Objective & Background
Decarbonisation of global energy production in the future implies an increased role for intermittent renewable energy sources. Wind energy will continue to make a very significant contribution, but solar PV capacity is expected to grow substantially in the coming years. A better understanding of the spatio-temporal patterns of variability in the solar energy resource is increasingly urgent, particularly in the context of its links to large-scale atmospheric teleconnection patterns such as the North Atlantic Oscillation (NAO), the East Atlantic (EA) and Scandinavian (SCAND) patterns.
This work focuses on the spatial relationships between the solar short-wave (SW) radiation across Ireland and Britain, and the dominant Euro-Atlantic atmospheric pressure teleconnections, such as the NAO, EA and SCAND patterns.
Multiple observational and gridded solar irradiance reanalysis datasets (global: ERA-Interim, MERRA-2, with spatial resolution of ~78 and 50 km, respectively; regional: MÉRA, 2.5 km) covering several decades of solar irradiance data were compared with the variance indices of the atmospheric patterns over the same time-period (1982-2015), for the winter season (December to February).
In addition, to evaluate the solar variability in terms of power metrics, we take advantage of the high-resolution solar irradiance data to convert it to solar power generated.
The zonal (west-east) seesaw behaviour in the correlation pattern between the winter North Atlantic Oscillation (NAO) index and SW radiation across the UK is more complex than reported previously , and it involves several zonal changes in the NAO-SW correlations (multiple ‘seesaws’) across both Ireland and the UK mainland. We interpret this as being the result of the interaction between the predominant moisture-bearing airflows, controlled by large-scale atmospheric patterns, and local topography which, through uplift and rainout mechanisms, ends up producing different irradiance conditions between the windward and the leeward side of hills and mountains. This process, which also contributes to producing significant differences between solar resources on the west and east side of both Ireland and Britain can be explored for solar-solar or solar-wind energy generation balancing on a range of spatial scales.