Abstract
Ocean wave energy remains pre-commercial after four decades, with under 3 megawatts deployed against some 80 gigawatts of offshore wind. Cost and efficiency explanations are incomplete: structural and station-keeping failure recur in documented wave energy converter (WEC) terminations. This review examines WEC structural integrity over 2016–2026 and Preferred Reporting Items for Systematic reviews and Meta-Analyses asks what the sector can learn from offshore wind. The methodology is two-part. Part A is a Preferred Reporting Items for Systematic reviews and Meta-Analyses 2020 systematic review of the WEC literature (Scopus, Web of Science, IEEE Xplore) plus grey literature; Part B is a purposive review of five pre-defined offshore wind practice areas. Together these draw on 150 references (117 in-window 2016–2026; 33 foundational). Addressing RQ1, WEC failures parallel early offshore wind in three respects: subsystem failure dominates primary-structure failure; the gap between codified and observed design loads persists; and condition monitoring is now the operational response to residual risk. They diverge in two critical ways: offshore wind can feather its rotor into a low-load survival state, whereas WECs must use active, high-energy survival configurations with their own failure modes; and offshore wind has the fleet scale that underpins reliability benchmarking. Addressing RQ2, transferability against four criteria (physical analogy, data availability, regulatory maturity, economic feasibility) shows that reliability benchmarking, standards content, and Supervisory Control and Data Acquisition-based monitoring transfer only partially, while vibration monitoring and coupled analysis transfer fully. Digital-twin methodology transfers asymmetrically: physics-based models suit single-prototype validation, whereas data-driven monitoring is constrained by the absence of a WEC fleet. We argue for a compressed rather than replicated trajectory and identify four priority research directions.