📋 Case Study

Borssele III & IV Substation Jacket Corrosion Remediation

Localized pitting corrosion observed on jacket legs within 3 years due to sediment scour exposing bare steel beneath coating

🏗️ Project Overview

752 MW Dutch offshore wind farm (Shell, Ørsted)

🎯 Challenge

Localized pitting corrosion observed on jacket legs within 3 years due to sediment scour exposing bare steel beneath coating

🔧 Design Approach

Integrated real-time scour monitoring (acoustic Doppler profilers) + sacrificial anode re-design with localized high-output anodes and cathodic protection potential mapping

📐 Design Diagram

_corr − E_anode) / R_total = 2.4 A/anode Borssele III & IV Substation Jacket Corrosion Remediation Scour Exposure ADP Monitoring Sacrificial Anode CP Mapping

AI-generated project design illustration

📐 Key Calculations

Anode Current Output

I = (E_corr − E_anode) / R_total

Result: 2.4 A/anode

Ensured polarization threshold of −0.85 V vs. Ag/AgCl maintained during scour events

📊 Results

Extended remaining service life by 18 years; reduced inspection frequency from annual to biennial

💡 Lessons Learned

• •Scour modeling must include seasonal sediment transport variability
• •Coating repair protocols require underwater NDT validation prior to CP re-energization

✅ Key Takeaways

• 1Scour modeling must include seasonal sediment transport variability
• 2Coating repair protocols require underwater NDT validation prior to CP re-energization