Wave energy converter geometry for coastal flooding mitigation

Rafael J Bergillos; Cristobal Rodriguez-Delgado; James Allen; Gregorio Iglesias

doi:10.1016/j.scitotenv.2019.03.022

Wave energy converter geometry for coastal flooding mitigation

Sci Total Environ. 2019 Jun 10:668:1232-1241. doi: 10.1016/j.scitotenv.2019.03.022. Epub 2019 Mar 6.

Authors

Rafael J Bergillos¹, Cristobal Rodriguez-Delgado², James Allen³, Gregorio Iglesias⁴

Affiliations

¹ Hydraulic Engineering Area, Department of Agronomy, University of Córdoba, Rabanales Campus, Leonardo Da Vinci Building, Córdoba 14071, Spain. Electronic address: rafael.bergillos@uco.es.
² School of Engineering, University of Plymouth, Plymouth PL4 8AA, UK; PROES Consultores, Calle San Germán 39, Madrid 28020, Spain.
³ School of Engineering, University of Plymouth, Plymouth PL4 8AA, UK.
⁴ MaREI, Environmental Research Institute & School of Engineering, University College Cork, College Road, Cork, Ireland; School of Engineering, University of Plymouth, Plymouth PL4 8AA, UK.

PMID: 31018463
DOI: 10.1016/j.scitotenv.2019.03.022

Abstract

Wave farms, i.e., arrays of wave energy converters (WECs), have been proposed to fulfil the dual function of carbon-free energy generation and coastal protection. The objective of this work is to investigate, for the first time, how the coastal protection performance against flooding is affected by WEC geometry. This is done by means of a case study with WaveCat WECs (floating, overtopping WECs) deployed off the Playa Granada beach (Spain). To this end, two models of WaveCat WECs with different geometries are tested in a laboratory tank at a 1:30 scale under low-, mid- and high-energy sea states representative of the wave conditions of Playa Granada. The geometries differed in the angle between the twin hulls (wedge angle) of WaveCat: 30° and 60°. The reflection and transmission coefficients thus obtained are used in a coupled numerical modelling approach, combining wave and coastal processes models (SWAN and XBeach-G, respectively). We find that WECs with an angle of 60° provide more (less) protection for long (short) wave periods in terms of reductions in wave height and run-up on the beach. As for the flooded dry beach areas, they are generally smaller for WECs with 60°, with only some exceptions under mild conditions. Thus, considering that beach inundation usually occurs under high-energy, storm conditions, we conclude that the wave farm composed by WECs with a wedge angle of 60° is more efficient against coastal flooding.

Keywords: Coastal flooding; Device geometry; Laboratory tests; Numerical models; Wave farm.