Prospective material flow analysis of the end-of-life decommissioning: Case study of a North Sea offshore wind farm

Early offshore wind farms approach their decommissioning phase, yet a lack of precedents, potential legal bottlenecks, inadequate treatments and a lack of applicable circularity indicators, leave the sector unprepared, encompassing a risk of valuable materials loss. This paper presents a first-of-its-kind circularity analysis of the prospective decommissioning scenario of a North Sea wind farm, introducing and applying new circularity indicators. From the site-specific primary data, a bill of materials and material flow analysis was established, differentiating between secondary applications and end-of-life destinations. The main share (80 %) of the installed mass originated from scour protection, acting as hotspot to the 84 % of materials remaining in situ. The collected fraction recycling rate approaches 90 %. However, the substantial discrepancies between components and materials implicate a need for component or material-specific targets to avoid valuable material loss. Introducing such collection or recycling targets could encourage more circular decommissioning practices along the value chain.