Future hydropower operations in the Zambezi River Basin: Climate impacts and adaptation capacity

Southern Africa could experience major hydrological changes in coming decades, bringing drastic changes to hydropower. Focusing on four large hydropower dams in the Kafue and Zambezi rivers (Itezhi-Tezhi, Kafue Gorge, Kariba, and Cahora Bassa), this study analyzed how river discharge and hydropower could be affected by future climate change and water use. Future climate change could affect reservoir levels by decreasing water inflows and by increasing evaporation. Results showed a decrease in median annual water levels for all reservoirs, with largest changes expected at Itezhi-Tezhi (-1.3 to -3.3m), followed by Cahora Bassa (-0.8 to -2.8m), Kariba (-0.2 to -0.9) and Kafue Gorge (0.1-0.2 m). Flows downstream of dams show a consistent negative trend, with mean annual flow changes of -30 to -49% at the furthest downstream gauge. The combined reduction in water levels and flows could result in decreases on average annual hydropower generation and increases in interannual variability; annual generation could decrease from 5989 to 2366-4307 Gwh/yr (-61 to -28%) at Kariba, from 675 to 331-537 Gwh/yr (-51 to -21%) at Itezhi-Tezhi, and from 17687 to 12952-16160 Gwh/yr (-9 to -27%) at Cahora Bassa. Reservoir operation optimization could marginally offset the projected changes in hydropower generation for Kariba and Cahora Bassa, but overall energy generation reduction is expected to be much greater. Given these negative projections, it is becoming even more critical to adapt and coordinate reservoir operations to best cope with the expected challenging future in this important river basin.

ARIAS Mauricio;  FARINOSI Fabio;  HUGHES Denis; 

2022-08-19

WILEY

JRC124430

1535-1459 (online),   

https://onlinelibrary.wiley.com/doi/epdf/10.1002/rra.3958,    https://publications.jrc.ec.europa.eu/repository/handle/JRC124430,   

10.1002/rra.3958 (online),