Sea state characterisation of the test site of an offshore wave energy plant

The Archimedes Wave Swing (AWS) pilot plant, rated at 2 MW, was tested offshore at Povoa de Varzim in northern Portugal in 2004, gathering a large team of engineers and scientists. The Mechanical Engineering Department of Instituto Superior Tecnico was involved, following previous work done for the project. The present paper describes one of the studies conducted. It aims to characterise the sea state at the actual location of the pilot plant using the available pressure sensors. Two approaches were performed: a first one purely based in linear wave theory, neglecting the presence of the device, and a second one, based on the results from a Boundary Element Method (BEM) code named AQUADYN, originally developed at Ecole Centrale de Nantes (France), which allowed a detailed quantification of the effects of the presence of the plant on the wave profile directly above it. Comparisons with a Datawell Waverider buoy located at a certain distance from the plant also played an important role in the current study. (C) 2006 Elsevier Ltd. All rights reserved.