ROVworld Subsea Information

Longest subsea high-voltage cable in the world opened
Date: Friday, September 26, 2008 @ 12:00:00 EDT

Longest subsea high-voltage cable in the world openedThe world's longest subsea high-voltage cable was officially opened by the Dutch Minister of Economic Affairs, Maria van der Hoeven.

NorNed is a cooperation of TenneT, the Dutch grid manager and the Norwegian colleague Statnett. Through the connection with a length of 580 kilometres, Statnett and TenneT transport electricity from Norway to The Netherland and vice versa. NorNed provides an important contribution to a reliable power supply in both countries and to a strong European Electricity market. Statnett and TenneT celebrate the official opening of the NorNed cable in Norway and the Netherlands at the exact same time in both countries. Mel Kroon, CEO TenneT, also announced the study related to the new cable between Denmark and the Netherlands, the COBRA CABLE.

Developments NorNed cable

The operation of the NorNed cable started on the 6th of May last. With an availability of nearly 100 percent, the subsea power link between the Netherlands and Norway made a promising start. In the first four months in which the cable was operational, an extreme high return of EUR 70 million was realised. This return exceeded all expectations: in the business case formulated for the NorNed cable, an annual return of EUR 64 million was forecasted. The return will be used for new investments concerning improvement of the Dutch grid.

Since the commencement of the operation of the NorNed cable on the 6th of May last, the connection has more than met the expectations the grid managers TenneT and the Norwegian Statnett initially assumed when starting this ambitious project. Up to today, a total of 1.8 million megawatt hours has been supplied by means of this cable. In total 1.7 million megawatt hours of Norwegian hydro power was brought to the Netherlands, and a total of 0.1 million megawatt hours was exported by the Netherlands.

In the last four months the transport capacity of the cable for import was auctioned at an average price of EUR 39.29 per MW, and for export at an average price of EUR 1.42. "The NorNed cable provides a significant number of advantages, for producers and consumers alike. Thanks to NorNed, the international trade will increase which will result in more stable prices for electricity in North-western Europe. The NorNed cable represents an important physical link on the road to one single, strong European power supply market," explained TenneT CEO Mel Kroon.

Minister Maria van de Hoeven of the Ministry of Economic Affairs on the NorNed project: "I have no doubt that further steps towards market coupling will be made in the near future, benefiting all parties concerned. Most importantly, you have shown international cooperation to be the key to safeguarding security of supply, raising flexibility and maintaining affordability. Last but definitely not least, NorNed also raises the profile of Norwegian hydraulic power, helping us to 'go green'."

Facts and figures

The cable connects the high-voltage direct current (HVDC) converter stations in Eemshaven and Feda. The converter stations convert alternating current into direct current and vice versa. The size of the stations equals the size of approximately two soccer pitches. The total weight of the cable is around 47,000 tonnes and the cable is installed in eight (8) sections. The project was completed within a period of ten (10 years, of which the last three (3) years were used for the actual installation of the cable and the construction of the corresponding converter stations.

• Cable length 580 kilometres
• 420 kilometres of cable in shallow waters (up to a depth of 50 metres)
• 160 kilometres of cable at a depth up to a maximum of 410 metres
• Total weight of the cable 47,000 tonnes
• 9,000 tonnes of copper and 12,000 tonnes of led were used for the cable (580 km)
• Maximum voltage on the cable + 450 kV (kilovolt) and -450 kV
• Cable capacity 700 MW
• 24 permits in four (4) different countries
• Total project costs EUR 600 million
• 700 MW is good for half electricity of Amsterdam

Study related to a cable between Denmark and the Netherlands

During the official opening of the NorNed cable, Mel Kroon, TenneT Director announced the upcoming study for a new cable connection. National grid managers TenneT and Energinet will be evaluating the feasibility of a direct current connection between Denmark and the Netherlands. This cable - which will be name the COBRA CABLE - could contribute to increased supply reliability and stability of both electricity markets, which are actually quite different from one another. Furthermore, this interconnector fits the development of the North-western European market perfectly well.

This article comes from ROVworld Subsea Information

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