NorNed
NorNed is the name of a 580 km long high voltage direct current transmission line (HVDC ) for coupling the Norwegian and the Dutch electricity grid and used for the exchange of electrical energy. The line carries as submarine cables Feda in Norway by the North Sea to Eemshaven in the north of the Netherlands.
It opened on 6 May 2008 on the operation, on 11 September 2008, she officially by the Dutch Minister Maria van de Hoeven ( "Minister van Economische Zaken " ) was opened.
The line is 580 km long and is operated as a bipolar HVDC with a nominal DC voltage of ± 450 kV. The electrical energy can be transmitted in both directions:
Most Norwegian storage power plants are today (2011 ) is designed as a pumped storage power plants, with the electrical in sufficient available energy, water is pumped to the upper level, while at times when electrical power is not sufficiently available, this by running the water by means of generators can be recovered again.
Planning and construction
On January 19, 2004, the Dutch grid operator TenneT and Statnett, the Norwegian gave together announced its intention to relocate a high voltage cable across the North Sea to invest a combined 600 million euros and to take it into operation in 2008 ( which it did ). The cable should allow the import of electricity from Norway and expand the connection between the Scandinavian and Western European energy markets.
The construction of the cable had been agreed in a 1991 agreement in principle between the Dutch (SEP composite of the Dutch electricity producers ) and the Noorse Statkraft. At the resolution of the SEP, the privatization of the electricity sector and the low energy prices, the project was interrupted in the meantime.
The Energy Regulation, part of the Dutch Competition Authority, approved the plans on 23 December 2004, the NorNed cable. The first sections were laid in the spring of 2006, construction was completed in April 2008. On 5 May 2008, the first capacity auction was held, on May 6 began commercial use.
The laying of the cable was made in sections by a cable ship. The cable was either using a special remote-controlled digging machine in the seabed or filled with sand after installation.
Technology
The 580 km long cable runs from the Eemshaven in the Netherlands on the bottom of the North Sea into the Norwegian Feda, community Kvinesdal. 420 km of the cable line running in shallow waters (up to 50 m) and 160 km at a depth of up to 409 m. 270 km of the cable are duplicated, 310 km one way. The simple embodiment weighs about 37.5 kg / m, a double 85 kg / m. The total weight of the cable is to the 47,000 tonnes.
The compound is prepared by high-voltage direct current transmission (HVDC). The three-phase alternating current is usually used in overhead lines on the land can not be transmitted via submarine cables over long distances, because the reactive power requirement of submarine cables is too large. The submarine cable is designed as a bipolar lead two wires and can transmit a maximum active power of 700 MW. The efficiency of the transmission path is specified at 600 MW (without converter stations ) with 96.3 %.
To converter stations are located at both ends of the cable with power converters that rectify the three-phase alternating current of national networks, as well as inverters, which convert the direct current into three-phase alternating current, which is fed into the national networks. These are made on both sides of each 2 × 120 thyristors in series with three spare thyristors, so that the failure can be bridged up to three thyristors without interruption until the next service.
In contrast to the technique of monopolar high voltage direct current transmission, as in the Baltic Cable, applicable for the bipolar NorNed transfer the problem of operating -current-carrying electrode under one pole of HVDC. The advantage is to prevent the electrolysis of the seawater in the area of large-area electrodes which are used as earth electrodes. This advantage is paid for you, however, by the disadvantage of having to move two instead of just one high-voltage cable.
In the Eemshaven converter hall houses all components of the system including converter transformers, harmonic filters with 432 MVAr and a gas-insulated switchgear for 400 kV grid. In Feda is just the converter in a hall of harmonic filters with 485 MVAr, transformers and switchgear for 300 kV power grid are placed outdoors. The converter transformers exist as for larger HVDC installations common to both sides of three separate single-phase transformers.
Economic Aspects
The entire cost of the NorNed cable amounted to approximately 600 million euros. After four months of operation, the cable has earned an income of about 70 million euros, which represents almost 12 % of the construction costs. In the business case for NorNed the annual yield was estimated at 64 million euros. By the beginning of September 2008 a total of 1.8 million megawatt hours were transported by the cable, 1.7 million megawatt hours of Norway to the Netherlands and 0.1 million megawatt hours from the Netherlands to Norway.
In May 2012, it was reported that with the cable since commissioning a turnover of over 285 million euros was made. Since March 2012, it is possible via Exchange handle the electricity trading over the cable.
Similar cables are already
- Between Denmark and Sweden ( conti- Skan )
- Between Norway and Denmark (Cross - Skagerrak ) and
- The Netherlands and the UK ( BritNed cable).