Abstract
The offshore wind energy sector is rapidly evolving, with floating wind turbines playing a pivotal role in expanding renewable energy capacity in deep-water regions. Central to the stability and safety of these floating structures are mooring systems, which have traditionally relied on steel wire ropes[TM1.1]. However, in recent decades, synthetic fiber ropes have gained prominence due to their favorable mechanical properties, including high strength-to-weight ratios, ease of deployment, and resistance to corrosion. Commonly used synthetic fibers include: polyester, polyamide, ultra-high molecular weight polyethylene (HMPE), and aramid, each offering distinct advantages and challenges in marine environments (Weller et al., 2015).
Despite the increasing deployment of synthetic mooring lines, the end-of-life management and recycling of these materials remain underexplored. While polyester and polyamide ropes have established recycling pathways—particularly informed by practices in the aquaculture and fisheries sectors—the circularity potential of HMPE and aramid ropes is less well understood. Emerging evidence suggests that polyamide ropes can be recycled into yarns for textiles such as swimwear and activewear, while aramid fibers are currently repurposed into pulp for use in brake pads and other industrial applications. Novel technologies, some at the patent stage, are showing promise in enabling closed-loop recycling of HMPE and aramid ropes back into yarns, potentially enhancing material circularity (da Silva et al., 2025).
Several fiber rope manufacturers are actively pursuing sustainability initiatives, including take-back programs and recycling schemes aimed at reducing environmental impact. Current efforts focus on mechanical and physical repurposing strategies, such as converting decommissioned ropes into non-woven fabrics for use in industries like automotive, construction, home furnishings, and geotextiles. These approaches offer an alternative to thermal recycling, which involves melting and repalletizing[TM2.1] the ropes. Aramid producers, for instance, are developing circular systems that incorporate mechanical, physical, and chemical recycling pathways to recover and reuse materials at the end of their operational lifespan. Similarly, HMPE manufacturers have demonstrated the feasibility of pyrolysis[TM3.1]-based recycling and are engaged in initiatives to collect and process used ropes.
This study synthesizes insights from scientific literature and direct communication with fibre producers and recyclers to map the potential post-decommissioning value chains for each of the four rope types. We assess the technological readiness levels of mechanical, chemical, physical, and thermal recycling methods specifically for offshore mooring applications[TM4.1]. For each fibre type, we present a Sankey diagram illustrating the flow of materials from decommissioning through intermediate processing steps to the creation of new recycled products. These visualizations aim to support stakeholders in identifying viable recycling pathways and inform future strategies for enhancing circularity in offshore wind systems.
By providing a comprehensive overview of current and emerging recycling technologies, this work contributes to the broader discourse on sustainability in offshore wind infrastructure and highlights opportunities for innovation in fibre rope lifecycle management[I.