Coastal defence using wave farms : The role of farm - to - coast distance

The location of a wave farm, and, in particular, its distance to the coast is one of the key aspects in a wave energy project. In the selection of the location a number of variables are typically taken into account, from the wave resource to the maintenance or infrastructure costs; however, the effects of the farm on the coast, which can be instrumental in mitigating storm-induced erosion and thus contribute to coastal defence, are seldom, if ever, considered. This is down partly to the inexistence of an ad hoc methodology. In this context, the objective of this work is to examine the influence of the farm-to-coast distance through a sensitivity analysis focused on Perranporth Beach (SW England). The impacts on the wave conditions and the beach morphology of a wave farm are examined in four scenarios, corresponding to three different distances from the coastline plus the baseline. A high-resolution suite of numerical models is used to study the response of the beach under different storm conditions. The results show that a wave farm closest to the beach would offer a higher degree of coastal protection than the other two scenarios, with a reduction of up to 20% in the beach erosion. The downside of this enhanced coastal protection is that the overall wave resource available at this location would be slightly smaller (approx. 10 %) than in the case of the wave farm furthest from the coast. Beyond the detailed quantitative results, the general conclusion that can be drawn is that the farm-to-coast distance is a critical variable in *Corresponding author; e-mail: [email protected]; tel.: +44.(0)7583 544041.