Deltares

Deltares provided engineering consultancy support to HSM Offshore relating to the scour protection design for TenneT’s Borssele Alpha & Beta offshore high-voltage substation (OHVS) platforms in the Dutch North Sea. These platforms form part of the offshore grid infrastructure that connects the Borssele Wind Farm Zone to the onshore transmission system; Borssele Alpha is the 700 MW HVAC connection serving Borssele Sites I & II. Deltares’ work built on model tests it carried out in 2016 to investigate scour development and conceptual scour protection for the platforms, originally commissioned by TenneT. After HSM Offshore was awarded the 2017 contract for construction and installation of both platforms, Deltares was engaged to update and develop the detailed scour protection designs. The scope included using the earlier model-test findings and Deltares’ experience with comparable offshore structures to optimise the scour protection layout and address secondary effects such as edge scour and potential impacts from installation vessel spud-can footings. The objective of the consultancy was to reduce design and installation risk and avoid additional model testing, supporting safe and cost-effective execution of the offshore substation foundation and platform installation programme.