Coastal impact induced by a Pelamis wave farm operating in the Portuguese nearshore

Abstract

The objective of the present work is to evaluate the local and coastal impact of a wave farm based on Pelamis convertors that would operate in the Portuguese nearshore. The target area is the coastal environment located north of Peniche. This sector was found in previous studies as representing a significant hot spot from the point of view of the wave energy. An analysis of the wave climate based on historical buoy data was first carried out. This allowed also a preliminary assessment of the electric power expected to be delivered by a Pelamis device in the coastal area targeted. Two farm configurations are considered and simulations with the SWAN spectral model were performed for each case and also for the actual situation when no wave farm operates. The impact in both geographical and spectral spaces was evaluated for various representative wave patterns. Moreover, in order to estimate the influence of the wave farm on the shoreline dynamics, the nearshore circulation was also evaluated using a Surf model. The results show that the presence of a Pelamis based wave farm operating offshore has a strong influence on the wave conditions immediately down wave, but this influence is usually attenuated at the level of the coastline. On the other hand, it appears also that at the surf zone level the longshore current velocity is in relative terms more sensitive to the presence of the wave farms than the significant wave height.