Optimal Design and Performance Analysis of a Hybrid System Combining a Semi-Submersible Wind Platform and Point Absorbers

Abstract

Integrating point absorber wave energy converters (PAWECs) and an offshore floating wind platform provide a cost-effective way of joint wind and wave energy exploitation. However, the coupled dynamics of the complicated hybrid system and its influence on power performance are not well understood. Here, a frequency-domain-coupled hydrodynamics, considering the constraints and the power output through the relative motion between the PAWECs and the semi-submersible platform, is introduced to optimize the size, power take-off damping, and layout of the PAWECs. Results show that the annual wave power generation of a PAWEC can be improved by 30% using a 90° conical or a hemispherical bottom instead of a flat bottom. Additionally, while letting the PAWECs protrude out the sides of the triangular frame of the platform by a distance of 1.5 times the PAWEC radius, the total power generation can be improved by up to 18.2% without increasing the motion response of the platform. The PAWECs can reduce the resonant heave motion of the platform due to the power take-off damping force. This study provides a reference for the synergistic use of wave and wind energy.

Multibody Analysis of Wave Energy Converters and a Floating Platform in the Time Domain

“…Zhou et al [19] studied the dynamic behaviors of multiple heaving WECs and semisubmersible platforms, revealing that a prominent new power peak emerges when the platform and WECs are in a synchronized state. Furthermore, various parametric studies were conducted to optimize the system by introducing frequency-domain-coupled hydrodynamics, considering the constraints and power output through the relative motion between the integrated WECs and the semi-submersible platform [20]. Kamarlouei et al [21] explored a hybrid system comprising 12 WaveStars surrounding a semisubmersible platform, revealing that the platform's heaving and pitching motions could be effectively mitigated by WECs with appropriately tuned damping in the power take-off (PTO) system.…”