IEC 61400-22:2023 Annex D – Offshore Wind Decommissioning Reef Conversion Protocol

IEC 61400-22:2023 Annex D formalizes a standardized, science-based framework for evaluating, designing, approving, and monitoring the intentional reef conversion of offshore wind infrastructure—primarily monopile, jacket, and gravity-based foundations—following operational end-of-life. Unlike ad hoc 'reefing' practices, this annex mandates rigorous pre-conversion assessment including benthic baseline surveys, hydrodynamic modeling, corrosion state analysis, and risk evaluation for invasive species transport or hazardous material release (e.g., residual coatings, grouting compounds). It prescribes minimum design thresholds for structural longevity (>50 years post-conversion), scour mitigation measures, and fish-habitat functionality metrics (e.g., surface complexity index, void space volume per unit area). Implementation requires multi-stakeholder coordination across marine spatial planning authorities, fisheries management bodies, environmental agencies, and certification bodies—ensuring alignment with regional directives such as the EU Marine Strategy Framework Directive (MSFD) and the OSPAR Convention. Crucially, Annex D distinguishes reef conversion from partial removal, requiring demonstrable net ecological benefit verified via adaptive monitoring protocols over minimum 10-year post-deployment periods.