Statnett has applied for two different technical solutions between Hamang substation in Bærum and Smestad substation in Oslo.  
 

- We are applying for two alternatives in prioritized order. Firstly, we apply for overhead lines. In accordance with authority policies, we applyfor cable in trench as a second priority. Both overhead lines and cable in trench are technical solutions that will secure future supply of electricity in Greater Oslo, says Siri Revelsby, Project Manager in Statnett. 

A new overhead in line costs approximately 240-320 MNOK. A cable in trench/tunnel costs approximately 1120-1370 MNOK. 

- Statnett has decided to apply for both technical solutions, to make it possible for stakeholders to benefit from cable in trench on the entire or parts of the route within the framework of the white paper on the development of the electricity grid, says Revelsby.  

In the application we have visualized the possible gains of cable in trench. These are difficult to appraise. The application process will therefore document the gains of cables versus overhead lines. Both technical solutions will for the most part use the existing route. The existing overhead line will be removed when the new line is built.  

Hamang-Bærum-Smestad consists of two routes: Hamang to Bærum substation and Bærum to Smestad substation. 
 
From Hamang to Bærum Statnett apply for overhead lines is our first priority, and cable in trench as second priority. For the route between Bærum and Smestad, Statnett apply for overhead lines from Bærum to Montebello underground substation and a cable in trench to Smestad substation as our first priority. We apply for a cable in trench from Bærum to Hagabråten and cable in tunnel from Hagabråten to Smestad as our second priority.  

- Statnett is applying to renew both routes to have a joint licensing process and implementation of the new power lines, although the route between Bærum and Smestad is less time critical, says Revelsby.  

It is possible to use a cable for parts of the route, out from one of the substations. The license process will determine whether this is an applicable option. 

A need to increase the capacity in the main grid 
The power line between Hamang, Bærum and Smestad substations is a part of the Greater Oslo Grid Plan. This is an overall plan consisting of 30 different measures to meet the future demands of supply security, urban development and climate friendly solutions. You can read more about the Greater Oslo Grid Plan on Statnett.no.  

The total consumption of electricity in Oslo and Akershus has increased by more than 30 percent since 1990. Population growth and electrification of new areas are expected to increase the consumption further. The existing main grid does not have enough capacity to handle this growth.  

- By upgrading the grid between Hamang, Bærum and Smestad, Statnett is ensuring the supply of electricity to the Greater Oslo area on both short and long term. This is an area that is depending on electric power transported from other parts of the country. To be able to do this, we need a robust main grid, says Executive Vice President Elisabeth Vike Vardheim in Statnett.  

A large part of the electricity consumption in Greater Oslo comes from heating. The main grid therefore needs to be dimensioned to so it can transport electricity to everyone who needs it on cold winter day, when consumption is at its highest.  

- In the mid 2020s, on a very cold winter day, there is a risk of electricity outage if something is wrong with the grid. From the mid 2030s this could happen even when there is nothing wrong.  In addition, the existing overhead lines are close to their technical lifespan. Therefore, we are applying to renew the interconnector on the section, says Revelsby.  

The application is now sent to the Norwegian Water Resources and Energy Directorate (NVE). They will submit the application for consultation, and all affected parties may give their comments. After the consultation period, NVE decides if further assessments should be made. It is the authorities that decide what Statnett will build.  

Questions about the licensing process can be directed to NVE.  

More information: 

Download the application in Norwegian at the bottom of the page.  

More information here. 

White paper on the development of the Norwegian electricity grid: 

The white paper on the development of the Norwegian electricity grid from 2012 says that the main grid (300 and 420 kV) is to be built as overhead lines, except: 

  • When overhead lines are technically difficult or impossible, for example in urban areas or when crossing large sea areas.
  • If the extra cost of cable on a limited part of the section is weighed up for by environmental benefits or if it provides a better overall solution when all considerations are taken into account. 

Facts: 

Cost of overhead lines: Hamang-Bærum-Smestad – estimated 240-320 MNOK.  

Cost of cable: Hamang-Bærum-Smestad – estimated 1000-1250 MNOK + 120 MNOK for renewing Bærum substation.  

Length: App. 12 km 

Pylon: design tower "Strå"..  

Start date: Depends on the application process 

Expected completion: Approximately 3-4 years after final license is given.