Decadal wave power variability form satellite altimetry in Ireland

Ireland is the first landmass between the northeast Atlantic Ocean and Europe; its geographical location endows it with high energy potential in the ocean. At present, around 40% of the energy in Ireland is generated by renewable technologies, the majority of which is produced by onshore wind turbines. However, given the marine energy potential, the integration of wave energy converters into the future energy mix is a plausible proposition. This integration would result in a more stable energy mix, which is not reliant upon a single renewable resource. This study aims to analyse the wave power potential in Ireland by employing long-term satellite altimeter and weather buoy observations. Satellite altimeters offer long-term measurements, and cover a broader area compared to weather buoys. Data spanning from 1995 until 2024 is employed, encompassing a total of 30-years. This timeframe is particularly pertinent in the context of the analysis, as it encompasses the projected lifespan of the wave energy converters to be potentially installed. The goal is to assess whether decadal variations on the available wave power would affect the devices’ performance. To this end, wave power variation maps are generated. As satellite altimeters do not measure wave period, a regression following the method proposed by Gommenginger et. al. (2003) is employed to estimate the zero-crossing wave period by relating the significant wave height and the back-scatter coefficient measured by the altimeters, with Irish moored buoy observations. The wave energy period is obtained from wave period ratio maps created from results by Haoyu Jiang et. al. (2022); ultimately wave power is calculated assuming deep water and panchromatic seas. Decadal variations are calculated with via Theil-Sen approach, after removing the lag-1 autocorrelation, and the statistical significance its evaluated by means of the Mann Kendall test.