Southerly winds increase the electricity generated by solar photovoltaic systems

Abstract

The urgent need to decarbonise energy supplies has prompted exponential growth of solar photovoltaic (PV) systems across the world. As the penetration of renewable energy sources increases, the need to accurately forecast electricity output heightens to ensure efficient energy system operation. While exposure to high temperatures and moisture are known to significantly reduce PV panel efficiency, the effects of wind on both PV panel temperature and electricity output are poorly resolved. Here, meteorological and PV panel production data from Westmill Solar Park, Oxfordshire, were examined to determine the influence of wind, cloud, ambient temperature and relative humidity. We found that, after solar radiation, relative humidity and cloud cover were the dominant controls of PV electricity output; increases in relative humidity and cloud cover were associated with decreased electricity outputs. However, when all other variables were held constant, the mean electricity generated under southerly winds was 20.4 – 42.9% greater than under northerly winds, with the difference greater at higher electricity outputs and attributable to differences in surface cooling capabilities caused by the PV array asymmetry. This finding suggests that PV electricity output predictions could be improved by incorporating wind direction into computer models. Moreover, there is potential to modify solar park design and deployment location to capitalise on wind benefits, especially in areas where panel temperatures are a leading cause of efficiency loss. Ensuring deployments are optimised for site environmental conditions could boost electricity outputs, and therefore profitability, with implications for system viability in post-subsidy markets.