Offshore Wind

Hollandse Kust (noord) Offshore Wind Farm | OHVS
North Sea, the Netherlands
Hollandse Kust (noord) Offshore Wind Farm | OHVS

Smulders and EQUANS are building the offshore substation for the Hollandse Kust (noord) offshore wind farm for TenneT.


About the wind farm

The Hollandse Kust (noord), (west Alpha) and (west Beta) offshore platforms will be located in the North Sea along the Dutch coast. Forty percent of the Netherlands’ electricity needs will come from offshore wind farms by 2030. TenneT will realise the grid connections for these wind farms. These three 700 MW platforms will be the fifth, sixth and seventh large-scale grid connections for offshore wind energy in the Netherlands to be constructed and operated by TenneT. Further background information can be found on and and


Scope of work

Following a European tender procedure, TenneT TSO B.V. has selected the joint venture EQUANS – Iemants (subsidiary of Smulders) to construct an offshore transformer station for the Hollandse Kust (noord) wind farm zone.


Iemants is responsible for the engineering, procurement and construction of the steel structures for both the topside and jacket. All works are performed inhouse, at the Smulders’ production facilities in Arendonk, Balen and Hoboken (Belgium). The final assembly takes place at the EQUANS yard in Hoboken. The jacket is being assembled at the yard in Vlissingen (the Netherlands).  


EQUANS is responsible for the engineering, procurement, integration, construction and testing (on- and offshore) of all LV, MV, HV and auxiliary systems for the jacket and topside of the Hollandse Kust (Noord) offshore transformer station. The engineering, procurement, construction, integration and onshore testing for the topside systems will take place at the EQUANS yard in Hoboken (Belgium). For the jacket, these activities will take place in Vlissingen.


Key figures and planning

This offshore transformer station consists of a 45-meter-high jacket of 1,930 T and 870 T piles to be placed in 24-meter water depth and a topside structure consisting of 4 decks weighing approx. 4,100 T. The topside structure is 47 meters long, 35 meters wide and 25 meters high (excluding antenna tower and top deck crane).


Load-out and installation of the jacket took place in the fall of 2021. On 12 September, the impressive load out of the Hollandse Kust (north) topside took place. Two weeks after the successful load out, the topside for the Hollandse Kust (north) substation left the Hoboken yard. It was shipped to the port of IJmuiden until weather conditions were right for offshore installation. On the night of Monday 3 October to Tuesday 4 October 2022, the offshore installation took place 18.5 kilometres off the coast of Egmond aan Zee.



Installation transformers

Move out

Load out topside

Sail away topside