Current status and perspectives on shared moorings for offshore floating renewable energy systems: A review

Floating renewable energy systems, including offshore wind turbines (FOWTs) and wave energy converters (WECs), are increasingly recognised as pivotal for achieving decarbonisation targets. However, the high cost of station-keeping systems remains a key barrier to large-scale deployment. Shared mooring strategies, comprising shared lines and shared anchors, offer promising pathways for reducing both capital and operational expenditures. This review presents a comprehensive analysis of the current state-of-the-art in shared mooring systems for floating renewable technologies. The manuscript is structured to (i) introduce the mooring design problem in the context of renewable energy applications; (ii) categorise and critically assess all peer-reviewed publications to date on shared mooring systems for both wind and wave energy; and (iii) identify key modelling approaches, limitations, and emerging trends. Emphasis is placed on dynamic simulation techniques, hydrodynamic loading, and the often-neglected role of anchors and soil-structure interaction. Furthermore, the review highlights the divergence in modelling fidelity across studies and the implications for reliability and cost. Particular attention is given to recent experimental efforts and the Hywind Tampen project, the first industrial-scale wind farm to implement shared anchors. The findings underscore the lack of standardised methodologies and the pressing need for integrated design frameworks that account for nonlinearities, multidirectional loading, and site-specific constraints. Ultimately, this work aims to bridge gaps in current practice, offering a technical foundation for future research and development in cost-effective and scalable mooring solutions for floating renewable energy systems.