WEC Design Based on Refined Mean Annual Energy Production for the Israeli Mediterranean Coast

Abstract

Using the Israeli Mediterranean as an example, we address the impact of resource variability and device survivability on the design of floating-body wave-energy converters (WECs). Employing a simplified heaving cylinder as a prototypical WEC, several device sizes, corresponding to the most frequently encountered and most energetic sea states in the Israeli Mediterranean, are investigated. The mean annual energy production is calculated based on the scatter-diagram/power-matrix approach. Subsequently, a measure for significant device motions under irregular sea-states akin to the spectral significant wave-height is developed, and cutoffs to regular operation are explored from the perspective of these significant displacements. The impact of this WEC downtime is captured in a refinement of mean annual energy production, which consists of supplementing the scatter-diagram/power-matrix calculations by a Boolean displacement matrix. In the Israeli Mediterranean, where most of the annual incident wave power comes in infrequent winter storms, larger WECs outperform smaller WECs by a greater margin when downtime is taken into account. Analogous displacement cutoffs for refining calculations of mean annual energy production may inform WEC design for other sites.