Siemens has received another order from the German-Dutch grid operator, TenneT TSO, for a grid connection for offshore wind power plants in the German waters of the North Sea.
The company will supply the entire technology for efficient direct-current transmission for the “DolWin6” grid connection.
The Spanish partner, Dragados Offshore is responsible for construction and offshore installation of the associated platform.
The French supplier Nexans will supply the direct-current cables. TenneT tendered the supply and laying of the cables separately, and these services are therefore not part of Siemens’ scope of supply.
The order placed with Siemens is said to be valued in high three-digit millions euros range. After it is completed, DolWin6 will be able to transmit enough electricity to supply just under one million German homes. Commercial commissioning is scheduled for 2023.
“DolWin6 marks a new milestone for the success of the energy transition. We are very pleased with the new order from TenneT for an offshore grid connection in the German waters of the North Sea,” said Ralf Christian, CEO of Siemens’ Energy Management Division. “This makes Siemens the technology partner in six out of ten DC projects. After BorWin3 and DolWin6 are commissioned, approximately 4.7 gigawatts of electrical power will be converted and transmitted to shore using Siemens technology alone. This is enough to supply just under five million homes.”
Siemens will supply the entire technology for efficient high-voltage direct-current transmission (HVDC) and will use DC CS direct-current compact switchgear for the first time. The new gas-insulated switchgear for 320 kilovolts (kV) requires as much as 95 percent less space compared to the current air-insulated solutions. If they are used on an offshore platform, the size of the platform can thus be reduced by approximately 10 percent. As a result, Siemens is significantly helping to lower the cost of grid connections for offshore wind farms and thus to the cost parity of offshore wind energy in general. The switchgear is manufactured in Siemens’ switchgear factory in Berlin. Other components, such as HVDC transformers and converters for converting current, are produced in Siemens’ factories in Nuremberg. The offshore platform is being built by our partner Dragados in Cadiz, Spain, and will then be transported to its installation site. Siemens will be responsible for complete construction of the HVDC onshore station in Emden, East Frisia, where the company already built the onshore converter for the BorWin3 direct-current connection earlier this year.
The DolWin6 grid connection, which is around 90 kilometers in length, can connect multiple offshore wind turbines to the mainland. A number of offshore wind farms are competing for a connection to DolWin6 in an auction held by the German Gederay Network Agency. The Gode Wind 3 project has already been awarded a contract, and additional offshore wind warms will bid on the coveted grid connection in the next round of the auction. The 155 kV alternating current supplied by the wind turbines will be converted into 320 kV direct current on the DolWin6 offshore platform and transported to Hilgenriedersiel on the mainland via a 45-kilometer subsea cable. On the ocean, the cable will pass underneath the island of Norderney by means of horizontal bore holes. Once on land, the electricity will be transported by another 45-kilometer underground cable to Emden, East Frisia, where Siemens is building another converter station for converting the direct current back into three-phase current and feeding it into the high voltage grid.