2013, VSH, Walney Extension, Export Cable Landfall HDD Technical Assessment

Visser & Smit Hanab (VSH) have been appointed by DONG energy (DE) to provide a high level assessment of the export cable landfall(s) associated with the extension to the existing Walney Extension Offshore Windfarm. The project involves the landing of 220kV export cable systems. It is intended that the cable connections shall be installed by means of Horizontal Directional Drill (HDD), exiting onto the beach within the intertidal zone, beyond which the cable will be buried beneath the sea bed out to the Offshore Windfarm. The HDD option is driven by the sensitive salt marshes at the landfall location and the need to cross the sea defence structure. This report is intended to provide a high level overview of the viability of installing the landfalls by means of HDD at the above location. The study will take into account the design of the HDD profiles, soil conditions, site constraints and set up and pipe stringing locations, based on the available data.