Climate warming and large-scale climate variability are contributing to measurable changes in lightning activity across Southern Africa with direct implications for high-voltage transmission reliability, according to new research by Renier van Rooyen of Eskom Research, Testing and Development.
The study, presented at CIGRE Southern Africa 2025, analyses lightning exposure along the 533 kV Apollo-Songo HVDC transmission corridor between South Africa and Zambia using high-resolution lightning stroke data from January 2013 to March 2025. It builds on earlier work conducted on the Alpha-Beta 765 kV AC corridor and applies the same methodological framework to a different, climatically diverse transmission route.
Results show a strong positive correlation between surface temperature and lightning activity with a Pearson correlation coefficient of r = 0,90 confirming temperature as a primary driver of convective conditions leading to increased lightning stroke density. Convective available potential energy CAPE was also found to be a strong predictor of lightning variability, reinforcing the role of atmospheric instability in lightning generation.
