DHI, LICengineering Design Scour Protection for Danish OW Trio

DHI and LICengineering have designed the scour protection systems for three Vattenfall’s Danish offshore wind farms, which is expected to save 30% in installation costs.

The companies provided the systems for the Vesterhav Syd and Nord nearshore wind farms and the Kriegers Flak offshore wind project, which together have 113 turbines producing a combined capacity of 950MW.

Usually, scour protection systems are applied in two steps, including the installation of a filter layer around the monopile base consisting of finer material and the installation of an armor layer on top of the filter material.

The monopiles may be installed before both layers or in between the two, which in either case implies that the total installation comprises three steps, LICengineering said.

Modern design principles have enabled the use of one stone material consisting of wide-graded rock, thus neglecting the traditional two-layer solution, the company added, emphasizing that the wide-graded rock material encompasses both the filter and armor effect, and can be installed in one step.

Considering the installation of the stone material and monopiles, the installation procedure has been reduced from three to two steps and as a result cost reduction has been achieved, LICengineering concluded.

“DHI and LIC Engineering designed the application of wide-graded rock as an innovative solution for scour protection at the three offshore wind farms, and this has shown to be a viable design option with great potential for cost savings,” said Victoria Ruiz Gomez, Project Manager Offshore Foundations at Vattenfall.

The Vesterhav Syd and Vesterhav Nord offshore wind farms will comprise a total of 41 8MW turbines located off the west coast of Jutland. The construction of the two projects has been postponed to 2023, instead of the originally planned 2020.

The 605MW Kriegers Flak offshore wind farm will comprise 72 Siemens Gamesa 8MW turbines scheduled to be fully commissioned before the end of 2021.