Static Calculation on Integrated System of Offshore Wind Turbine Foundation and Aquaculture Cage

Abstract

[Introduction] With the continuous increase of offshore wind farms, conflicts in the use of marine areas has become increasingly severe. The integrated development of offshore wind power and aquaculture has attracted growing attention, with various structural designs for wind turbine foundations integrated with aquaculture cages being proposed. However, most of these designs are still in the conceptual stage and far from practical engineering applications. [Method] Based on the requirements of equal netting mass, equal biomass of marine growth attached to the netting, and equivalent hydrodynamic performance of the netting, the paper introduced an efficient method to calculate the equivalent loads of the cages. Considering the design loads of a 14 MW wind turbine and marine hydrological conditions, a jacket foundation structure suitable for the 14 MW offshore wind turbines was designed, integrating internal and external aquaculture cages to propose two integrated systems combining jacket foundations and marine aquaculture cages. Using the Morison model and considering the impact of nonlinear waves, static analyses of different designs were conducted in SACS based on the proposed equivalent modeling method for the cages. [Result] The study shows that the integration of internal and external cages with the jacket foundation has little to negligible impact on the first and second order frequencies of the overall system and a more significant effect on the third order frequency. The rotation condition is the controlling case, and after adding internal and external aquaculture cages, local reinforcement of the jacket foundation is required. Computational results for the integrated designs of the 14 MW offshore wind turbine jacket foundation with internal or external cages meet the regulatory design requirements. [Conclusion] The analysis results provide a reference for the engineering application of the integrated system design of offshore wind turbine foundations and marine aquaculture cage systems.

Keywords

• 14 mw wind turbine
• jacket foundation
• aquaculture cage
• equivalent load
• static calculation