Optimizing Offshore Wind Turbine Jacket Structures For Mass Reduction And Embodied Carbon Savings: A Multi-Constraint Topology Optimization Study Using Ansys

Abstract

Offshore wind energy is a cornerstone of global decarbonization pathways, yet jacket support structures account for 20–35% of the total installed cost and a significant fraction of the lifecycle embodied carbon of a fixed-bottom offshore wind turbine. Reducing the mass of jacket structures therefore delivers both economic and environmental benefits, with direct implications for marine resource conservation and CO2--equivalent emission reduction. This study presents a multi-constraint topology optimization framework for a small-scale demonstrator jacket structure, implemented in ANSYS Mechanical using the Solid Isotropic Material with Penalisation (SIMP) method, and evaluates the environmental implications of the resulting mass reduction. The framework couple’s compliance minimization with simultaneous constraints on retained mass fraction, von Mises stress, minimum/maximum member size, and four-fold cyclic symmetry about the tower axis to ensure manufacturability. Two extreme wind load cases (perpendicular and 45° to the jacket face) were derived following the IEC 61400-3 design philosophy with a partial safety factor of 1.35 and analyzed on a mesh-converged finite element model comprising BEAM188 and SHELL181 elements. A three-level mesh independence study confirmed displacement and stress convergence within 1.8%. The optimized jacket retained 28.8% of the baseline mass (corresponding to 312 kg of structural steel saved per demonstrator unit) while increasing von Mises stress utilization from 0.47–0.51 in the baseline to 0.64 0.68 in the optimized design, remaining safely below the allowable limit of 230 MPa for S235JR structural steel. Using a representative embodied-carbon factor of 2.45 kg CO2per kg of virgin structural steel, the per-unit mass saving translates to approximately 31.85 kg CO2- avoided in the material production phase alone; scaling to a notional 100-unit deployment yields an avoided emission of approximately 3.2 tones CO2-The study also discusses marine ecosystem implications, the role of reduced material throughput in circular-economy pathways, and the limitations imposed by the demonstrator scale and the static-only loading framework. The results support topology-driven design as a meaningful contributor to sustainable offshore wind deployment.