Joel Aartolahti

Associate, Member of the Finnish Bar

Services

  1. Environment, Energy & Green Transition

Contact details

I advise our clients in matters related to the environment, infrastructure and natural resources.

Before joining Castrén & Snellman I worked as a lawyer at another law firm and concentrated on real estate and construction related matters. Before my graduation I worked as a trainee in the real estate and environment team of another major law firm.

I graduated from the University of Helsinki in 2021. In addition, I studied energy and environmental law at the University of Aberdeen in Scotland for one semester.

Latest references

Downing – Acquisition of the entire share capital of Tornionlaakson Voima
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. 
Case published 27.3.2026
Merger of Oomi and Lumme Energia
We are acting as the joint legal advisor to Oomi Oy and Lumme Energia Oy in a transaction whereby Lumme Energia will merge with Oomi. As from the completion of the merger, the combined entity will be the largest electricity retail and service company in the Finnish market. In 2024, Oomi reported a turnover of EUR 373.9 million and had approximately 110 employees. Lumme Energia’s turnover for the same year was approximately EUR 314.6 million and it had approximately 50 employees. The transaction is primarily driven by the recent developments in the electricity market and the strategic goal to develop competitive products and services. Another key objective is to further enhance the customer experience, which is a shared value between the two companies. As a result of the merger, Lumme Energia’s customers will transfer to Oomi, and Lumme Energia will become one of Oomi’s shareholders. The completion of the transaction is subject to an approval by the Finnish Competition and Consumer Authority.
Case published 29.8.2025
Fortum – Acquisition of a project development portfolio for renewable power from Enersense
We are acting as a counsel to Fortum in a transaction in which Fortum is strengthening its renewable power project pipeline through the acquisition of a project development portfolio from Enersense. The debt-and-cash free purchase price is approximately EUR 9 million, with the potential for project-specific earn-outs subject to projects successfully reaching a final investment decision in the future. The transaction is subject to customary closing conditions and is expected to be completed during the first quarter of 2025. Fortum is a leading Nordic energy company with the purpose to power a world where people, businesses and nature thrive together. Fortum’s core operations comprise of efficient, CO2-free power generation as well as reliable supply of electricity and district heat to private and business customers. The company is listed on Nasdaq Helsinki. One of Fortum’s strategic targets is to develop at least 800 MW of ready-to-build onshore wind and solar projects by the end of 2026.
Case published 19.12.2024
Hanza AB – Acquisition of Leden Group
We acted as Finnish advisor to Hanza AB relating to its acquisition of all the shares in Leden Group Oy. Hanza AB is a Swedish mechanical engineering and electronics contract manufacturing company listed on the Stockholm Stock Exchange. Founded in 2008, the company has six manufacturing clusters in Sweden, Finland, Germany, Baltics, Central Europe and China and an annual turnover of approximately SEK 4.6 billion. Leden Group is a leading Finnish contract manufacturer specialising in sheet metal, machining and complex assembly. Leden Group has four production sites in Finland and one in Estonia and an annual turnover of approximately SEK 1.1 billion. 
Case published 13.12.2024
Fortum – Sale of recycling and waste business
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
Korona Invest – Sale of Innoflame
We advise Korona Invest and the other shareholders of Innoflame Oy on the sale of Innoflame to Sponsor Capital. The transaction makes Sponsor Capital the new majority owner of Innoflame. Korona Invest has been a shareholder of Innoflame since 2021 and, together with the other selling shareholders, has over the past five years supported the company’s growth, development and several strategically significant corporate transactions, through which Innoflame has strengthened its position as Finland’s leading product media company. The ownership change is intended to support Innoflame’s next phase of growth, including its ambition to build a significant European product media company with the capability to expand rapidly into new markets. The transaction is conditional to the customary closing conditions such as authority approvals. Innoflame is one of Finland’s leading product media specialists, helping its clients build a unified brand experience by offering the design, sourcing and management of product media as a single integrated service. Korona Invest is a Finnish private equity firm founded in 2006, specialising in buyout and growth investments in domestic small and medium-sized enterprises. It makes both majority and minority investments, structuring each project to suit the company’s growth strategy. 
Case published 27.8.2026
Marina Group – Acquisition of Iisiveneily and Porvoon Venekorjaamo
We advised Hopeasalmen Telakka Oy, part of Marina Group, on the acquisitions of Iisiveneily and Porvoon Venekorjaamo. The transactions form part of Marina Group’s expansion into the Finnish marina and boatyard sector, strengthening its position under the Quattro Marine brand. Following the acquisitions, Quattro Marine’s Finnish operations comprise Hopeasalmen Telakka, which operates boatyard facilities in Helsinki’s Mustikkamaa and in Tolkkinen, Porvoo, together with Iisiveneily and Porvoon Venekorjaamo. Marina Group is a Norwegian marina and boatyard consortium owned by the private equity sponsor Norvestor. It has grown rapidly through acquisitions to become the Nordic region’s largest boating services provider, having acquired 24 marinas and boatyards across Norway, Sweden and Finland within roughly a year.
Case published 24.8.2026
Neste – A EUR 250 million 10-year loan with NIB
We advised Neste as it signed a EUR 250 million 10-year loan with NIB. The loan will finance Neste’s investments related to research and development (R&D) in processing lower-quality feedstocks into high-quality renewable products; as well as the liquefied waste plastics (LWP) investment at Neste’s refinery in Porvoo, Finland. The R&D activities supported by the loan focus on the development of renewable solutions. These include, for example, expanding feedstock capabilities and technologies that enable the processing of new and lower-quality waste and residues into high-quality renewable end products. Part of the financing supports Neste’s liquefied waste plastics investment in Porvoo, related to upgrading low-quality plastic waste into high-quality feedstock at an industrial scale. The investment contributes to advancing circular economy solutions by enabling the use of hard-to-recycle plastic waste as a replacement for virgin fossil raw materials. The unit has an annual capacity to process up to 150,000 tonnes of liquefied waste plastic. Production ramp-up commenced in 2026.
Case published 19.8.2026

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