How can an innovative single point mooring system reduce the LCOE of Floating Offshore Wind? A showcase of recent outcomes from the PivotBuoy project

Joao Neves, Director of Strategy and Business Development, X1 Wind
In recent years, an increasing number of floating solutions are proposing the use of a single point mooring (SPM) system instead of a multiple mooring system, to allow the system to self-align passively with the wind. For the past two years X1 Wind has together with eight other partners from five different countries worked on the PivotBuoy project, awarded under the H2020 program, with the objective to demonstrate an innovative single point mooring system (SPM). The PivotBuoy project will demonstrate a fully functional prototype of the PivotBuoy system (in a downwind configuration) integrated with a downwind-adapted Vestas V29 at PLOCAN’s test site in the Canary Islands by the end of 2021. By combining the advantages of a SPM with a small Tension-Leg Platform (TLP) in a downwind configuration, X1 Wind’s floating structure can passively weathervane and self-align with the wind. This enables a complete redesign of the floating structure and an easy installation procedure. The SPM and TLP of the PivotBuoy system can be easily pre-installed, while the floating platform is wet towed to the site with local vessels and easily connected to the PivotBuoy quick connection.

X1 Wind’s pyramidal platform eliminates the traditional vertical tower and thus the large bending moments on the tower base. By using a downwind configuration, the pyramidal floating structure allows the structural elements to work more efficiently in tension and compression, which significantly reduces the weight of the platform.

The findings of the PivotBuoy project will reveal the advantages of this SPM system on performance and long-term cost reduction potential. By the time of the conference in March 2022, X1 Wind will be able to share results about the following:

• Validation data about the innovative single point mooring system (PivotBuoy)
• Operational experience on the installation of the system.
• Downwind turbine performance in the X1 Wind platform configuration.

The implication of these results could open the door for more holistic floating wind designs, where the floating structure, mooring system, turbine tower and the turbine is re-invented to facilitate significant LCOE reduction. SPM technology has been widely used in Oil & Gas for decades, specifically for the connection of FPSOs (Floating Production, Storage and Offloading), but remains unknown to the majority of the wind industry. A few new entrants in the floating wind sector are proposing to use SPM technology to connect their floating platforms. Delegates at the FWS ’22 conference will learn about the advantages of implementing this technology with floating offshore wind platforms (weight and LCOE reduction), as well as the challenges (such as the possible misalignment of wind and waves and the influence of cross-currents) in comparison to current mooring solutions, and how X1 Wind has dealt with them in the PivotBuoy project through the part-scale design, manufacturing, assembly, installation and firsts months of operation.