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Upgrading the transmission grid to Oslo

In the years ahead, more and more people will move to the Oslo region. This means that the Greater Oslo power grid must be upgraded.

The objective of the Greater Oslo Grid Plan is to determine what the Oslo and Akershus main grid will look like in the future. The project will ensure that the main grid in Oslo and Akershus is upgraded to secure a reliable supply of electricity to the capital region in the period leading up to 2050. The main grid in Oslo and surrounding areas is old, and must be upgraded and reinforced to meet future requirements for security of supply, urban development and environmental solutions.

“The current facilities are old. Several of them will exceed their projected lifespan in the next few years. There is a great need for replacements due to age as well as wear and tear. Even if consumption does not increase, it will be necessary to upgrade the grid at some point, because components will eventually fail. Upgrading the grid is the only solution,” says Project Manager Kyrre Nordhagen of Statnett.

Projected population growth and new consumption, such as electric cars and heating pumps to replace oil heating, indicate that our electricity consumption will increase in the future.

Kyrre Nordhagen, Project Manager in Statnett

Increased capacity required

Society has become much more dependent on electricity in recent years. Electricity consumption in Greater Oslo has increased by 30 per cent since 1990, without any major upgrades of the main grid.

“Projected population growth and new consumption, such as electric cars and heating pumps to replace oil heating, indicate that our electricity consumption will increase in the future. The grid must be refurbished and upgraded to meet future requirements for a reliable supply of electricity, urban planning and climate solutions,” says Nordhagen.

Analyses have shown that energy efficiency measures and local generation are not enough.

“Energy efficiency measures and new building standards will not stem the growth in consumption. Such measures will affect how soon we need to reinforce the grid, but not obviate the need entirely. Most of the electricity consumption in Oslo and Akershus is supplied via the main grid, as local power production is very limited. Consequently, a satisfactory main grid is essential for the region.”

Fewer power lines and pylons

According to Nordhagen, upgrading the main grid in the Oslo region will have many positive effects. It will free up areas for other purposes, reduce the number of pylons in the forests around Oslo as well as near residential areas. Moreover, it will have a positive impact on the climate and reduce local pollution.

“And, people can be sure they will have a reliable supply of electricity in the future. It’s all connected however. If we are to reap the benefits of the project, we must reinforce the grid in the entire area to be able to free up other areas,” Nordhagen says.

According to Nordhagen, there are currently approx. 1000 kilometres of power lines in the Greater Oslo area. Of these, 300 kilometres will be upgraded, 300 kilometres will be demolished and the rest of the power lines will remain as they are today.

“Freeing up areas is important to many people. We have received input from several hundred stakeholders who believe it is important for the development of urban areas and recreational areas.”

New 420 kV interconnectors will increase capacity significantly compared with the old 300 kV interconnectors. The main reason is that Statnett will be able to reduce the number of interconnectors in Greater Oslo after the upgrades. Upgrading the voltage on existing power lines from 300 kV to 420 kV will increase the transmission capacity by about 40 per cent. Furthermore, magnetic fields will be reduced and transmission losses halved. The latter will have a very positive environmental impact.

“Current transmission losses equal an annual electricity consumption of approximately 10 000 flats – the same as a small town!”

Robust profitability

Upgrading the current Greater Oslo grid is socio-economically profitable. Statnett’s best estimate is investments of NOK 1 billion each year over a period of at least 15 years.

“The size, complexity and duration of the project indicate that there is considerable uncertainty associated with the investment costs. There will always be some uncertainty associated with cost estimates so far ahead in time,” says Nordhagen.

He thinks the biggest uncertainty drivers in term of investment scope are the price of goods and services in the future, and the extent of cabling in central areas. The costs of not investing are considered much higher than investing. Consequently, the project is considered profitable.

“This solution has robust profitability, despite the uncertainty inherent in the investment costs and benefit calculations. The reason for this is that the cost to society of insufficient grid capacity is considered to be substantial, compared with the cost of investing,” Nordhagen says.

Project Manager Kyrre Nordhagen of Statnett has no doubt that measures must be taken to meet future requirements for a reliable supply of electricity, urban development and climate solutions.

Positive to the plan

The Greater Oslo Grid Plan is the first project in the energy sector subject to the new concept choice assessment (KVU) scheme.

The purpose of the assessment is to establish a solid foundation for the future development of the Greater Oslo main grid by conducting a thorough analysis, external quality assurance and consultation and consideration by the Ministry of Petroleum and Energy.

The concept choice assessment describes the need and alternative solutions for securing the electricity supply to the Oslo region. It also outlines the overall solution, i.e. voltage upgrades. In addition, it shows that the project is socio-economically profitable.

The assessment has also been subject to external quality assurance by Det Norske Veritas. DNV found the need and overall results satisfactory.

The Ministry of Petroleum and Energy has submitted the KVU for external consultation, where all stakeholders had a chance to have their say. So far, the consultative comments have shown that no one has disputed the necessity of renewing and reinforcing the Greater Oslo grid. On the contrary, several stakeholders have stated that they are positive to the analysis and the process.

“We are very pleased with the process Statnett has implemented in this case,” says the Outdoor Recreation Board of Oslo in one of the submissions to the KVU, which are now being considered by the Ministry of Petroleum and Energy. 

Text: Inger Lise Welhaven Photo: Statnett

The most important measure to increase capacity in the main grid towards Greater Oslo is to upgrade the voltage from 300 kV to 420 kV. This will free up areas and reduce the number of pylons in the forest surrounding Oslo. The illustration below/above is from Sognsvann Lake in Oslo and shows how a new power line can replace the existing lines and thus free up valuable areas.

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