A high-voltage direct current (HVDC) electric power transmission system uses direct current (DC) for electric power transmission, in contrast with the more common alternating current (AC) transmission systems.
NorNed is a 580-kilometre (360 mi) long high-voltage direct current submarine power cable between Feda in Norway and the seaport of Eemshaven in the Netherlands, which interconnects both countries' electrical grids. It was once the longest submarine power cable in the world. Budgeted at €550 million, and completed at a cost of €600m, the NorNed cable is a bipolar HVDC link with a voltage of ±450 kV and a capacity of 700 MW. NorNed is a joint project of the Norwegian transmission system operator Statnett and its Dutch counterpart TenneT. The cable system itself and the two converter stations were produced by ABB.
TenneT is a transmission system operator in the Netherlands and in a large part of Germany.
BARD Offshore 1 is a 400 megawatt (MW) North Sea offshore wind farm with 80 BARD 5.0 turbines. Since the owner could not buy such 5MW offshore wind turbines in sufficient numbers in 2006, Dr. Bekker set up its own production of turbines. This should serve as the legacy for his children. The systems were developed by aerodyn Energiesysteme GmbH. A plant for rotor blades and nacelle assembly was built in Emden and a plant for the offshore foundations in Cuxhaven. Two turbine prototypes were set up at the Rysumer Nacken in 2007, and another prototype in Hooksiel in 2008. Construction was finished in July 2013 and the wind farm was officially inaugurated in August 2013. The wind farm is located 100 kilometres (60 mi) northwest of the isle Borkum in 40-metre (130 ft) deep water.
HVDC BorWin1 is the first HVDC facility in the world to be built for importing power from an offshore wind park to shore, and the first to use voltage source converters (VSC) in Germany. It connects the offshore wind park BARD Offshore 1 and other offshore wind farms in Germany near Borkum to the European power grid. The facility was built by ABB and has a capacity of 400 MW at a bipolar voltage of ±150 kV. HVDC BorWin1, which leads from BorWin Alpha Offshore Platform to Diele substation, consists of a 75 kilometres (47 mi) of underground and 125 kilometres (78 mi) of submarine cable.
BritNed is a 1,000 MW high-voltage direct-current (HVDC) submarine power cable between the Isle of Grain in Kent, the United Kingdom; and Maasvlakte in Rotterdam, the Netherlands.
Nordsee-Ost offshore wind farm is an offshore wind farm in operation in the eastern part of the North Sea German sector. The project was developed by RWE Innogy, a subsidiary of RWE.
The North Sea Link is a 1,400 MW high-voltage direct current submarine power cable between Norway and the United Kingdom.
HVDC DolWin1 is a high voltage direct current link built to transmit offshore wind power to the power grid of the German mainland. The project differs from most HVDC systems in that one of the two converter stations is built on a platform in the sea. Voltage-Sourced Converters are used and the total cable length is 165 km. The project was built by ABB and was handed over to its owner, TenneT, in July 2015, the fifth such project to be completed in Germany in 2015.
HVDC HelWin1 is a high voltage direct current (HVDC) link built to transmit Offshore wind power to the power grid of the German mainland. The project differs from most HVDC systems in that one of the two converter stations is built on a platform in the sea. Voltage-Sourced Converters are used and the total cable length is 130 km. The project was completed and handed over to its owner, TenneT, in February 2015.
Dogger Bank Wind Farm is a group of offshore wind farms under construction 130 to 200 kilometres off the east coast of Yorkshire, England in the North Sea. It is considered to be the world's largest offshore windfarm. It was developed by the Forewind consortium, with three phases envisioned - first phase, second phase and third phase. In 2015 the third phase was abandoned, while the first and second phases were granted consent. It was initially expected that the Dogger Bank development will consist of four offshore wind farms, each with a capacity of up to 1.2 GW, creating a combined capacity of 4.8 GW. As of 2023, a total of 277 turbines are expected to be built and produce a capacity of 3.6 GW, enough to power 6 million homes.
HVDC BorWin2 is a high voltage direct current (HVDC) link built to transmit offshore wind power to the power grid of the German mainland. The project differs from most HVDC systems in that one of the two converter stations is built on a platform in the sea. Voltage-Sourced Converters are used and the total cable length is 200 km. The project was completed by the Siemens/ Prysmian consortium and handed over to its owner, TenneT, in January 2015, becoming the first such project to be completed.
HVDC SylWin1 is a high voltage direct current (HVDC) link to transmit offshore wind power to the power grid of the German mainland. The project differs from most HVDC systems in that one of the two converter stations is built on a platform in the sea. Voltage-Sourced Converters with DC ratings of 864 MW, ±320 kV are used and the total cable length is 205 km. The project is similar to the HVDC BorWin2 project but has slightly higher power and voltage ratings. It is being built by the Siemens/ Prysmian consortium and was handed over to its owner, TenneT, in April 2015.
HVDC DolWin2 is a high voltage direct current (HVDC) link to transmit offshore wind power to the power grid of the German mainland. The project differs from most HVDC systems in that one of the two converter stations is built on a platform in the sea. Voltage-Sourced Converters with DC ratings of 900 MW, ±320 kV are used and the total cable length is 135 km. The project is similar to the HVDC DolWin1 project but has a slightly higher power rating and uses a different design of offshore platform. The platform was designed by Norwegian company Aibel and built by Drydocks World in Dubai and transported to Europe in the summer of 2014 to be fitted out at the Aibel yard in Haugesund in Norway. The platform, which is of a floating, self-installing design not previously used in an HVDC project, sailed out from Haugesund on 1 August 2015 and was installed in the North Sea ten days later.
HVDC DolWin3 is a high voltage direct current (HVDC) link to transmit Offshore wind power to the power grid of the German mainland. The project differs from most HVDC systems in that one of the two converter stations is built on a platform in the sea. Voltage-Sourced Converters with DC ratings of 900 MW, ±320 kV are used and the total cable length is 160 km.
HVDC BorWin3 is a high voltage direct current (HVDC) link under construction to transmit offshore wind power to the power grid of the German mainland. The project differs from most HVDC systems in that one of the two converter stations is built on a platform in the sea. Voltage-Sourced Converters with DC ratings of 900 MW, ±320 kV are used and the total cable length is 160 km. The project is the most recent of the German offshore HVDC projects to be awarded. It is being built by the Siemens/ Petrofac consortium with the offshore platform contract awarded to Drydocks World in Dubai. The project is expected to be handed over to its owner, TenneT, in 2019. The project started power transmission in August 2019. TenneT took control of operations in February 2020.
COBRAcable is a ±320 kV, 700 MW HVDC submarine power cable pair between Eemshaven, the Netherlands and Endrup near Esbjerg, Denmark. The cable is jointly owned by Energinet.dk and TenneT. Its purpose is to improve the European transmission grid and thus increase the amount of variable wind power in the system while improving supply reliability. Its 700 MW capacity corresponds to an annual transmission capacity of 6.1 TWh.
Kriegers Flak is a 605 MW offshore wind farm in the Baltic Sea on the Danish part of the reef of the same name. It forms part of a new 400 MW interconnector between Denmark and Germany.
Veja Mate is a German 402 MW offshore wind farm in the German Bight of the North Sea about 95 km northwest of Borkum. The wind farm consists of 67 Siemens Wind Power SWT-6.0-154 turbines, each with a 6 MW capacity.
