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Renewable energy alternatives to mega hydropower: A case study of Inga 3 for Southern Africa

Renewable energy alternatives to mega hydropower: A case study of Inga 3 for Southern Africa

Site of the Inga 3 dam and larger Grand Inga complex on the Congo river. 
Image credit: International Rivers

Grace Wu, Ana Mileva, and Ranjit Deshmukh used MapRE and a grid simulation model, GridPath, to assess the feasibility and cost-effectiveness of renewable energy alternatives to Inga 3, a 4.8-GW hydropower project on the Congo River, to serve the energy needs of the host country, the Democratic Republic of Congo (DRC), and the main buyer, South Africa. We found that a mix of wind, solar photovoltaics, and some natural gas is more cost-effective than Inga 3 to meet future demand except in scenarios with pessimistic assumptions about wind technology performance. In our scenarios, the effect of Inga 3 deployment on South African power system cost ranged from an increase of ZAR 4300 (US$ 330) million annually to savings of ZAR 1600 (US$ 120) million annually by 2035. But a cost overrun as low as 20%, which is very likely given past empirical data on hydropower dams, made the Inga 3 scenarios more expensive in all sensitivity cases. Including time and cost overruns and losses in transmission from DRC to South Africa made Inga 3 an even less attractive investment. Through a MapRE analysis of the DRC, we found abundant renewable energy potential: 60 GW of solar photovoltaic and 0.6–2.3 GW of wind located close to transmission infrastructure have levelized costs less than US$ 0.07 per kWh, or the anticipated cost of Inga 3 to residential consumers.

The paper is published in Environmental Research Letters 2018 and free to download.