6th International Conference Energy & Meteorology: Abstract Submission

Objective and background

In Sub-Saharan Africa, 160 million grid-connected consumers live in countries where hydropower accounts for over 50% of total power generation. The IEA forecasts that during the 2020s hydropower capacity in SSA will increase at a rate of 6% per year (and thus be the fastest-growing technology in terms of capacity additions), and reach 95 GW by 2040. This will determine an increasing reliance on hydropower for power supply. The figure below shows the evolution of hydropower generation over total generation in hydropower-dependent countries.

A vivid debate is taking place in the academic literature and in the decision-making spheres on how anthropogenic climate change - and thus changing precipitation and evaporation patterns and more frequent and intense extremes - but also additional demographic and socio-economic stressors will affect hydropower reliability. However, the lack of a systematic review building on a robust theoretical framework, analyzing relevant data to provide evidence and support findings, and focusing on the specific issue of hydropower dependency in SSA was witnessed.

Methods

In this context, (i) a robust framework  to highlight the interdependencies  between  hydropower  generation,  water  availability,  and  climate  change is designed,  (ii) the state-of-the art literature on the projected climate impacts on hydropower is reviewed, and (iii) supporting data evidence on hydropower capacity factors, drought events (using the SPEI,  Standardized Precipitation-Evaporation Index), reservoir water levels (with TOPEX satellite measurements), and future climate projections (RCPs CMIP-5 average) is provided.

Principal Findings

Results show agreement over the fact that East Africa's hydropower output could positively benefit from a warmer climate and West and Southern Africa would suffer negative impacts, while Central Africa presents more uncertainty. However, even where absolute rainfall increases are expected, more frequent and intense extremes are predicted, thus increasing the likelihood of temporary disruptions. In general, years with higher local values of the SPEI index have been associated with higher water basin levels (although high inter-basin heterogeneity is observed, with negative or null relationships in some water bodies), and in turn lower water levels generally implied lower hydropower capacity factors in the vast majority of the basins and countries considered. 

Discussion

Results therefore suggest that current and future strategic energy decisions will have a major impact on the resilience of energy systems in SSA. Countries - in particular those highly reliant on hydropower - should plan the mix of capacity additions with a long-term outlook and increase adaptive capacity under extremes. Policymakers should give the necessary importance to the potential impact of climate change on existing and planned hydropower schemes, and exploit complementarities between different RE sources, including solar PV, wind, and hydropower, but also with natural gas, so as to guarantee a low-carbon and secure power provision. A missed diversification might hinder economic growth prospects.