Integrated System Design for a Large Wind Turbine Supported on a Moored Semi-Submersible Platform

• Published in: Journal of marine science and engineering 2018-01, Vol.6 (1), p.9
• Main Authors: Liu, Jinsong, Thomas, Edwin, Manuel, Lance, Griffith, D., Ruehl, Kelley, Barone, Matthew
• Format: Article
• Language: English
• Subjects: Capacity; Catenary; Design; Design engineering; design load; Dynamic characteristics; Dynamic response; Dynamic stability; Electric power generation; Energy; Environmental management; Finite element method; Floating structures; Integral equations; Irregular waves; Iterative methods; Mathematical models; Mooring systems; Offshore; Offshore drilling rigs; Offshore operations; offshore wind turbine; Operators (mathematics); Performance evaluation; Regular waves; Renewable energy; Renewable resources; Resource management; response amplitude operator (RAO); Scaling; Sea states; Semisubmersible platforms; Stability analysis; Static stability; stochastic dynamics; Stochasticity; Structural stability; Submersible platforms; Submersibles; Systems design; Turbine engines; Turbines; Turbulence; Vertical stability; Wave excitation; Wind fields; Wind power; Wind turbines
• ISSN: 2077-1312; 2077-1312
• DOI: 10.3390/jmse6010009

Over the past few decades, wind energy has emerged as an alternative to conventional power generation that is economical, environmentally friendly and, importantly, renewable. Specifically, offshore wind energy is being considered by a number of countries to harness the stronger and more consistent wind resource compared to that over land. To meet the projected “20% energy from wind by 2030” scenario that was announced in 2006, 54 GW of added wind energy capacity need to come from offshore according to a National Renewable Energy Laboratory (NREL) study. In this study, we discuss the development of a semi-submersible floating offshore platform with a catenary mooring system to support a very large 13.2-MW wind turbine with 100-m blades. An iterative design process is applied to baseline models with Froude scaling in order to achieve preliminary static stability. Structural dynamic analyses are performed to investigate the performance of the new model using a finite element method approach for the tower and a boundary integral equation (panel) method for the platform. The steady-state response of the system under uniform wind and regular waves is first studied to evaluate the performance of the integrated system. Response amplitude operators (RAOs) are computed in the time domain using white-noise wave excitation; this serves to highlight nonlinear, as well as dynamic characteristics of the system. Finally, selected design load cases (DLCs) and the stochastic dynamic response of the system are studied to assess the global performance for sea states defined by wind fields with turbulence and long-crested irregular waves.