"The expected changes in precipitation levels and patterns are uncertain, however. Different climate models and scenarios offer a mixed picture of how the future might unfold, particularly over central and southwestern Africa. Still, there is consensus that extreme hydrological events will increase throughout the continent with climate change. This will make power systems less reliable, unless there’s proper planning in place."
Several countries are more at risk than others because they depend largely, or entirely, on hydropower generation and have few back-up options available. These include the Democratic Republic of Congo, Ethiopia, Uganda, Zambia, Mozambique and Sierra Leone. Some might even increase their dependency on hydropower.
Climate change will affect hydropower – African countries must be prepared (theconversation.com)
"Meanwhile, in the African region, hydropower is the largest source of renewable energy on the continent, contributing almost one-quarter of the total electricity generation in sub-Saharan Africa. Several countries are more at risk than when it comes to a decrease in hydropower generation due to climate change, as they have few alternative energy sources available. These include the Democratic Republic of Congo, Ethiopia, Uganda, Zambia, Mozambique and Sierra Leone. This demonstrates the severe need for the development of a more diverse energy mix across the continent.
There is significant potential to develop more hydropower in several regions of the world, particularly in Africa. However, the worsening effects of climate change are threatening the previously reliable renewable energy source. If droughts happen more frequently, those countries affected will have a reduced hydropower capacity, meaning they may come to rely on alternative energy sources or energy imports from other countries.
The Hydropower Industry Is Facing an Existential Threat | OilPrice.com
"The projected decrease in the capacity factor in the Congo and Zambezi Basins is alarming, given the significant role of hydropower in this subregion. Some countries already have difficulties in coping with the current level of dryness. For instance, the power supply in Zambia, where more than 80% of electricity comes from hydro (IEA, 2019b), has been significantly affected by declining water availability due to a shorter rainy season and more frequent droughts (Onishi, 2016). In February 2016, the water level of the Kariba Dam, one of the biggest electricity sources for Zambia and Zimbabwe, dropped to near-record lows, 12%, prompting blackouts, power rationing, and a slow-down of economic development in some places (IHA, 2017). The disruption occurred again in August 2019, and the Kariba station needed to cut output and impose daily blackouts (Bloomberg, 2019). The projected changes in rainfall patterns can severely threaten the electricity security of Zambia and Zimbabwe, given their heavy reliance on electricity supply from the Kariba station."
Climate impacts on African hydropower – Climate Impacts on African Hydropower – Analysis - IEA