The Anonymous Widower

UK To Norway Sub-Sea Green Power Cable Operational

The title of this post is the same as that of this article on the BBC.

This is the first two paragraphs.

The world’s longest under-sea electricity cable, transferring green power between Norway and the UK, has begun operation.

The 450-mile (725km) cable connects Blyth in Northumberland with the Norwegian village of Kvilldal.

The BBC article is based on this press release from National Grid.

The link has been called the North Sea Link (NSL).

These are some thoughts.

What Is The Capacity Of The North Sea Link?

The National Grid press release says this.

[The link] will start with a maximum capacity of 700 megawatts (MW) and gradually increase to the link’s full capacity of 1400MW over a three-month period.

It also says this.

Once at full capacity, NSL will provide enough clean electricity to power 1.4 million homes.

It is more or less equivalent to two or three gas-fired power stations.

What Is The Operating Philosophy Of The North Sea Link?

The National Grid press release says this.

The Norwegian power generation is sourced from hydropower plants connected to large reservoirs, which can respond faster to fluctuations in demand compared to other major generation technologies. However, as the water level in reservoirs is subject to weather conditions, production varies throughout seasons and years.

When wind generation is high and electricity demand low in Britain, NSL will enable renewable power to be exported from the UK, conserving water in Norway’s reservoirs. When demand is high in Britain and there is low wind generation, hydro power can be imported from Norway, helping to ensure secure, affordable and sustainable electricity supplies for UK consumers.

It almost seems to me, that the North Sea Link is part of a massive pumped-storage system, where we can bank some of our wind-generated electricity in Norway and draw it out when we need it.

I would suspect that the rate and direction of electricity transfer is driven by a very sophisticated algorithm, that uses detailed demand and weather forecasting.

As an example, if we are generating a lot of wind power at night, any excess that the Norwegians can accept will be used to fill their reservoirs.

The Blyth Connection

This page on the North Sea Link web site, describes the location of the UK end of the North Sea Link.

These three paragraphs describe the connection.

The convertor station will be located just off Brock Lane in East Sleekburn. The site forms part of the wider Blyth Estuary Renewable Energy Zone and falls within the Cambois Zone of Economic Opportunity.

The converter station will involve construction of a series of buildings within a securely fenced compound. The buildings will be constructed with a steel frame and clad with grey insulated metal panels. Some additional outdoor electrical equipment may also be required, but most of the equipment will be indoors.

Onshore underground cables will be required to connect the subsea cables to the converter station. Underground electricity cables will then connect the converter station to a new 400kV substation at Blyth (located next to the existing substation) which will be owned and operated by National Grid Electricity Transmission PLC.

This Google Map shows the area.


  1. The light grey buildings in the North-West corner of the map are labelled as the NSL Converter Station.
  2. Underground cables appear to have been dug between the converter station and the River Blyth.
  3. Is the long silver building to the West of the triangular jetty, the 400 KV substation, where connection is made to the grid?

The cables appear to enter the river from the Southern point of the triangular jetty. Is the next stop Norway?

Britishvolt And The North Sea Link

Britishvolt are are building a factory at Blyth and this Google Map shows are to the North and East of the NSL Converter Station.

Note the light-coloured buildings of the NSL Converter Station.

I suspect there’s plenty of space to put Britishvolt’s gigafactory between the converter station and the coast.

As the gigafactory will need a lot of electricity and preferably green, I would assume this location gives Britishvolt all they need.

Where Is Kvilldal?

This Google Map shows the area of Norway between Bergen and Oslo.


  1. Bergen is in the North-West corner of the map.
  2. Oslo is at the Eastern edge of the map about a third of the way down.
  3. Kvilldal is marked by the red arrow.

This second Google Map shows  the lake to the North of Kvilldal.


  1. Suldalsvatnet is the sixth deepest lake in Norway and has a volume of 4.49 cubic kilometres.
  2. Kvilldal is at the South of the map in the middle.

This third Google Map shows Kvilldal.


  1. Suldalsvatnet is the dark area across the top of the map.
  2. The Kvilldal hydro-electric power station on the shore of the lake.
  3. Kvilldal is to the South-West of the power station.

Kvilldal doesn’t seem to be the biggest and most populous of villages. But they shouldn’t have electricity supply problems.

Kvilldal Power Station And The North Sea Link

The Wikipedia entry for Kvilldal power station gives this information.

The Kvilldal Power Station is a located in the municipality of Suldal. The facility operates at an installed capacity of 1,240 megawatts (1,660,000 hp), making it the largest power station in Norway in terms of capacity. Statnett plans to upgrade the western grid from 300 kV to 420 kV at a cost of 8 billion kr, partly to accommodate the NSN Link cable] from Kvilldal to England.

This power station is almost large enough to power the North Sea Link on its own.

The Kvilldal power station is part of the Ulla-Førre complex of power stations and lakes, which include the artificial Lake Blåsjø.

Lake Blåsjø

Lake Blåsjø would appear to be a lake designed to be the upper reservoir for a pumped-storage scheme.

  • The lake can contain 3,105,000,000 cubic metres of water at its fullest.
  • The surface is between 930 and 1055 metres above sea level.
  • It has a shoreline of about 200 kilometres.

This Google Map shows the Lake.

Note the dam at the South end of the lake.

Using Omni’s Potential Energy Calculator, it appears that the lake can hold around 8 TWh of electricity.

A rough calculation indicates that this could supply the UK with 1400 MW for over eight months.

The Wikipedia entry for Saurdal power station gives this information.

The Saurdal Power Station is a hydroelectric and pumped-storage power station located in the municipality of Suldal. The facility operates at an installed capacity of 674 megawatts (904,000 hp) (in 2015). The average energy absorbed by pumps per year is 1,189 GWh (4,280 TJ) (in 2009 to 2012). The average annual production is 1,335 GWh (4,810 TJ) (up to 2012)

This Google Map shows the area between Kvilldal and Lake Blåsjø.


  1. Kvilldal is in the North West of the map.
  2. Lake Blåsjø is in South East of the map.

This second Google Map shows the area to the South-East of Kvilldal.


  1. Kvilldal is in the North-West of the map.
  2. The Saurdal power station is tight in the South-East corner of the map.

This third Google Map shows a close-up of Saurdal power station.

Saurdal power station is no ordinary power station.

This page on the Statkraft web site, gives a brief description of the station.

The power plant was commissioned during 1985-1986 and uses water resources and the height of fall from Lake Blåsjø, Norway’s largest reservoir.

The power plant has four generating units, two of which can be reversed to pump water back up into the reservoir instead of producing electricity.

The reversible generating units can thus be used to store surplus energy in Lake Blåsjø.

Is Lake Blåsjø and all the power stations just a giant battery?

Economic Effect

The economic effect of the North Sea Link to both the UK and Norway is laid out in a section called Economic Effect in the Wikipedia entry for the North Sea Link.

Some points from the section.

  • According to analysis by the United Kingdom market regulator Ofgem, in the base case scenario the cable would contribute around £490 million to the welfare of the United Kingdom and around £330 million to the welfare of Norway.
  • This could reduce the average domestic consumer bill in the United Kingdom by around £2 per year.
  • A 2016 study expects the two cables to increase price in South Norway by 2 øre/kWh, less than other factors.

This Economic Effect section also talks of a similar cable between Norway and Germany called NorGer.

It should be noted, that whereas the UK has opportunities for wind farms in areas to the North, South, East and West of the islands, Germany doesn’t have the space in the South to build enough wind power for the area.

There is also talk elsewhere of an interconnector between Scotland and Norway called NorthConnect.

It certainly looks like Norway is positioning itself as Northern Europe’s battery, that will be charged from the country’s extensive hydropower and surplus wind energy from the UK and Germany.

Could The Engineering Be Repeated?

I mentioned NorthConnect earlier.

  • The cable will run between Peterhead in Scotland and Samnanger in Norway.
  • The HVDC cable will be approximately 665 km long.
  • The cable will be the same capacity as the North Sea Link at 1400 MW.
  • According to Wikipedia construction started in 2019.
  • The cable is planned to be operational in 2022.
  • The budget is €1.7 billion.


  1. Samnager is close to Bergen.
  2. NorthConnect is a Scandinavian company.
  3. The project is supported by the European Union, despite Scotland and Norway not being members.
  4. National Grid is not involved in the project, although, they will be providing the connection in Scotland.

The project appears to be paused at the moment, awaiting how North Sea Link and NordLink between Norway and Germany are received.

There is an English web site, where this is the mission statement on the home page.

NorthConnect will provide an electrical link between Scotland and Norway, allowing the two nations to exchange power and increase the use of renewable energy.

This sounds very much like North Sea Link 2.

And then there is Icelink.

  • This would be a 1000-1200 km link between Iceland and the UK.
  • It would have a capacity of 1200 MW.
  • National Grid are a shareholder in the venture.
  • It would be the longest interconnector in the world.

The project appears to have stalled.


I can see these three interconnectors coming together to help the UK’s electricity generation become carbon-free by 2035.






October 3, 2021 - Posted by | Computing, Energy, Energy Storage | , , , , , , , , ,


  1. Is the hardware which can cut the power at the Norwegian end a Kvilldall switch? [Sorry]

    Comment by MilesT | October 3, 2021 | Reply

  2. My Norwegian friends really do not like this development. Norway has a complex energy market and electricity prices have risen sharply in Southern Norway.

    Comment by Robin St.Clair | October 3, 2021 | Reply

    • Wikipedia has a lot to say about that under Economic Affect in North Sea Link. I was going to add my view later, as I think it’s all rather complicated.

      It could even be about getting German-funded electricity from the UK to Germany!

      Comment by AnonW | October 3, 2021 | Reply

      • A few days ago I went past a well known Nuclear Power Station in Southern England. The surveyors were at work. Not uncoincidentally, EDF’s substation link to France is offline, which makes life difficult for the UK, not that I can see any physical damage….
        Germany is corporately anti-nuclear, that is a decision that will have to be revised in the short-term.

        Comment by Robin St.Clair | October 3, 2021

  3. The Germans have a problem with nuclear. Or it could be two problems.

    The Czech Republic has signed a Memorandum of Understanding with Rolls-Royce over SMR.

    Rolls has factories and connected suppliers and associates in Germany, that could be used for specialist manufacture of parts for the SMRs.

    Comment by AnonW | October 3, 2021 | Reply

  4. […] UK To Norway Sub-Sea Green Power Cable Operational — The Anonymous Widower […]

    Pingback by UK To Norway Sub-Sea Green Power Cable Operational — The Anonymous Widower « nuclear-news | October 4, 2021 | Reply

  5. The broad subject we have to resolve is… How do you ensure a base generating load in the face of increasing levels of variable renewable energy generation. This article is highlighting the contribution that pumped storage can make and we are aware of the contribution that emergent battery technology can make. In spite of these two valuable solutions they have their pros and cons, what we need are more options. The prospects of gravity storage and air storage have been touched on but I do wonder about the feasibility of geothermal and tidal energy sources.
    I find it particularly surprising that the UK with some of the more extreme tidal ranges in the world has not made more of this opportunity.

    Comment by fammorris | October 4, 2021 | Reply

  6. Effectively, I think we can consider the North Sea Link to be a 1.4 GW power station. It is no different to two average-sized gas-fired power stations, except that it is a hydro station in Norway, backed by a massive amount of water a thousand metres up a mountain.

    The Norwegians can consider the UK as a 1.4 GW wind farm, that can help fill the reservoirs in Norway.

    Talk about a green partnership.

    We can store energy on-shore and gravity and compressed or liquified air are three ways of storing it.

    Geothermal is a big opportunity. In addition to the traditional hot rocks of which there are more opportunities than most think, there are dozens of abandoned coal mines full of warm water, that can be used as a heat source for heat pump-based district heating systems. And we mustn’t forget how in Islington, the Underground is used as a heat source for a district heating scheme.

    Tidal would be a big opportunity too, but for various pressure groups!

    Comment by AnonW | October 4, 2021 | Reply

    • Hybridisati

      Comment by fammorris | October 4, 2021 | Reply

  7. NSL is still not fully operational. First, there was a fault on the Norwegian end. Now it seems there’s a ‘converter valve issue’ at the Blyth/Cambois end, which will mean it’s running at half capacity until mid-June

    Statnett is seeking to debunk the theory that the new cables are causing high prices in Norway

    Comment by Peter Robins | April 1, 2022 | Reply

  8. Neuconnect have just awarded contracts to start construction of their privately funded 1.4GW interconnector between the Isle of Grain and Wilhelmshaven Their website gives more details of the route.

    Comment by Peter Robins | April 11, 2022 | Reply

  9. […] UK To Norway Sub-Sea Green Power Cable Operational, I discussed the North Sea Link interconnector to […]

    Pingback by Will Norwegian Pumped Storage Hydro Help Us Through The Winter? « The Anonymous Widower | October 7, 2022 | Reply

  10. NGESO have just announced that NSL has so far imported 4.6TWh and exported 1.1TWh. Not sure I can visualise a TWh.

    Comment by Peter Robins | October 20, 2022 | Reply

    • Cilla would have said it’s a lorra-lorra-lorra watts.

      Comment by AnonW | October 20, 2022 | Reply

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