Modelling of coupled floating turbine, mooring & power cables in wind, wave & current (Xu & Srinil, OMAE2015-41512)

EU has identified an ambitious goal of obtaining 20% of total energy consumption requirements with renewable energy by 2020. In particular, the target to reach 50 GW of offshore wind energy is encouraging. Offshore fixed (monopile, jacket, gravity base) & floating (spar, semisubmersible) wind turbine foundations have become an innovative and promising technology in deep-water (< 500m) locations having high wind energy densities and eliminating the issues of visual impact & noise. These offshore wind resources will make a commercial and technological development of OWTF more economically attractive in the near future.

Depending on the water depth, geotechnical and environmental wind-wave-current conditions, the motions of floating foundations are dynamically controlled by the mooring systems which represent major cost components and can certainly influence overall turbines performance characteristics. In addition, subsea power cables are part of the floating systems, being key components for transporting energy from wind turbines to offshore substations and onshore facilities. FlexNARA is developing an intelligent approach to optimize mooring/power cable design with a fully coupled nonlinear dynamics and reliability analysis alongside in-house experimental tests.

Modelling an offshore wind turbine jacket