Samuli Tarkiainen

Partner, Member of the Finnish Bar

I believe that the best results in any project – be it a re-domiciliation of a corporation, the construction of a power plant or an investment into infrastructure assets – can be achieved through business understanding, focusing on the solutions and being pragmatic. In fact, this is true in all situations where we are on board as counsel. And of course, the fundamental core we provide is market-leading legal expertise.

During my practice as an attorney and in-house lawyer, I have gained extensive experience of industrial projects and contracts as well as corporate transactions and restructurings, especially in the energy industry and the financial sector.

It has been very inspiring to provide strategic legal advice on certain key energy and infrastructure projects – green and brownfield, joint ventures, public private partnerships, and consortiums – and on various purchasing, delivery, outsourcing and other contracts. From the field of energy, my experience includes many types of renewable energy technology, such as solar, wind, biomass, biofuels, energy from waste, wave power, geothermal and hydro, as well as conventional power and CHP. I find it rewarding to be part of facilitating change and sustainability in our energy system.

I regularly represent major companies and international investors in public, private, venture capital and private equity transactions and restructurings, with a specific focus on industry, energy, utilities and regulated businesses. I have also been involved in compliance matters and practice in a broad range of business law.

Latest references

Castrén & Snellman is acting as the legal advisor to the City of Pori and Pori Energia Oy in the finance arrangement whereby debt facilities in the total amount of EUR 292 million are secured for the purpose of refinancing the existing liabilities and fuelling the future growth of Pori Energia. Pori Energia and its financiers signed a Finnish law governed facilities agreement for this purpose on 13 January 2025. Pori Energia, a multi-utility company, operates in various sectors including district heating, electricity distribution, and electricity generation through CHP and renewable sources. The company also provides wind power services and industrial energy solutions in the Satakunta region where it has c. 60,000 customers.
Case published 6.2.2025
Castrén & Snellman is acting as the legal advisor to the City of Pori in its sale of a 49% stake in Pori Energia to Polhem Infra. Pori Energia, a multi-utility company, operates in various sectors including district heating, electricity distribution, and electricity generation through CHP and renewable sources. The company also provides wind power services and industrial energy solutions in the Satakunta region. This strategic partnership between the City of Pori and Polhem Infra aims to enhance Pori Energia’s financial stability and investment capabilities, enabling the company to further its efforts in the energy transition and continue delivering high-quality energy services to its customers. Polhem Infra, owned by Swedish state pension funds, focuses on investments in critical infrastructure, including renewable electricity generation, energy storage, energy distribution, digital infrastructure, and transport infrastructure. The transaction values Pori Energia at EUR 905 million. 
Case published 31.1.2025
We are advising Oomi Oy in a business transaction whereby KSS Energia Oy’s consumer and business customers in the retail sale of electricity will be transferred to Oomi. The transfer is scheduled to take place in March 2025. The arrangement requires approval from the Finnish Competition and Consumer Authority. Oomi Oy is one of the largest energy service companies and electricity sellers in Finland. The arrangement is a result of the recent development of the electricity market and Oomi’s strategy, which aims to offer customers a seamless and improved digital customer experience.
Case published 20.12.2024
We acted as the lead counsel to Fortum in a cross-border transaction in which Fortum sold its recycling and waste business. The business was sold to thematic impact investing firm Summa Equity through its portfolio company NG Group. The debt-free purchase price is approximately EUR 800 million.  Fortum’s recycling and waste business to be sold comprises municipal and industrial waste management and end-to-end plastics, metals, ash, slag and hazardous waste treatment and recycling services. These businesses are located in Finland, Sweden, Denmark and Norway and currently employ approximately 900 employees.
Case published 18.7.2024
We advised Oomi Oy in a partial demerger where Oomi’s solar power business for corporate customers demerged and formed a new independent company, Oomi Solar Oy. As part of the partial demerger process, we assisted Oomi in pre-emptive discussions with the tax authorities where the tax treatment of the restructuring was confirmed. Oomi Solar, the demerged company, focuses on implementing solar power plants for real estate properties, ground-level solar power plants and industrial solar power parks and supports companies and entities in their transition towards renewable energy. Oomi Solar started operations on 1 January 2024.
Case published 12.2.2024
We are advising Oomi Oy in questions relating to electricity market legislation, consumer protection and marketing law. Oomi is one of the largest electricity sales companies in Finland. The company sells electricity contracts, solar power systems and electric car charging solutions to consumers and businesses.
Case published 19.6.2023
Valio is a food company with the courage to change with the times. Valio’s road to growth and towards the innovative transformation of the food industry is supported by its long-standing business law partner, Castrén & Snellman. Juha Hölttä became Valio’s General Counsel at a time when the company kicked its new strategy into a higher gear. ‘In the past two years we have made several significant market initiatives and expanded our business from food production to other areas of the value chain. By acquiring Heinon Tukku, we now provide a new kind of added value to restaurants and professional kitchens through our Valio Aimo ® wholesale business. And our joint venture with St1, Suomen Lantakaasu Oy, will enable us to reach our goal of turning manure into biogas for heavy transportation,’ Hölttä describes some of the milestones of the new strategy. In addition to expanding into new business areas, Valio continues to build a more sustainable dairy business alongside seeking international growth from plant-based products. Valio has invested in the international growth of its Oddlygood ® brand through incorporation and gained additional product development expertise through the acquisition of Gold&Green. Carbon footprint of milk reduced by new business operations Dairy products are at the core of Valio’s business, and the company develops this strong foundation not only through product innovation but also at the beginning of the food chain. ‘Who could have foreseen that dairy farm manure could become one way of tackling climate challenges? Our planned biogas plants will use manure and agricultural by-products to produce renewable liquefied biogas for use as transportation fuel,’ says Hölttä. ‘Valio is aiming for a carbon-neutral milk chain by 2035. We are making major reforms in our operations in order to make this happen.’ The sustainability programme for Valio’s 3,700 dairy farms has been expanded, and it now includes the preventive and systematic healthcare of cows as well as actions related to grazing, the climate and biodiversity. ‘Appreciation for locally produced food is on the rise, which means that sustainability questions are local as well. This is a good trend, as it makes it easier for us to make a difference.’ ‘Strategic help even in difficult circumstances’ The service-mindedness of lawyers is key in implementing a growth strategy. Castrén & Snellman Attorneys is a long-standing partner of Valio, and the relationship between the two is tight. ‘At Valio, we are always exploring new business opportunities, and us lawyers are tasked with assessing these opportunities. My philosophy as the General Counsel is that my door is always open. Together we can evaluate how to solve and implement new initiatives. In this job, you must be curious, broad-minded and business-oriented,’ summarises Hölttä. Hölttä’s legal team of five people is supported by experts from Castrén & Snellman. The key to successful partnership is that both parties are familiar with each other’s business operations and ways of working. ‘Castrén & Snellman knows us well, and they maintain an up-to-date overview of our situation, which I highly appreciate. It means that we are able to tackle tricky situations together quickly even in difficult circumstances.’ A joint fast reaction was needed, for example, when Valio exited the Russian market after the country launched its war of aggression on Ukraine. ‘The responsible thing was to leave quickly but in a controlled manner and by repatriating our investment as opposed to leaving an operational food production facility in the hands of a country that was waging war.’ A shared vision of sustainability Valio – Together we make life better A Finnish food company Approx. 4,600 employees Owned by 13 Finnish dairy cooperatives Finland’s most sustainable brand in the Sustainable Brand Index study Read more about sustainability at Valio Castrén & Snellman – Building sustainable success stories Forerunner of demanding legal services 300 employees Owned by its partners ‘We help our clients build sustainable success stories and achieve their sustainability goals.’ Read more about sustainability at Castrén & Snellman Shared success stories of Valio and C&S Global Brand Portfolio Management and IP Enforcement Purchase of Gold&Green’s Brand, IPR and R&D Function Joint Venture for Biogas Production with St1 Sale of Russian Operations Acquisition of Heinon Tukku Significant Growth Funding Round Competition Damages Case Defending Against Environmental Permit Challenge at the Appellate Level
Case published 4.5.2023
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.
Case published 8.12.2022