Analysing the Relationship Between Weather Systems and Wind Resource Potential and Variability in South Africa

Many countries are employing variable renewable energy (VRE) sources, especially wind, towards the fulfillment of their decarbonization goals. Major challenges in the power system are however emerging as a result of the variability caused by these wind energy sources. It has been shown that at time scales of hours to days such variability is mainly caused by large-scale atmospheric circulation patterns. Quantification of the relationship between atmospheric circulation and wind power variability is, as such, an ongoing area of research. In the South African context, fairly little research has been done in this field, despite its implications for network stability. Accordingly, this study aims to investigate and quantify wind resource potential and variability associated with a set of classified atmospheric states representative of synoptic-scale circulation over South Africa. Weather classification methods were reviewed, and it was established that self-organizing maps (SOMs) are well-suited to be used in this study to classify the atmospheric states. It was found that extratropical cyclone weather systems are associated with the greatest resource potential and variability. It is accordingly concluded that the passage of such weather systems should be considered in the integration of wind generation into the power system. It is anticipated that a systematic assessment of the main weather regimes responsible for fluctuations in wind and other VRE resources would be valuable to improve VRE generation forecasts and inform generator siting.