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Smestad-Sogn

New 420-kilovolt compact station facility and new cable interconnector.

Statnett has built a tunnel for new cable interconnectors between Smestad and Sogn in Oslo. 

The new cables will replace the current two cable interconnectors between Smestad and Sogn, owned by Elvia. The cables are from 1955 and 1977 and are nearing the end of their technical lifespan. Smestad substation was built in 1952. Capacity at both the substation and the cables must increase to provide a better supply of electricity to residents in Oslo. 

Prior to applying for a licence to build Statnett thoroughly explored two potential solutions for the cable interconnectors between Smestad and Sogn: cable in tunnel and cable in trench. We mapped buildings, infrastructure, roads and the environment, assessed emergency preparedness, risk for the surrounding areas and made economic calculations. Throughout the process, we have had meetings with local authorities and public agencies to receive their input. 

A tunnel has many advantages compared with a trench. Cables in a separate tunnel are less exposed to damage, easier to inspect and easier to maintain and repair. They provide greater flexibility, have less impact on the environment, and are generally more profitable and have a shorter installation period.  A tunnel is a secure, robust and forward-looking solution for the Oslo main grid.

Based on a comprehensive assessment, a tunnel was considered the best solution for security of supply and the surroundings. We therefore applied for a licence from the authorities to build a separate tunnel for the new cables between Smestad and Sogn.

Smestad and Sogn substation

Statnett has renewed Smestad and Sogn substations and the cable connection between Sogn and Smestad.

  • Consultation round completed

    The licence application for Smestad–Sogn and Smestad substation was submitted for consultation. At the close of the deadline, the NVE had received 45 comments from private individuals and public ag …

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  • Open office days completed

    The Greater Oslo Grid Plan project organised open office days from 13 - 25 June, but it is not too late to ask us questions.

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  • Public meetings held

    Around 100 people attended a public meeting organised by the NVE recently in connection with the application to renew the Smestad-Sogn cable interconnector and Smestad substation.

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  • Test drilling completed

    Statnett is still assessing how the electricity connection between Smestad and Sogn best can be upgraded. The assessments will clarify whether the power cables should be installed in a trench or in …

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  • Test drilling started

    Statnett has started assessing how the electricity connection between Smestad and Sogn best can be upgraded. Test drilling has now begun to examine the soil conditions.

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  • Cable interconnector assessment launched

    The electricity connections between Smestad and Sogn substations are so old that they need replacing to ensure a reliable supply of electricity to residents in Oslo in the years to come. Consequent …

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Frequently asked questions

  • Why does the Smestad-Sogn cable interconnector need to be upgraded?

    The power cables between Smestad and Sogn in Oslo are old and have limited capacity. The cables must be upgraded to ensure that people in Greater Oslo will have a reliable supply of electricity in the future. Since 1990, electricity consumption in Greater Oslo has increased by more than 30 per cent, and is expected to continue increasing in upcoming years. The capacity of the current main grid is insufficient to cover the future electricity consumption.

    There are currently two earth cables between Smestad and Sogn in Oslo. The cables, from 1955 and 1977, have reached the end of their technical lifetimes, and capacity is about to be depleted. It is urgent that we replace these cables in order to ensure reliable supply of electricity in Greater Oslo in the future.

  • Why does the Smestad substation need to be upgraded?

    The Smestad substation in Oslo is old and has limited capacity, at the same time as electricity consumption in the region is expected to increase. The station, built in 1952, has reached its expected lifetime and needs upgrades. An upgrade of the station will improve reliability of the electricity supply in Oslo.

  • What are the benefits of renewing the Smestad-Sogn cable interconnector and Smestad substation?

    The overall Greater Oslo Grid Plan consists of 30 different measures. When all measures have been completed, the grid will have capacity to transport about 60 per cent more electricity. At the same time, we can demolish around 300 kilometres of power lines. This will facilitate a more reliable electricity supply and sound climate solutions. Furthermore, it will free up areas and give a more energy-efficient power grid where less electricity is lost on its way to the consumers.

  • Why does Sogn substation need upgrading?

    Sogn substation in Oslo is old and has limited capacity. At the same time, electricity consumption in the region is expected to increase. The substation, which was built in 1949, has reached the end of its lifespan and needs upgrading. Renewing the substation will increase security of supply in Oslo.

  • What kind of solution is relevant for Sogn substation?

    We will consider a compact station facility for Sogn substation. Such a facility is more compact and requires much less space than the current air-insulated facility. By using the compact technology, it is possible to build a new substation while at the same time supplying electricity to Oslo residents from the current substation.

  • When will you submit the licence application for Sogn substation?

    Statnett is planning to apply for a licence from the Norwegian Water Resources and Energy Directorate (NVE) for Sogn substation by the end of 2016/beginning of 2017. 

  • How can people provide input?

    After Statnett has applied for a licence for Sogn substation, the NVE will submit the licence application for consultation. The NVE will conduct public meetings in connection with the licence application, and Statnett will attend these meetings.