Presentations

Abstract

The Slip Joint is a connection type that was first used in the 1990's as a connection between tower sections of onshore wind turbines. In 2003, it was proposed as a connection between monopile and transition piece in foundations of offshore wind turbines, but was picked up as a serious connection much later. In 2020, after an extensive research, testing and qualification program, the Slip Joint received a DNV A-level component certificate and was used for the first time as a full-size submerged connection in one of the 9.5MW wind turbines in the wind farm Borssele V, developed by Two Towers and designed and built by Van Oord. Borssele V is developed as an innovation site where new technologies can be demonstrated. At the same time, it is a commercial wind farm, designed and certified for a lifetime of 25+ years, making it no different than large scale wind farms. With the installation on Borssele V, the Slip Joint technology reached TRL level 8. Over the last four years, the Borssele V submerged Slip Joint has been monitored closely, to gather data on the behaviour of a Slip Joint and to draw lessons for future improvement of the technology. This presentation will summarise the development of the Slip Joint and highlight the Borssele V monitoring program and its results.