Smestad-Sogn

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

Statnett is currently building a tunnel for new cable interconnectors between Smestad and Sogn in Oslo. We got a licence to build the tunnel in 2017, and started the work by the end of that year. 

The new cables will replace the current two cable interconnectors between Smestad and Sogn, owned by Hafslund. 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 have therefore applied for a licence from the authorities to build a separate tunnel for the new cables between Smestad and Sogn. 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.

Smestad substation

Today's station is from 1952. It has reach its technical lifespan and needs an upgrade to be able to provide Oslo with electricity in the future. Statnett has explored several solutions and consider a compact station (SF6) to be the best solution. Smestad substation is the biggest station in Norway for general consumption. Statnett has been granted a licence to renew Smestad substation and the cable connection between Sogn and Smestad.

Sogn substation

Today's station is from 1949, is getting close to expected technical lifespan and needs renewal. Statnett has started exploring how this renewal can be done. We will map buildings, infrastructure, roads and the environment, assessed emergency preparedness, risk for the surrounding areas and made economic calculations. Throughout the process, we will have meetings with local authorities and public agencies to receive their input.

This project is part of The Greater Oslo Grid Plan ensuring a reliable supply of electricity to Oslo and Akershus in the years to come. Click here to read more about the grid plan.