A state-of-the-art concept integrating a deepwater floating offshore wind turbine with a steel fish-farming cage (FOWT-SFFC) is presented in this paper. The configurations of this floating structure are given in detail, showing that the multi-megawatt wind turbine sitting on the cage foundation possesses excellent hydrostatic stability. The motion response amplitude operators (RAOs) calculated by the potential-flow program WAMIT demonstrate that the hydrodynamic performance of FOWT-SFFC is much better than OC3Hywind spar and OC4DeepCwind semisubmersible wind turbines. The aero-hydro-servo-elastic modeling and time-domain simulations are carried out by FAST to investigate the dynamic response of FOWT-SFFC for several environmental conditions. The short-term extreme stochastic response reveals that the dynamic behavior of FOWT-SFFC outperforms its counterparts. From the seakeeping and structural dynamic views, it is a very competitive and promising candidate in offshore industry for both power exploitation and aquaculture in deep waters.

This study presents a new concept design combining multiple megawatt (MW) vertical-axis wind turbines (VAWTs) and a solar array with a floating steel fish-farming cage. This combined wind–solar–aquaculture (WSA) system is intended to utilize the ocean space and water resources more effectively and more economically, while greatly shortening the payback period of investment in offshore power generation. The details of this WSA design are described, showing that a square-shaped fishing cage serves as a floating foundation for the 7600 m² solar array and four multi MW VAWTs. The WAMIT program based on potential-flow theory is employed to obtain the WSA’s motion response amplitude operators (RAOs) in sinusoidal waves of varying periods. The motion RAOs indicated that the proposed concept possesses better hydrodynamic seakeeping performances than its OC3Hywind spar and OC4DeepCwind semi-submersible counterparts. A potential site located in the northwest South China Sea is selected to deploy the WSA. Its feasibility is then examined in terms of the hydrodynamic motions and structural dynamic response driven by wind, waves, and current. Fully coupled time-domain simulations are carried out for 50-year survival conditions. The whole structure exhibits outstanding performance for its small motions in random wind and seas. Moreover, under these survival conditions, the top accelerations and tower base stresses of the VAWTs and mooring line tensions readily meet the design requirements. Technically, the WSA has strong competitiveness and wide prospects in the offshore industry for both power exploitation and marine aquaculture in intermediate and deep waters.