The development of ocean energy conversion systems places more severe requirements on materials than similar land-based structures such as wind turbines. Intervention and maintenance at sea are more costly so long term durability must be guaranteed if ocean energy supply is to be economically viable. Composite materials offer many advantages over metallic structures, with respect to ease of fabrication of complex profiles and light weight for installation, and many composite marine structures have shown remarkable longevity. Nevertheless material selection is critical. The choice of glass is important if stress corrosion is to be avoided, while resin chemistry must be optimized to limit matrix damage. Fibre/matrix interface properties are also critical when composites are immersed for long periods and the know-how of both fibre and resin producers is essential to optimize these. This paper presents an overview of the use of composites in marine and ocean energy applications, then first results are presented from a collaborative study involving 3 major fibre and resin producers and 2 research groups, aiming to characterize and model the long term behaviour of glass reinforced epoxy composites in sea water.
