Exploring Helsinki’s underground energy security supply

“It’s like a hidden city beneath the city” says the CSO, Helen & CEO, Helsinki Energy Tunnels, Mats Fagerström. Helsinki’s extensive underground network ensures energy security by providing resilience against potential disruptions. On 5 March 2025, NIB and Denmark’s Minister for Resilience and Preparedness, Torsten Schack Pedersen, venture beneath the surface to visit Helen, one of Finland’s largest energy companies. 

Here, vast underground tunnels wind below Helsinki’s daily city life, keeping the city alive and connected. Together, they form the city’s lifeline, delivering cooling, heating, and electricity to its residents. These 60 kilometres of urban infrastructure are crucial, yet few people know about them.

NIB and the Danish Minister visit one of Helen’s district cooling facilities, hidden in a rock cavern 50 metres underground in Helsinki’s Pasila neighbourhood. With an emphasis on security of supply, NIB is financing the construction of a similar cooling energy storage facility located beneath Esplanadi, the urban park in downtown Helsinki.

As we drive in the tunnel to Pasila, we see pipes on the walls. We learn that they are part of the district heating pipeline in Helsinki which totals almost 1,600 kilometres. One pipe is bringing the hot water to the buildings, while the other pipe returns the water that has released its thermal energy.

The visit is hosted by Helen, a long-standing client of NIB. The loans have supported the green transition and energy security – two key priorities for NIB. In total since 2009 this corresponds to four loan agreements with Helen, amounting to EUR 210 million. The latest loan to Helen is EUR 150 million, and it is a sustainability-linked loan. This was signed in 2022 to reduce carbon intensity and the absolute GHG emissions from Helen’s operations.

Resilience is an important consideration for NIB when financing critical functions that ensure the safe operation of society. Being prepared for potential emergencies and disruptions is an essential component of crisis management.

“It was a great inspiration to visit Helen Oy and learn about the supply chains in Finland. We are facing new and complex threats. European countries already see intensified hybrid activities. Therefore, it is important that we continue to increase our focus on the protection of our critical infrastructure. And to improve coordination between the Nordic countries and within NATO and the EU,” says the Danish Minister for Resilience and Preparedness, Torsten Schack Pedersen.

The visit highlights the importance of having a resilient infrastructure that is well-prepared in case of outside impact on the energy supply.

“It’s like a hidden city beneath the city, an intricate network working silently to ensure that power flows uninterrupted, even in times of crisis,” says the CSO, Helen & CEO, Helsinki Energy Tunnels, Mats Fagerström. “Together we build a stronger society, resilience planning and training are key factors for success”.

With a new strategy to become carbon-neutral by 2030 and phase out combustion-based energy production by 2040, Helen is investing in carbon-neutral energy production through renewables such as solar and wind. This strategy aligns with the strategic goals of the City of Helsinki.

“We are proud to support Helen’s district heating and cooling system, which safeguards the vital energy supply for the city of Helsinki. It is fascinating and fruitful to see Helen’s underground infrastructure and to visit the lesser-known side of the city,” says Heikki Cantell, NIB General Counsel & Secretary General.