TenneT Seeks Horizontal Directional Drilling Contractor for Hollandse Kust Zuid Connection

TenneT is looking for a contractor who will carry out horizontal directional drilling (HDD) works for the connection of the Hollandse Kust Zuid wind farm area. 

Image source: TenneT

The awarded company will be in charge of the design, engineering, manufacturing, nearshore, landfall and onshore installation of underground high-density polyethylene (HDPE) pipelines installed by horizontal directional drilling. The contractor will also deliver all materials, install the HDPE pipelines with additional length, and clean and test the HDPE pipelines before and after installation,

Furhermore, the scope covers the installation of a messenger wire, sealing during wet storage period, as well as the temporary lay-down of additional length on seabed, with easy removable ballast.

Cable pull-in is not part of the scope of this tender.

Deadline for submission of offers is 22 December 2017, with the works expected to be carried out in 2019.

The design and project execution will be done in close collaboration with the cable contractor, who will be chosen in a separate tender procedure.

The grid connection of the Hollandse Kust Zuid wind farm area will consist of two offshore HVAC substations and cable systems. Each cable system will comprise two circuits, with each circuit consisting of one three-core 220kV AC subsea cable, which will also be used for the onshore part. The landfall of the cables will be done via four pre-installed underground HDPE pipelines between seabed and landstation.

In October 2016, TenneT informed that the Maasvlakte North zone was identified as the most suitable landfall location for onshore cables which will connect four 350MW offshore wind farms in the Hollandse Kust Zuid zone to the grid.

The four wind farms at the zone will be connected to the grid between 2018 and 2021, according to current plans.

The tender for the construction of offshore wind farms at the first two sites at the Hollandse Kust Zuid zone will open on 15 December.

Photo: Image source: TenneT