The Borssele Alpha and Borssele Beta offshore high-voltage substations are approximately twenty kilometres off the coast of Walcheren and will connect the onshore network to the wind farms that will be built in the Borssele 1-2-3-4-5 areas. Alpha and Beta convert the power supplied by the wind turbines into a high voltage, which is further increased to 380 kV at the receiving station in Borssele for distribution in the national high-voltage grid. Both are being built by HSM Offshore in Schiedam. Sif will deliver the foundation tubes for the jackets for both stations: six per high-voltage substation.

Location: North Sea, 20 kilometres off the coast of Walcheren

Dimensions of piles: 6x Ø 2.134 mm x 50 - 80 mm wall thickness per jacket
Alpha 71.04 meters each
Beta 73.44 meters each

Total weight: Topsides 7400 tonnes
Jackets 5800 tonnes, including cable deck and J-tubes

Piles 2800 tonnes

Total capacity: 1400 MW (2 x 700 MW)
Intake voltage: 66 kV
Export voltage: 220 kV

Ready for connection:
Borssele Alpha - August 2019
Borssele Beta - August 2020

HSM Offshore is a large Dutch shipyard that is involved in engineering, purchasing, manufacturing, installation, and commissioning of multi-disciplinary oil or gas production platforms, offshore high-voltage substations, and other heavy offshore structures. HSM has a longstanding cooperation with Sif. The first projects that HSM and Sif carried out together were decades ago, when Sif only operated in Roermond. The cooperation has a rich history in which the commercial contact is exceptionally good. There are no problems between us, and we’ve never had any,’ explains Peter Ruimers, Senior Buyer at HSM Offshore/Steel Structures. ‘What is important is the dynamic way of interacting, taking requirements into account, and also dealing with each other in a good, normal way. The men from Limburg always bring a vlaai (sweet tart) for us when they come this way. It may seem like a small gesture, but it really symbolizes the good quality contact that makes the cooperation with Sif so valuable.

According to Peter Ruimers, Sif stands out from the competition in two ways. ‘On the one hand, it is naturally down to the product they supply. After all, few companies are able to produce such high quality piles with a diameter of more than one and a half metres. On the other hand, one of Sif's strongest features is its reliability. In the multi-million industry of the offshore wind market, there is no room for error whether in production or delivery. Sif is acutely aware that if they do not deliver at the agreed time, we will not be able to proceed,' Peter continues. ‘That could result in extra costs amounting to hundreds of thousands. Small mistakes or delays can cause unbelievably critical situations. We simply cannot proceed if there is a deviation in the quality or delivery. Without Sif's piles, the jackets would sink into the ground. That proven reliability is therefore essential.’