400 Kilovolt Network in Helsinki
We are planning a 400 kilovolt power transmission connection to Helsinki in order to meet the city’s growing electricity consumption and the requirements of the clean transition.
Background to the Construction of the 400 Kilovolt Network: Supporting the City’s Growth, Vitality, and Clean Transition
Electricity consumption in Helsinki is increasing rapidly. The principal drivers are the clean transition, which is electrifying heating and transport, and the city’s ongoing development, both of which are boosting demand.
At the same time, local electricity production is now lower than before, meaning that electricity must be transmitted from further afield. This increases the need to strengthen the grid’s capacity, ensuring that sufficient electricity is available under all circumstances.
Helsinki already has a robust and reliable electricity network, but as the city grows, major investment is required, particularly in the main grid connections. Through these investments, we will ensure that the electricity grid functions smoothly and serves our customers with minimal disruption now and in the future.
Helsinki is home to several functions and services that are vital to society, and their electricity supply must operate flawlessly at all times. Such services include healthcare, public transport, and many other critical operations. Improving security of supply is a central part of developing the electricity network. By investing in the resilience of the grid, we guarantee that both everyday services and critical functions remain operational safely and reliably, even in the event of disturbances or exceptional circumstances.
The 400 Kilovolt Voltage Level Reinforces Future Electricity Transmission
Currently, Helsinki’s main connections are based on a 110 kilovolt voltage level. To secure growing electricity use in the future, 400 kilovolt connections are also needed alongside these. Introducing the new voltage level will increase grid capacity and ensure that electricity can be transmitted smoothly to where it is most needed.
At the beginning of 2026, a change to the Electricity Market Act transferred part of the network development responsibilities to distribution system operators. As a result of the legislative amendment, local and regional 400 kilovolt networks will henceforth fall under the responsibility of the distribution system operator. In Helsinki, this means that Helen Sähköverkko Oy is responsible for developing the network from the transmission grid connection point towards the concentration of consumption.
The introduction of the new 400 kilovolt voltage level will also change the role of the existing 110 kilovolt network. In future, investments will be needed in both voltage levels to ensure that the whole system serves customers as reliably as possible.
Electricity consumption growth forecast
| Year | Actuals | Forecast |
| 1910 | 1.00 | 0.00 |
| 1915 | 5.00 | 0.00 |
| 1920 | 8.00 | 0.00 |
| 1925 | 14.00 | 0.00 |
| 1930 | 23.00 | 0.00 |
| 1935 | 25.00 | 0.00 |
| 1940 | 34.00 | 0.00 |
| 1945 | 51.00 | 0.00 |
| 1950 | 58.00 | 0.00 |
| 1955 | 105.00 | 0.00 |
| 1960 | 154.00 | 0.00 |
| 1965 | 218.00 | 0.00 |
| 1970 | 312.00 | 0.00 |
| 1975 | 375.00 | 0.00 |
| 1980 | 444.00 | 0.00 |
| 1985 | 572.00 | 0.00 |
| 1990 | 630.00 | 0.00 |
| 1995 | 647.00 | 0.00 |
| 2000 | 702.00 | 0.00 |
| 2005 | 759.00 | 0.00 |
| 2010 | 813.00 | 0.00 |
| 2015 | 766.00 | 0.00 |
| 2020 | 734.00 | 0.00 |
| 2025 | 987.00 | 0.00 |
| 2030 | 0.00 | 1460 |
| 2035 | 0.00 | 1620 |
Connection Between Sörnäinen and Vanhakaupunki
New electricity transmission structures are being planned for Helsinki
- New Cable Tunnel Between Vanhakaupunki and Sörnäinen
A cable tunnel of approximately 4.2 kilometres is being planned between Vanhakaupunki and Sörnäinen. The tunnel solution was chosen because there is not enough space for 400 kilovolt transmission lines within the current street structures.
- New 400/110 kV Substation in the Hanasaari Area
A new Sörnäinen 400/110 kilovolt substation is planned for the Hanasaari energy block area. The new substation will strengthen electricity transmission capacity and secure the area’s future energy needs.
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