy, to fund the combined company. Steady Energy is a Finnish nuclear technology company developing a new generation of small modular reactors (SMRs) particularly suited for district heating. Its LDR-50 reactor is designed to provide cities and utilities with a scalable and low-carbon alternative to combustion-based heat production.
Case published 19.10.2026
Efima – Sale of AI business
We advised Efima Oyj on the sale of its AI business to Better Care Technologies Oy. The transaction included Efima’s Moiva AI platform developed for the care sector, the related technology and brand, customer contracts, and the experts working in the business. Efima is a Finnish digital company that supports the sustainable growth of large and mid-sized companies by streamlining their business processes and by creating competitive advantage through the innovative use of artificial intelligence and data. The company has nearly 200 experts based in Helsinki and Tampere. 
Case published 21.9.2026

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