High-voltage direct current transmission (HVDC): the star technology for offshore wind farms


On the 27 th and 28 th of May Siemens organized a press trip, which FuturENERGY had the pleasure of being part of, to present the company’s capabilities in offshore wind technology. And what better way to present them that by flying across the North Sea in a small plane, over an area called the Helwin-Cluster to see Helwin 1, one of the offshore platforms developed and installed by the company, which will transport the energy produced by the Nordsee Ost and Meerwind offshore wind farms to the mainland. The journey then continued back on the ground, with a visit to the Helwin 2 platform, at that time still at the Heerema shipyards in Zwijndrecht, and now in place, offshore.

High-voltage direct current transmission technology, HVDC, basically consists of: a conversion station which converts alternating current to direct; electricity transmission cables; and another conversion station which transforms the current back into alternating current. Siemens launched its first project of this type of transmission system in China in 2009 and today has a portfolio of over 50 projects. This system is especially useful in the case of submarine connections, and particularly when it comes to transporting to land electricity produced by offshore wind farms.

Distances to the coast – not less than 80 km – make this the most appropriate technology for this type of project. Suffice it to say that HVDC technology has between 30% and 50% fewer losses than traditional AC transmission systems, and is able to transport between 30% and 40% more energy.

Article published in: FuturENERGY July-August 2014