Sanna-Mari Seppälä

Counsel, Environment & Natural Resources, Helsinki

Energy & Infrastructure, Environment & Natural Resources, Industrial Investments


Sanna-Mari Seppälä is a Helsinki-based Counsel specialized in energy, infrastructure, natural resources and industrial projects with a particular focus on demanding and market first projects, especially in renewable energy. She has extensive experience in advising clients on environmental and energy law as well as permitting of development projects and compliance with permits in the construction and operational phases. Sanna regularly represents clients in negotiations for energy and other industrial projects that require an in-depth understanding of both the industry, and the regulatory framework, such as renewable energy PPAs, offtake agreements and joint development agreements.

Her experience covers, among others, permitting and regulatory advice in respect of offshore wind energy projects, data center projects, electricity distribution systems as well as hydrogen and green fuel production plants, many of which have been the first of their kind in Finland.

In addition to an LLM degree from the University of Helsinki, Sanna holds an LLM degree in Energy and Natural Resources Law from the Queen Mary University of London, graduated with distinction. She has also been seconded twice to a major refining company, firstly during the preparations for a major turnaround and secondly during the implementation phase of the major turnaround.


Sanna is recognised as a Rising Star in the field of project development by IFLR1000.

This is what clients say about Sanna:

“She’s very precise and measured, hands-on, expert in her area of expertise.”
– IFLR1000 2023/2024 (33rd edition)

“Sanna was very ambitious and worked very hard on the agreements for which she was responsible (which was a majority of the agreements in the transaction). She had a very good knowledge and understanding of the complex key agreements and could come up with appropriate solutions and counterarguments as regards the counterparty’s mark-ups.”
– IFLR1000 2023/2024 (33rd edition)


Roschier, Counsel (2023–)
Castrén & Snellman, Associate (2016–2017), Senior Associate (2017–2020), Counsel (2020–2023)
Bergmann, Associate (2012–2015), Senior Associate (2015–2016)


Member of the Finnish Bar Association
Member of the Finnish Society for Environmental Law


Queen Mary University of London, LL.M. in Energy and Natural Resources Law (2016)
University of Helsinki, LL.M. (2012)


English, Finnish

Very precise and measured, hands-on, expert in her area of expertise.