Rethinking energy planning to mitigate the impacts of African hydropower

Around 100 GW of new hydropower projects have been proposed in continental Africa to contribute to meeting future energy demand. Yet, the future expansion of hydropower on the continent faces obstacles due to the impacts of dams on rivers, greenhouse gas emissions from reservoirs and increasingly competitive alternative renewable electricity technologies. Here we propose an integrated approach to include these considerations in energy planning. Compared with planning for least-cost energy systems, capacity expansion strategies balancing environmental and techno-economic objectives increase electricity prices and total discounted costs by at most 1.4% and 0.2%, respectively, while reducing impacts on annual hydropower emissions and river fragmentation by at least 50%. Our results demonstrate that refining techno-economic analysis in light of global and local environmental objectives can help policymakers reduce the river fragmentation and greenhouse gas emissions associated with hydropower development at marginal increases in energy costs.Meeting future energy demands in Africa will require expanded hydropower capacity, but the dams' impacts on rivers, their emissions and alternative energy options call for careful planning. This study performs multi-objective energy system modelling for more sustainable dam expansion from the present to 2050.