Assessing the Performance and Environmental Effects of Offshore Wind Cathodic Protection: Modeling and Field Insights

ABSTRACT This study evaluates the expected long‐term performance and environmental effects of galvanic anode cathodic protection (GACP) systems for offshore wind monopiles. A numerical model was developed and compared to field data to simulate protection performance over a 25‐year design life. The model incorporates key factors such as coating degradation, oxygen limiting current density, surface film resistance, dimensional changes of the anode over time, and anode quantity. Based on the simulations, the metal emission of Al‐Zn‐In anodes per monopile was estimated at approximately 20%–36% of the total anode mass, corresponding to configurations with 50 and 25 anodes, respectively. This results in total metal emissions of 0.091–0.111 ppm Al and 0.005–0.006 ppm Zn. While significantly exceeding natural background levels, the predicted concentrations remain 11–13 times below reported toxicity limits for aluminum and 6–8 times below those for zinc. The results highlight the importance of integrating field data and long‐term monitoring to validate environmental impact assessments and ensure CP systems are both effective and sustainable.