Increasing durability and lowering the overall cost of wave energy converters using Ultra High Performance Concrete

Lowering the overall cost of wave energy converters is a necessity for creating a feasible solution to renewable energy. The design of wave energy converters is in general based on traditional steel design methods. In the design of steel structures subjected to significant dynamical loading and a harsh environment issues such fatigue resistance and durability are of major concern. The welded joints in steel structures significantly reduce the fatigue resistance and give a low utilization ratio of the steel material. Furthermore is coating of all exposed steel surfaces a necessity to secure a sufficient durability of the entire structure. Consequently it will be of great concern to optimize the structural concepts of the wave energy converters and secondly find materials tailored to the harsh environment at sea.

The paper shows that utilizing Ultra High Performance Fibre Reinforced Concrete as primary material in the design of wave energy converters is a feasible and promising solution, which reduce the overall cost of the structure significantly. This will be illustrated by means of a feasibility study carried out on the Wavestar project, where special attention is pointed at the arm and float structure . The arm structure is previously designed as a steel structure, whereas the float has been designed as a light weight glass fibre structure. The new UHPFRC design gives a very beneficial solution that will contribute to the reduction of the manufacturing and the maintenance cost of the Wavestar wave energy converter.