Simulation-based optimization of Impressed Current Cathodic Protection (ICCP) systems for offshore wind turbine monopiles

Impressed current cathodic protection (ICCP) is widely used to mitigate internal corrosion of offshore wind monopiles, but its design remains challenging because coating condition, geometry, and exposure history strongly affect current demand. This study develops an experimentally supported, simulation-based optimization framework for internal monopile ICCP by combining Linear Polarization Resistance measurements, 3D COMSOL Multiphysics® modeling, and Genetic Algorithm optimization. Polarization curves for five representative surface states, including bare steel with calcareous deposits and two coated systems at different exposure times, are implemented directly as boundary conditions in a Secondary Current Distribution model. The model is first verified against a lab-scale ICCP setup and then applied to a full-scale monopile. The full-scale model is coupled to a Genetic Algorithm to minimize total anode current while satisfying the protection-potential constraints. Feasible optimized designs are obtained for all surface conditions. The results show that coating condition strongly influences ICCP current demand, with the commercial coating system providing the greatest reduction. Sensitivity and constrained optimization analyses identify the number of anodes and impressed potential as the dominant design variables, while anode radius and length have secondary effects. Overall, the framework provides a systematic basis for case-specific for energy-efficient ICCP design of internal monopiles.