Start of construction for DolWin gamma offshore converter platform

The construction works of the DolWin gamma offshore converter platform started today, 9 October, at Nordic Yards in Warnemünde. This was marked by the traditional first steel cut, which took place at the Warnemünde site in the presence of representatives of the contractor Alstom and customer TenneT.

As general contractor, Alstom had placed an order with Nordic Yards in February 2013 for the construction of the offshore platform for the DolWin3 project run by the Dutch transmission system operator TenneT. Equipped with Alstom´s low-loss, high-voltage direct current (HVDC) technology, the converter platform ensures that the power generated in offshore wind farms is transmitted to the mainland. Located in the south western part of the North Sea, DolWin gamma will convert 900 MW of electricity from AC to DC and transmit it to the Dörpen onshore converter station via sea and land cable. In Dörpen the power will be converted back to AC, fed into TenneT’s onshore transmission grid and supplied to the end users.

DolWin gamma is already the fourth HVDC platform to be constructed by Nordic Yards. The shipyard group is also for the first time responsible for transportation and installation in addition to basic and detailed planning. “We are looking forward to advancing Germany’s energy transition together with our customers,” says Nordic General Manager Fred Wegener. “The DolWin gamma project is more complex and demanding than our three previous platform projects. We are looking forward to a continued successful partnership with TenneT and Alstom.”

“The converter platform will be the core of one of a total of twelve connections for offshore wind farms in the North Sea. Together, they will help TenneT to develop around 7.1 Gigawatts of connection capacity by 2019 and to live up to its role as the largest investor in the energy transition,” says Wilfried Breuer, Managing Director Offshore of TenneT TSO.

“As general contractor in this project, Alstom – together with our partners – will contribute to the successful and efficient grid integration of offshore wind power. Today’s on-schedule steel cut shows that we have found a reliable partner in Nordic Yards for the implementation of this major project,” said Gerhard Seyrling, Vice President Alstom Grid, Region Central & Eastern Europe and Russia.

At its three sites, Nordic Yards will construct an optimised design of both the topside and the substructure of the platform. The Alstom HVDC and AC technology, workshops, living areas and machine rooms will be accommodated in the topside, which is as tall as an eleven-storey residential building, 55 metres wide and longer than an Airbus A380. The platform’s support structure, known as the jacket, will be anchored in the Dollart Bay in water almost 30 metres deep. Once connected to the foundation the self-erecting topside will be elevated by means of a hydraulic jack-up system, to a height of around 20 metres above the surface of the water.