Risk-Cost Analysis of Three Mooring Schemes of FOWTs with One Mooring Line Failure

Offshore wind power has great potential for application, but its high investment cost makes cost reduction imperative. Currently, most offshore wind projects adopt nine-line mooring systems for safety, while the risks and costs of six-line and three-line mooring systems remain unclear. This study examines the failure patterns and risk-cost relationships of three-line, six-line, and nine-line mooring systems under extreme environmental conditions with the failure of a single mooring line. The study indicates that, after the mooring failure, the platform drift in the three-line mooring system is significantly greater than that in the six-line and nine-line mooring systems. Although the mooring line tension and anchoring force increase after failure in all three mooring schemes, they remain within safe limits. The six-line mooring system is proved to be a well-balanced solution that considers both risk and cost.

Keywords: Floating offshore wind turbine, Mooring scheme, Failure pattern, Risk-cost relationship.