Africa has entered a hydro “super-cycle.” In 2024–2025 the continent added more than 4.5 GW of new hydropower, roughly double 2023’s total, pushing hydro to about 20% of Africa’s electricity generation and bringing long-awaited mega projects to life.
Ethiopia announced the completion of the 5,150 MW Grand Ethiopian Renaissance Dam (GERD) in July 2025; Tanzania’s 2,115 MW Julius Nyerere plant began feeding power in 2024; and Cameroon’s 420 MW Nachtigal project moved toward full commissioning, together redefining how and where power flows across borders.
Why this matters now
- Supply shock for fast-growing grids: New hydro is lifting national baseloads and stabilizing grids that have leaned on costly diesel and fragile coal fleets. Ethiopia’s GERD, now structurally complete, caps more than a decade of investment and anchors plans to export power into East Africa. Tanzania’s Julius Nyerere plant has already synchronized multiple units and is dispatching to the national grid. Cameroon’s Nachtigal is set to meet around a third of Yaoundé–Douala demand once fully online.
- Regional power trade accelerates: New interconnectors and stronger power pools are turning rivers into regional value chains. Kenya began trial wheeling of Ethiopian power on the 500 kV Ethiopia–Kenya line in 2024, a milestone for the East African Power Pool. Southern Africa, meanwhile, is pushing grid upgrades to move more hydro and renewables through the Southern African Power Pool.
- Hydro as a clean flexibility backbone: Beyond electrons, reservoirs and pumped storage provide flexibility to integrate wind and solar. South Africa’s 1,332 MW Ingula pumped storage scheme already plays that role daily and is the template for more storage-led balancing as variable renewables scale.
Also read: Is South Africa’s Energy Transition Doomed to Fail?
What’s actually changing on the ground
Ethiopia: From power deficit to exporter-in-waiting.
With GERD completed in July 2025 and earlier units already generating, Ethiopia is consolidating a hydro-heavy system that includes Gibe III (1,870 MW) and the advancing 2,160 MW Koysha project. The immediate effects: reduced reliance on seasonal diesel, lower marginal generation costs, and capacity to sell surplus through the EAPP once internal transmission bottlenecks ease.
Tanzania: Big baseload shifts industrial plans.
The Julius Nyerere Hydropower Station (often called Stiegler’s Gorge) synchronized its first turbines in late 2023 and began dispatching in 2024, with several units ramping since. For Tanzania, that translates to new headroom for industrial growth, a pathway to displace diesel in isolated grids, and a long-term hedge against fuel price volatility.
Uganda, Cameroon, and the tri-nation Rusumo:
Uganda’s 600 MW Karuma reached full commissioning in 2024, boosting exports during wet seasons. Cameroon’s Nachtigal, one of Africa’s biggest independent hydropower projects, hits commercial phases in 2025. And the 80 MW Rusumo Falls plant started delivering shared power to Burundi, Rwanda, and Tanzania through late 2023–early 2024, demonstrating how moderate-size hydro can unlock equitable regional access.
Gigaprojects still on the horizon promise and peril:
The Democratic Republic of Congo’s Inga 3 and the broader Grand Inga concept (up to 40–50 GW) remain ambitious with recurrent delays and governance risks. Mozambique’s Mphanda Nkuwa (≈1,500 MW) advanced in 2025 with World Bank-backed support toward financing and transmission planning, one of the most bankable “next wave” schemes in Southern Africa.
development co-benefits
- Lower tariffs over time (if grids keep up): Hydropower’s high capex but low operating costs can flatten wholesale prices as assets amortize, if transmission is expanded to move power efficiently. South Africa is the cautionary tale: without about 14,000 km of new high-voltage lines this decade, an estimated 53 GW of potential generation (hydro, wind, solar) stays stranded.
- Jobs and local industry: Large dams create thousands of construction jobs and stimulate cement, steel, and civil works supply chains. Projects like Rusumo have quantifiable local employment and community development impacts baked into results frameworks.
- Climate resilience & irrigation/flood control: Multipurpose reservoirs can steady water supply, buffer floods, and support agriculture, critical as rainfall becomes more erratic. Where paired with floating solar, reservoirs gain extra generation while reducing evaporation losses. Ghana’s Bui reservoir hosts Africa’s largest floating PV to date, pointing to viable hydro-solar hybrids.
The harder truths: risks that must be managed
- Climate variability hits hydro hardest.
The 2023–2024 El Niño drought throttled Lake Kariba, slashing output and forcing widespread blackouts in Zambia and Zimbabwe, an 80% generation drop at one point. The lesson: diversify generation, interconnect across basins, and plan reservoirs with robust hydrology under climate change.
- Social and environmental costs:
Mega dams can displace communities, alter ecosystems, and, especially in tropical settings, emit methane from reservoirs. Design and operation matter: routing, sediment management, minimum environmental flows, credible resettlement, and modern monitoring reduce harm and long-run costs.
- Debt, delivery, and diplomacy:
These projects are capital-intensive and politically sensitive. The Nile Basin’s GERD negotiations underscored how transboundary hydros require durable diplomatic frameworks, data sharing, and adaptive operating rules to build trust over decades, not just during construction.
Also read: Wind power could anchor Africa’s sustainable energy future
What to watch next
- Full commercial ramp-up at GERD, Nyerere, Nachtigal: How quickly do these plants hit dependable capacity, and how much is exported versus used domestically?
- Financing closes for Mphanda Nkuwa and transmission links to Southern African buyers, including South Africa and Mozambique’s industrial users.
- Grid build-out speed in South Africa and East Africa: Will the promised 14,000 km of lines materialize fast enough to carry new hydro and renewables, and will East African Power Pool trading volumes scale after the Ethiopia–Kenya link goes fully commercial?
- Hydro-solar hybrids & storage: Expect more floating PV on reservoirs and new pumped-storage proposals as countries chase flexibility to smooth rainy-dry season swings.
