11.07.2013 - Project Log

A substation becomes seaworthy

It is ready: after a construction period of one and a half years, the offshore substation for the wind farm has just about been completed on time. The two transformers, all cables, switchgears and supply areas have been set up so that the construction is now ready for its future task of pooling together the electricity from all 80 wind energy plants at sea and bringing it to the required transport voltage.

On 29 June, the substation rolled slowly - very slowly - out of the production hall. It moved forward centimetre by centimetre on a multiwheeler, which is a sort of "centipede on wheels". It is approximately 100 metres to the quayside, where the barge to transport it to the DanTysk construction site is moored on thick lines and is waiting for the freight. The helicopter landing platform is still to be installed before loading begins, thus guaranteeing that the staff can safely reach the wind farm for maintenance and repair works even in harsh weather conditions.

But how does someone load a 3,000 tonne-heavy 'monster' onto a transport barge without the latter losing its balance in the water in the rocess? The professionals at the Hollandia shipyard in Rotterdam have experience. The transport barge consists of several air chambers that are partly filled with water. The weight of the substation would normally force the barge downwards during the loading process. But the experts at the scene pump water out of the air chambers at exactly the right moment, thus increasing the lifting force. At this point, the incoming tide also helps nicely to ensure that the loading area is always at exactly the same height as the quayside and that the substation can be safely rolled over the ramp onto the barge. Precision work - and the water level is checked time and time again. Such a loading process lasts an entire day until the substation can be safely put down on its holding brackets on the barge. In the next few days, the foundation, a jacket structure, will also find a home on the barge together with the stakes to anchor it into the seabed. The next instalment, "A substation sets sail", will follow at the end of July. 

For the accompanying blog entry

For more photos 

More on the substation