This policy brief is based on previous research led by Professor Declan Conway at the London School of Economics and Political Science, in collaboration with researchers at University College London, the University of Pretoria and the University of East Anglia. Recent disruption to electricity supply in eastern and southern Africa has highlighted the challenges of chronic electricity scarcity. To increase capacity, both regions have a preference for hydropower. Most of the planned new plants will be dependent on areas with similar rainfall patterns and thus multiple plants will experience climate-related disruption concurrently, with considerable impacts for socioeconomic development. Using analysis of the spatial distribution of rainfall in the regions, as well as climate models and research into the impacts of the 2015/16 El Niño event, this policy brief explains the increasing risk of concurrent climate-related disruption to hydropower and provides policy recommendations for overcoming the challenges.