Multiline Ring Anchor system for floating offshore wind turbines

Abstract

The trends in the offshore wind industry have shown floating offshore wind turbines (FOWTs) technology and installation in deep waters due to stronger, more consistent wind resources and mitigation of aesthetic issues. Nevertheless, the high capital cost of the support systems remains a primary obstacle. Thus, this study presents a novel, integrated, and networked multiline ring anchor (MRA) system for FOWTs that can provide significant capital cost savings. Other attractive features of the anchor include versatility in regard to the range of soil conditions in which it can be deployed, relatively high geotechnical efficiency, capability for precise positioning and a deep embedment which provides for robust performance under unintended torsional loading. A limited comparative study of the MRA to a suction caisson anchor in soft clay shows the MRA to be clearly more efficient under horizontal loading, but only a marginally better under vertical loading. Incorporating keying flaps in the design has promise for eliminating the latter performance issue.