Wave resource characterization and co-location with offshore wind in the Irish Sea

One barrier affecting progress in the wave energy sector is detailed knowledge of the spatiotemporal distribution of waves in shelf sea regions, including their inter- and intra-annual variability. Here, a recent decade (2012-2021) of waves is simulated at high-resolution in the Irish Sea - a region with much offshore energy infrastructure. The spectral wave model SWAN is forced with ERA5 wind fields. There is a strong seasonal cycle in wave height and power. In all months except for July, large waves (significant wave height greater than 5 m) can penetrate into the northern part of the Irish Sea, but the most energetic region is the Celtic Sea, where monthly mean wave power exceeds 30 kW/m in December. In this region, wave power strongly correlates with the North Atlantic Oscillation (NAO) from September to March. To investigate the potential for co-location, i.e. to reduce costs through shared infrastructure, wave and wind power were compared at a leased floating wind site in the Celtic Sea. Over the simulated decade, r^2 ~ 0.5, demonstrating modest potential for co-location of wind and wave energy technologies in this part of the Irish Sea - considerably less favourable than other sites in the North Atlantic that experience greater swell.