A numerical modelling investigation of the wave resource at Ireland's wave energy test sites

Ocean wave energy harvesting research and development has grown in recent years and wave energy conversion to electricity using wave energy converters (WECs) on a commercial scale is also becoming more realistic. This research is concerned with characterising wave energy resources, investigating resource scalability and assessing the impacts of wave farms. The research presents a detailed wave resource assessment methodology, development of a suite of nested local scale wave models using Simulating Waves Nearshore (SWAN) wave model, determination of scaling approaches for upscaling from benign test sites to full scale deployment sites and analysis of the effects of WEC arrays on the nearshore wave climate. A detailed methodology for wave resource assessment has been developed for identifying operational, high and extreme wave conditions. The methodology was applied at three wave energy sites on the West coast of Ireland – (i) the 1/4-scale Galway Bay Test Site (GBTS), (ii) the full-scale Atlantic Marine Energy Test Site (AMETS) and (iii) the Westwave site. Two validated nested local wave models were developed and simulated for 12-years (2004-2015) to conduct wave resource assessment. The 12-year annual mean power calculated for the sites were 68 kW/m and 57 kW/m at Berth A at Berth B, respectively, at AMETS, 3kW/m at GBTS and 50kW/m at Westwave. Three scaling approaches were analysed to identify the appropriate scale ratios to be used to upscale wave conditions at GBTS to AMETS. The distribution fittings method was found to be the most accurate method to upscale GBTS to AMETS and Westwave. The scaling result shows GBTS is not 1/4-scale proportionate to AMETS or Westwave as previously assumed. Finally, an analysis of WEC array impacts on the nearshore wave climate involved the determination of an appropriate transmission coefficient (Ct) from a computational fluid dynamic (CFD) and WEC arrays implementation using SWAN. The Ct value from the CFD model was used in SWAN to represent WEC arrays. WEC array performance and device layouts and spacing was investigated and three WEC arrays scenarios have been examined to assess their impact on the wave climate at the nearshore area of the Westwave site