Statistical analysis of floating hybrid wind–wave energy systems

Recent advances in the development of floating offshore wind turbines have also generated great interest in hybrid wind–wave energy systems due to the resource and technological complementarity of both systems. Over the past decade, a large amount of research has been conducted to uncover the benefits of combining floating wind turbines with wave energy converters and to propose and evaluate new hybrid system designs. The aim of this study is to identify trends, patterns and insights of the hybrid wind–wave energy systems by collating, reviewing and analysing the data available in the literature. The statistical analysis is presented for the design aspects of the hybrid wind–wave system, power production of wave energy converters, methodologies used to investigate the hybrid system dynamics, and the reported findings. The analysis indicates that research on hybrid systems lags behind floating platform development by approximately five years, with a predominant focus on 5 MW wind turbines installed on semi-submersible platforms and coupled with heaving wave energy converters. However, hybridisation efforts must keep pace with advances in modern wind energy technologies. The share of wave energy in the total power production of a hybrid platform is less than 10 %, and the median rated power of a single WEC is close to 100 kW. Wave energy converters do not tend to change the wind turbine power production, while an increase in platform motions was observed, also negatively affecting loading on mooring lines. Therefore, new designs need to investigate motion suppression in order to explore additional benefits of the hybridisation, such as mooring and tower bending load reduction. Furthermore, integrating wave energy with a floating wind turbine increases the levelised cost of energy of the combined project, underlying the challenges in providing a techno-economically viable solution, which also should be considered in the design process.