From shallow to deep water: a review of scour and its impacts on floating wind turbines

Due to the growing demand for renewable energy, offshore wind turbines are attracting increasing attention. Owing to limited space in nearshore waters, expansion into deep-sea areas has become an inevitable trend. However, offshore fixed-bottom wind turbines and deep-sea floating offshore wind turbines (FOWTs) differ fundamentally in their foundation systems. Existing insights indicate that the wind turbines are highly susceptible to scour induced by waves and currents. While substantial progress has been made in understanding scour and its impact on offshore wind turbines with monopile, jacket, and bucket foundations, scour mechanisms in deep-sea environments remain poorly understood due to the lack of field data and operational experience. FOWTs represent a key technology in harnessing deep-sea wind energy; however, their anchor foundations may face significant challenges from scour induced by undercurrents, including gravity currents and contour currents. This review systematically examines the potential scour mechanisms and performance evolution of FOWT anchors. Through integrated analysis of scour processes, sedimentary system interactions, and flume experiments, this study highlights the susceptibility of various anchor types to undercurrent-induced scour. This research highlights potential scour-related risks and emphasises the need for innovative design optimisations to improve anchor stability in dynamic deep-sea environments.