Roermond, The Netherlands - 20 May 2019. Sif Holding n.v. will manufacture two monopiles for the Two Towers Borssele V innovation site. A number of innovations will be applied in the project such as a slip joint connection, seabed protection and a full aluminum sprayed coating.

One of the monopiles will have a slip joint connection. The slip joint connection is the connection between the monopile foundation and the transition piece that connects the foundation and the tower. This has traditionally been a flanged or a grouted connection. 

In contrast, one foundation will be equipped with conical-shaped end pieces of the monopile and transition piece, which are stacked like coffee cups in a cupboard. This connection will save installation time offshore. While this technique has been applied successfully onshore, it was only used in offshore projects on a test basis. 

The coating for the other monopile will be aluminium sprayed for a major part of the surface with a view to avoiding corrosion combined with minimizing the required maintenance activities.

Fred van Beers: "Sif considers it important to be part of innovations such as the ones being applied by our client Two Towers at Borssele V. These innovations are aimed at either saving costs on the manufacturing of the products and/or the installation and its maintenance at sea or at ensuring an improvement of the environmental impact on sea life. The offshore wind industry is still young and innovations such as these help to further decrease the levelized costs of energy from offshore wind."

Two Towers is the consortium for the Borssele V project that comprises Van Oord, Investri Offshore and Green Giraffe. Grid connection is scheduled for 2021.