Coastal response to wave energy converter arrays: A semi-analytical model for control of nearshore currents and beach morphology

A semi-analytical method much faster than typical computational and experimental methods is developed to quantify how wave energy converter arrays (“wave farms”) affect nearshore currents and beach erosion when they modify ocean waves, providing a semi-analytical initial design tool for evaluating coastal impacts of wave farms. The method integrates an existing semi-analytical wave farm model with a nearshore current model; the latter is a rip current model, modified to tackle the wave field produced by wave energy converter arrays. The method is validated against a classic example and compared to results from numerical simulations and wave basin experiments, for an array of 16 oscillating water column devices. The method is then implemented optimise the 16-device array to increase its ability to protect the beach. It is found that the arrays most effective for beach protection also perform well in energy generation, with outputs close to the optimal-power arrays. This suggests that prioritising beach protection does not substantially compromise energy generation performance. • Fast semi-analytical model for quantifying beach impacts due to offshore wave farms. • Enables wave farm layout optimisation on an entry-level laptop computer. • Combines a nearshore current model, a wave model, and a beach erosion model. • Model outputs are compared with existing numerical and experimental results. • Beach protection does not substantially compromise energy generation performance.