Wave energy converters with rigid hull encapsulation: A review

Ocean wave energy has a great potential in mitigating energy and sustainability crises of the 21st century. The lack of mature and cost-competitive wave energy converter (WEC) technologies, however, has become a major roadblock for WEC products entering the marketplace. A harsh ocean environment, which includes extreme waves, strong biological activities, and chemical transformations, adds to the maintenance cost and survivability of WECs. Among various types of WEC technologies, WECs with rigid hull encapsulation offer an effective means against such environmental challenges. Using a sole rigid hull to encapsulate an entire WEC except for power cables and mooring lines, the hull creates a robust and watertight protection to the WEC and permits a relatively simple WEC design. This review provides a comprehensive analysis on existing WEC technologies employing such rigid hull encapsulation. The review topics cover technologies and working principles, power generation mechanisms, control strategies, mooring schemes, experimental studies, as well as technology readiness levels and development trends. Some future research considerations are suggested in addressing some common chal-lenges. As an effort to present a global view of this particular type of WECs, the review is expected to benefit future WEC developments employing rigid hull encapsulation.