Steel-concrete connections for floating wave energy converters

In order to make wave power technologies competitive within the overall energy market, there needs to be significant reductions in the levelised cost of energy (LCoE). One area for potential cost reduction is the use of cheaper materials that are suitable for use in the harsh marine environment, such as reinforced concrete, which gives good corrosion and fatigue properties while providing excellent strength and stiffness at low unit cost. Concrete has the potential to be used for a wide range of wave energy device configurations, however in general use has been limited to nearshore fixed bottom wave energy converters. To date, no dynamic floating wave energy devices have successfully utilised reinforced concrete as structural material, mainly due to the uncertainty surrounding the behaviour of critical dynamic connections between concrete sections and other materials. This paper explores the main issues surrounding steel-concrete connections for floating wave energy converters, providing a review of available design options and standards and assessing the applicability of these to WECs. A methodology is proposed for the evaluation of connection options, and a case study of the Squid 12S floating WEC (developed by Albatern) is presented.