6D Building information modelling (BIM) for demolition waste management of semi-submersible wind turbines

The rapid global expansion of offshore wind is matched by an emerging wave of decommissioning. By the 2030s, over 30 GW of Europe's capacity will reach end-of-life (EoL), rising to 40 million tonnes of material waste globally by 2050, with blades alone contributing approximately 325,000 tonnes of waste per year in Europe if not effectively recovered. This shift presents a risk of waste accumulation and an opportunity to embed circular economy (CE) practices into infrastructure renewal. To address this challenge, this study develops a BIM-based framework for dismantling a semi-submersible floating wind turbine (FWT), combining 3D modelling, 4D time sequencing and component-level inventories. The analysis adopts three condition-based scenarios - intact, minor and major damage - reflecting the real uncertainty at EoL, where exposure to marine environments can produce highly variable outcomes. This structure allows engineers to assess recovery routes in a realistic manner, from high-value reuse to advanced recycling. Our new findings demonstrate that Scenario 1 enables reuse and delivers the lowest cost, time and CO₂e impacts, while enabling the highest-value CE applications. Scenario 2 introduces moderate repair burdens due to processing requirements and Scenario 3 is dominated by energy-intensive processes. By linking those results to cumulative inventory, the study provides a replicable digital catalog that captures component fate across scenarios. The creation of material passports / inventories provides traceability of resources, highlights landfill avoidance and supports market preparation for secondary materials. For engineers, the framework offers a reproducible, inspection-driven decision-support tool that links component conditions to dismantling schedules and CE pathways, informing planning and procurement in upcoming decommissioning projects of the offshore wind industry.