Construction of a main grid cable connection in Helsinki to begin this spring

Construction of a new underground main grid cable connection in Helsinki will begin this spring. The project, run jointly by the City of Helsinki, Helen Electricity Network and Fingrid, will respond to growing electricity consumption in the Helsinki Metropolitan Area and promote the green transition. Construction began on the connection from Vaarala in Vantaa to Viikki in Helsinki in December with the clearing of trees from the cable route and worksite areas. The project is proceeding on schedule and is due for completion in 2026.   

In 2023, the City of Helsinki, Helen Electricity Network and Fingrid signed a partnership agreement to build a 400-kilovolt electricity transmission connection in Helsinki. The National Land Survey of Finland has issued an expropriation permit decision for the cable route. The cable, construction of the cable route, and substation procurement processes progressed in autumn 2023. 

“The project has proceeded on schedule and within the budget and in a good spirit of cooperation between the parties, authorities and stakeholders,” says Risto Ryynänen, Project Director at Fingrid.    

The largest contractors and suppliers are Hitachi Energy Finland Oy for substations, Tamini Trasformatori S.r.l. (an Italian company) for power transformers, Hyosung Heavy Industries Corporation (a South Korean company) for 400-kilovolt reactors, GRK Finland Ltd and Lännen Alituspalvelu Oy for construction of the cable route, and Demirer Kablo (a Turkish company) for 400-kilovolt cables. 

In addition, Architecture Office Olla Ltd and A-Insinöörit Suunnittelu Oy are responsible for the construction design of the Vanhakaupunki and Länsisalmi substations. Ramboll Finland Ltd will continue as the building consultant and designer of the cable route. 

The 400-kilovolt cable connection is expected to be completed in 2026. When completed, it will run from the Länsisalmi substation in Vantaa to the new Vanhakaupunki substation in the energy block in Viikinranta, Helsinki.  

The green transition is increasing the need for electricity transmission. The cable connection responds to growing electricity consumption.  

“Investments in the electricity grid are essential enablers of the green transition. This is an important project for Helen Electricity Network, as it will allow us to connect new customers to our network. Our Viikinmäki substation project will pave the way for connecting to Fingrid’s 400-kilovolt substation in Vanhakaupunki in 2026,” says Markku Hyvärinen, Director of Business Development at Helen Electricity Network.   

The new cable connection will also enable alterations to the electricity network for the construction of the Western Boulevard City, a project on the other side of Helsinki, around the Vihdintie and Huopalahdentie roads. Once the network is reinforced, the high-voltage 110-kilovolt overhead lines near Vihdintie and Huopalahdentie can be moved underground. This will free up land for infill construction. 

“The underground cable we are building now is mainly located under green areas and in the street area of Viikinranta, where new buildings are planned. From the City of Helsinki’s perspective, the project is important for the green energy transition and the development of the urban structure,” says Pekka Tirkkonen, Specialist in the Helsinki Urban Environment Division. 

Further information: 

Fingrid Oyj 
Risto Ryynänen, Project Director 
tel. +358 40 519 5093 
risto.ryynanen@fingrid.fi 

Helen Electricity Network Ltd 
Markku Hyvärinen, Director of Business Development 
tel. +358 50 559 1685 
markku.hyvarinen@helen.fi 

City of Helsinki, Urban Environment Division 
Pekka Tirkkonen, Specialist 
tel. +358 9 310 36637 
pekka.tirkkonen@hel.fi 

See also: 

Press release, 29 May 2023: Helsinki cable project enters implementation phase 

Press release, 21 December 2022: Fingrid confirms its investment decision in the Helsinki metropolitan area – cable link to provide more electricity as consumption rises 

Press release, 11 April 2022: Preliminary route selected for a 400-kilovolt cable to be built in Helsinki 

Project website: www.fingrid.fi/helsingin-kaapeli