The impact of sea breezes on offshore wind energy resources in Australia

Abstract. Future projected increases in offshore wind energy in Australia means that it is important to understand variability in wind resources. This includes the potential diurnal variation of wind, and its co-variability with known diurnal variations of energy demand and supply. A key mechanism for diurnal variations in coastal near-surface winds is the sea breeze, which is driven by differential land-sea surface heating during the day. Here, a new dataset characterising the sea breeze as a frontal object, derived from a km-scale reanalysis, is used to analyse the impact of the sea breeze on diurnal variations of wind energy resources over 1979–2024. This analysis is performed over eight potential offshore wind areas in southeastern and southwestern Australia during the summer. On days with a sea breeze object, there tends to be more potential wind energy resources available in coastal and offshore wind areas during the afternoon, although there may also be late-morning lulls due to the sea breeze opposing the existing prevailing winds. In addition, days with a sea breeze correspond to higher regional energy demand on average, due to warmer air temperatures over the land, while the peak in potential wind energy occurs with similar timing to peak demand. Finally, due to the role of the prevailing wind direction in sea breeze formation, there is an anti-correlation in occurrences between opposite-facing coastlines. These results have implications for energy system planning and suggest that offshore wind farm development on a diverse set of coastlines should be encouraged in Australia.