Many of the existing lines and substations connected to the grid in Oslo and Akershus are old and needs to be renewed. Technical lifespan for lines is 70-100 years. For substations, the lifespan is 50 years.

- The grid needs to be renewed to secure supply of electricity in the Oslo region in the future, says VP corporate communications and public affair Nina Yong Kviberg.

Old grid and increased power consumption calls for a more robust electrical grid

There have been made few investments to the grid in Greater Oslo since 1990. At the same time the power consumption have increased by more than 30 percent. This has been possible because the grid was built with extra capacity. This extra capacity is almost consumed.

In 2010 the people of Oslo and Akershus used 18,7 terrawatt hours (TWh). This is 13 percent of the total usage in Norway. Statnetts mandate is to make sure that the grid can supply enough electricity when the consumption is at a maximum. We need to be able to supply energy for everyone turning up the heat at the same time during the coldest day of the year. Our job is to make sure the grid can handle the coldest day of the year.

Increased electricity dependence

The consequences of a power outage in Oslo and Akershus will be major. 1,2 million people live in the Greater Oslo area, and most of them depend on electricity for heating, cooking and getting to work. Many crucial institutions are located in this area as well.

In 2030 there could be 400 000 more people in Greater Oslo, according to Statistics Norway (SSB). That means 400 000 more people needing electricity for heating, travelling by trolleys and trains, warm water for their washing machines, showers and coffee makers. This requires a more robust grid than the one we have today.

- Statnett is building for the future. This means upgrading the grid to handle new challenges and consumption patterns. We are expecting a transition from fossil to electric heating in houses and office buildings. We are also expecting an increased electrification of transport, says Kviberg.

When Statnett starts upgrading the grid in and around Oslo, we will continue to plan as far ahead as possible. There will be many uncertainties when planning for the distant future, but we will build a grid with enough capacity to handle a comprehensive electrical future.

Increased grid capacity facilitates future consumption growth

The grid voltage is today at 300 kilovolt (kV). Statnett will now replace the existing lines and substations, so the grid can be upgraded to a higher voltage (420kV).

- With higher voltage the grid can transfer more electricity. The extra capacity allows for population growth and more consumption, says project manager Kristin Melander Vie.

The upgrade will be finished in 2030 at the earliest.

More robust

Upgrading to a higher voltage means transporting more energy through lines and substations. The upgrade will consist of both minimal expansion to total rebuilding.

- For some lines, we only need to make small changes to the high voltage towers. In other cases, we need to build new lines before demolishing the existing ones. Existing substations will be expanded or rebuilt, Vie says.

In order to upgrade existing infrastructure we need to disconnect existing lines and substations, but secure the supply of electricity at the same time. This requires planning. 

Increased capacity and fewer towers

The future grid will be able to transport about 60 percent more electricity. Meanwhile, areas with routes today could be released.

- Through modernizing the grid, we will be able to transport more electricity with fewer lines, Vie says.

It is important that everything is done in the right order. We need to build the new grid first. When this is ready, we can remove the old one. Exactly when this will happen depends on when the new grid is completed.