Testing will initially last until the beginning of July, with a break over the summer. Testing will resume in mid-August and continue until the end of September. Once the test period has been completed, the interconnector will be ready for three months of trial operation, where all market systems should be operational. Trial operation is scheduled to start in October.


This summer’s test period will include tests of all IT and market systems. “We must ensure that the communication works at all levels, from the power trading exchange and all the way down to the converter stations. The right messages must reach their destination, and they must trigger the right responses,” says Statnett’s project manager for the interconnector's trading solution, Bjørn Harald Bakken. He emphasises that testing during this period will focus on technical installations and IT solutions, and that testing requirements rather than market signals that will determine how much power is transferred in which direction. This corresponds to the test period we had on the NordLink cable between Norway and Germany last autumn.

Capacity for the power market from October

Once the test period has been completed, all market systems should be in operation, and North Sea Link (NSL) should be ready for trial operation. “Then, Statnett and National Grid will offer capacity to the market based on normal procedures, but the interconnector will remain in a trial period for three months,” Bakken says. 

Summer testing procedures

During the test period, there will be electricity transmissions from Tuesday to Friday during the day. Most of the time, the transmission will be lower than 100 MW, but some tests will require higher power, provided the conditions in the UK and Norwegian grids allow.

  • 15 June – early July: Transmission of up to 700 MW in both directions.
  • Mid-July – mid-August: High voltage testing of the cable. No electricity transmissions.
  • Mid-August – end of September: Transmission of up to 1,400 MW in both directions.

Statnett and National Grid will trade the power transmitted in the ordinary power market on each side of the cable. The day before each test day, Statnett will publish information about the planned trade for each hour on the NUCS platform. National Grid will publish the same information on Elexon.


Read more about NSL here