This paper presents a statistical Extreme Value Analysis (EVA) methodology to evaluate the design survivability condition of a Wave Energy Converter (WEC). The technique is applied to the Oyster® WEC design which is being developed by Aquamarine Power Ltd. (APL) but can be easily modified to investigate other technologies that have different operational philosophies. The approach presented considers the extreme statistics of both the incident wave climate at the device location and the complex dynamic response of the WEC in such conditions. This give a more robust evaluation of the WECs survivability condition than a more traditional single design wave approach.
An Extreme Value Analysis (EVA) technique is presented in this paper to evaluate the loading survivability condition of a Wave Energy Converter WEC. Determining the maximum expected load experienced by a WEC during its operational lifetime is of paramount importance to the design process, in particular to the design of the foundation and/or mooring system. Thorough and consistent EVA can reduce/remove the implementation of large safety factors to a WEC design load condition which can have significant cost benefits. Extreme loads experienced by a WEC are not only dependent on the nature of the wave climate within which it is operating but also on the phase relationship between each incident wave and the WECs dynamic response. These unique features make it necessary to develop a custom EVA technique with specific application to WECs. A possible hazard of developing an EVA methodology is that it relies heavily on novel analysis techniques. Consequently large safety factors are often applied to the design load undermining the goal of using EVA. The ethos adopted in this paper is to apply well accepted techniques to minimise uncertainty and hence the subsequent use of excessive safety factors connected with the modelling approach itself.
