NorNed
NorNed is the name of a 580 km long high-voltage direct current transmission line (HVDC) for coupling the Norwegian and Dutch power grids and for the exchange of electrical energy . The line runs as a submarine cable from Feda in Norway through the North Sea to Eemshaven in the north of the Netherlands.
The plant went into operation on May 6, 2008, and was officially opened on September 11, 2008 by the Dutch Minister Maria van der Hoeven ("Minister van Economische Zaken"). The line is 580 km long and is operated as a bipolar HVDC transmission with a nominal DC voltage of ± 450 kV . The electrical energy can be transmitted in both directions:
Norway has around 1250 hydropower plants, the vast majority of which are storage power plants without a pumping function .
Planning and construction
On January 19, 2004, the Dutch network operator TenneT and the Norwegian Statnett jointly announced that they wanted to lay a high-voltage cable through the North Sea , to invest a total of 600 million euros and to put it into operation in 2008 (which was also successful). The cable should enable the import of electricity from Norway and expand the connection between the Scandinavian and Western European energy markets.
The construction of the cable was agreed in 1991 in a basic agreement between the Dutch SEP (Association of Dutch Electricity Generators ) and Noorse Statkraft . However, due to the dissolution of the SEP, the privatization of the electricity sector and the low energy prices, the project was temporarily interrupted.
The Energiekamer , part of the Dutch Cartel Office , approved the plans for the NorNed cable on December 23, 2004. The first sections were laid in spring 2006 and construction was completed in April 2008. On May 5, 2008 the first capacity auction took place , commercial use began on May 6th.
The cable was laid in sections using a cable layer . The cable was either sunk into the sea floor with the help of a special remote-controlled excavation machine or, after laying, it was filled in with sand.
technology
The 580 km long cable runs from Eemshaven in the Netherlands across the bottom of the North Sea to Feda in the Norwegian municipality of Kvinesdal. 420 km of the cable route run in shallow water (up to 50 m) and 160 km at a depth of up to 409 m. 270 km of the cable are duplicated, 310 km single. The simple version weighs about 37.5 kg / m, the double 85 kg / m. The total weight of the cable is around 47,000 tons.
The connection is established by high-voltage direct current transmission (HVDC). The three-phase alternating current usually used for overhead lines on land cannot be transmitted via submarine cables over long distances because the reactive power requirement of submarine cables is too great. The submarine cable is designed as a bipolar line with two wires and can transmit a maximum active power of 700 MW . The efficiency of the transmission line is given as 96.3% at 600 MW (without converter stations).
At both ends of the cable there are converter stations with converters that rectify the three-phase alternating current of the national grids, as well as with inverters that convert the direct current into three-phase alternating current, which is fed into the national grids. These consist of 2 × 120 thyristors each in series with three reserve thyristors on both sides , so that the failure of up to three thyristors can be bridged without interrupting operation until the next service.
In contrast to the technology of monopolar high-voltage direct current transmission, such as with the Baltic Cable , the bipolar NorNed transmission eliminates the problem of the earth electrode carrying the operating current of a pole of the HVDC transmission . The advantage is the avoidance of the electrolysis of the sea water in the area of the large-area electrodes that are used as earth electrodes. This advantage is bought at the price of the disadvantage of having to lay two high-voltage cables instead of just one.
In Eemshaven, the converter hall houses all the components of the system including converter transformers , harmonic filters with 432 MVAr and a gas-insulated switchgear for the 400 kV network. In Feda only the converter is in a hall, the harmonic filter with 485 MVAr, the transformers and the switchgear for the 300 kV power grid are set up outdoors. As is usual with larger HVDC systems, the converter transformers consist of three single-phase transformers on both sides.
economic aspects
The total cost of the NorNed cable was around 600 million euros. After four months of operation, the cable brought in a revenue of around 70 million euros, which corresponds to almost 12% of the construction costs. In the profitability calculation for NorNed, the annual income was estimated at 64 million euros. By the beginning of September 2008, a total of 1.8 million megawatt hours had passed through the cable, 1.7 million megawatt hours from Norway to the Netherlands and 0.1 million megawatt hours from the Netherlands to Norway.
In May 2012 it was reported that the cable has had a turnover of over 285 million euros since it was put into operation. Since March 2012 it has been possible to conduct electricity trading over the cable on the exchange.
Comparable cables are already available
- between Denmark and Sweden ( Konti-Skan ),
- between Norway and Denmark ( Cross-Skagerrak ) and
- the Netherlands and Great Britain ( BritNed cable).
Web links
- Statnett information page (Norwegian)
- TenneT information page (Dutch)
- ABB information page
- Representation in Openstreetmap
Individual evidence
- ↑ renewablesb2b.com: "In years with normal rainfall, the approximately 1250 Norwegian hydropower plants produce an average of 126.6 TWh per year (2000–2010).", Accessed on May 1, 2014
- ^ A b Jan-Erik Skog, Kees Koreman, Bo Pääjärvi, Thomas Worzyk, Thomas Andersröd: The NorNed HVDC Cable Link. A Power Transmission Highway Between Norway And The Netherlands (PDF; 504 kB)
- ↑ TenneT: NorNed cable yields positive results, May 18, 2012 ( Memento of the original from March 20, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
