Assessment of Sensitivity Analysis Methods of Different Complexity for Offshore Wind Turbines

Sensitivity analyses (SA), being used to identify the most influential inputs of simulation models, are still rarely conducted for offshore wind turbines (OWTs). If SA are performed, in most cases, no reasons for the choice of the method are given and the selection is based on expert knowledge only. Objective criteria are not applied. Frequently, simplified SA are utilized, e.g. one-at-a-time analyses, although it is known that these approaches are not suitable for non-linear or stochastic systems. Sophisticated SA, like variance-based methods, are time-consuming and limited suitable for OWT models. As a consequence, here, the performance of various SA methods of different complexity in the context of structural analyses of OWTs is investigated. The analyzed methods range from simple testing of parameter constellations, to elementary effects and meta-model-based approaches, all the way to variance-based approaches. Objective recommendations with regard to the most suitable SA methods for OWT analyses based on the two criteria, accuracy and computing time, are given. Results show that neither plain linear SA (not selecting the right probabilistic subset) nor variance-based approaches (being computational inefficient) are the best choice, but meta-model-based approaches represent the recommended compromise. Furthermore, challenges of SA for stochastic systems are highlighted.