Projections anticipate wind energy as the EU's primary electricity source by 2050. Despite EU leadership in wind power component manufacturing, heavy reliance on imported raw materials, many critical, poses challenges. Understanding wind turbine material cycles' connection to raw materials supply chains is limited, hindering efforts to establish a domestic supply chain. To address this gap, a Multilayer Material System Analysis (MMSA) is employed at the EU level, estimating flows and stocks of six metals (aluminium, copper, iron, manganese, neodymium, and nickel) in wind turbines, differentiated by drivetrain technologies. Five indicators, including self-sufficiency potential (SSP), were calculated for each metal and for wind turbines overall. In 2021, around 4100 kt of material entered the use phase, with 1130 kt leaving at end-of-life; 88 % due to component failures, and 12 % from decommissioning. Recycling processes recovered around 990 kt. Nickel, manganese, aluminium, and neodymium exhibit SSP values below 50 %, with Nd being particularly critical, resulting in a zero SSP and 100 % End-of-Life Downcycling Rate (EoL-DR). A comprehensive understanding of wind turbine value chains enables tailored policy measures to maximize product and component circularity, thereby prolonging material lifecycles. This study serves as a foundation for further analysis exploring the impacts of various circular strategies.