Dong installs Borkum substation

Denmark’s Dong Energy has completed the installation of the inner-park substation at its Borkum Riffgrund 1 offshore wind project off Germany’s North Sea coast, and says it will start erecting foundations at the 277MW wind farm in early 2014. 

The substation will receive power from the wind park’s 77 Siemens 3.6MW turbines, then transport it to a converter platform run by transmission system operator TenneT, which transforms alternating current (AC) from this and other wind farms into direct current (DC) to be flowed to the shore.

“Borkum Riffgrund 1 is our first German wind farm in the North Sea. We gain a lot of experience (here) from which our future German wind farms can profit,” says Christoph Mertens, senior director and head of Dong Energy Wind Power in Germany.

Installation of the substation started on 1 August when it was shipped from Aalborg in Denmark. The construction components were loaded onto a floating pontoon and shipped to the construction site 37km northeast of the German island of Borkum.

The foundation was placed on eight monopiles that have been driven into the seabed and anchored.

In order to reduce the noise from the construction works, a three-fold bubble curtain was applied, Dong says. At the end, the top side was placed on the platform by means of a jack-up crane vessel. 

The total weight of the substation is 3,500 tonnes, and it covers an area of 465 square metres. 

The company expects commissioning of Borkum Riffgrund 1 in 2015 at the latest.

Dong has recently shed onshore wind assets in several countries after unveiling a new strategy in February to focus on offshore wind.

The company plans to quadruple its current offshore wind capacity from 1.7GW to 6.5GW, with Germany one of its core markets.