Cahora Bassa’s €1.2bn Overhaul and the €950m Question

A €1.2 billion price tag sits at the centre of Hidroeléctrica de Cahora Bassa’s decade-long rehabilitation programme. Confirmed external development finance covers roughly €247 million of it. The first question a commercially minded reader should ask is not what the money buys, but who funds the remaining gap, and what that gap reveals about how this asset is being priced.

This is not a routine equipment refresh. The South Power Station at Cahora Bassa holds 2,075 MW of installed capacity, delivered 12,351 GWh of electricity in 2024, and sends 66% of that output to South Africa’s Eskom. A ten-year overhaul of a facility on that scale is a regional energy security event. The timing sharpens the point: HCB’s executive board has described the drought affecting the reservoir since 2023 as the worst in 40 years.

What follows here is a practical frame for assessing the programme before forming a view on it. You will finish with a structured way to judge the CAPEX Vital programme’s financing adequacy, its execution risk, and its consequences for Southern African power supply through the 2030s.

A €1.2 billion commitment built on €247 million in confirmed financing

Start with the three confirmed facilities, because they are where the arithmetic gets interesting. The French Development Agency (AFD) signed a €100 million non-sovereign concessional loan in December 2022, carrying a 15-year maturity. The African Development Bank (AfDB) approved a package of up to €125 million on 29 November 2022, comprising up to €100 million from AfDB itself plus up to €25 million from the Africa Growing Together Fund. Alongside these, AFD administers a delegated European Union grant of approximately €22.1 million.

Add those up and you reach roughly €247 million. Against a €1.2 billion programme, that leaves close to €950 million unaccounted for by confirmed external commitments.

The gap is less alarming than it first appears, because these facilities are not fixed project-finance tranches drawn on a schedule. HCB has been explicit that the combined credit and grant may be called on flexibly.

The combined €225 million in AFD and AfDB credit plus the €22 million EU grant “may be disbursed if the company needs and judges necessary” over the life of the programme, according to HCB.

That single clarification is the most analytically significant statement in the whole financing structure. It tells you the development finance functions as available programme finance, not committed capital. The remaining balance is expected to come from HCB’s own revenue generation across the decade.

The choice of instrument matters. AFD’s loan is concessional and non-sovereign, meaning it carries below-market terms and is extended to the company rather than backstopped by the Mozambican state. In a sovereign with constrained fiscal space and a long-tenor infrastructure asset, purely commercial debt would demand a far steeper risk premium, if it were available at all.

Blended sovereign co-investment structures have shifted significantly in scale across the past two years, with development finance institutions moving toward larger concessional envelopes precisely because constrained-sovereign borrowers cannot access commercial debt on viable terms for long-tenor infrastructure assets.

Read the structure as a deliberate design choice rather than a shortfall. Development finance institutions are the logical lenders here precisely because the risk profile, long horizon, and public-good character of the asset deter commercial capital. The flexibility carries its own catch, though: if facilities are drawn at HCB’s discretion, actual capital deployment could lag the technical timeline whenever revenues tighten.

What the dam actually does for Southern Africa’s grid, and why that matters now

Two-thirds of everything Cahora Bassa produces leaves Mozambique for South Africa. That is the number to hold onto. In 2024, Eskom took 8,319 GWh, or 66% of HCB’s total deliveries, dwarfing domestic and other regional offtake.

Put those figures together and an abstract infrastructure story becomes a live regional supply risk. This is a regional facility that happens to sit in Mozambique, not a Mozambican plant that occasionally exports.

Production held up in the near term. First-half 2024 output reached 8,396 GWh, up 4.77% year on year, with the reservoir at 59.2% of useful storage at that point. But the water is the variable that governs everything.

At HCB’s 50th-anniversary conference in May 2025, executive board member Nilton Trindade set out the constraint plainly.

The drought affecting the reservoir since 2023 is the worst in four decades and is restricting hydroelectric production, with direct impacts on company revenues and on energy security “not only internally but also neighbouring countries that depend on our supply,” Trindade said.

That is the crux of the timing. CAPEX Vital addresses ageing equipment and climate exposure at the same moment, because a drought-constrained plant running on deferred maintenance is a compounded risk, not a single one.

Cahora Bassa also plays a role that variable renewables cannot fill. It supplies firm, dispatchable baseload into a Southern African Power Pool (SAPP) system otherwise heavily weighted toward coal. That makes the overhaul a low-carbon infrastructure story alongside its maintenance logic, and it explains why a planned North Power Station could one day add roughly 1,245 MW to the complex.

Here is what the Eskom concentration means for you as an investor. A prolonged disruption at Cahora Bassa, whether from drought or slipped rehabilitation, becomes a supply security problem for South Africa’s grid, not merely a Mozambican one. It also concentrates HCB’s revenue: the financial health of a ten-year programme depends materially on the South African power market’s continued ability to absorb and pay for this output.

Eskom’s supply position heading into winter 2026 matters directly to Cahora Bassa’s revenue model: a South African grid that is tighter on capacity has less flexibility to absorb shortfalls from a drought-constrained or partially offline Cahora Bassa without activating load-shedding.

How the Kariba precedent reframes the risk calculation for CAPEX Vital

There is a close regional mirror for this kind of work. The Kariba Dam Rehabilitation Project, backed by AfDB, shows what happens when a comparable Zambezi-basin asset addresses structural risk before it becomes catastrophic.

The Inga II modernisation offers the closest available African comparator: a large-basin hydroelectric asset restored to capacity through a structured rehabilitation programme, with the same blended financing logic and similar sequencing constraints that define CAPEX Vital.

According to AfDB’s Implementation Progress and Results report of October 2024, plunge-pool works at Kariba have reduced the risk of dam-foundation failure and are expected to extend the structure’s life by around 50 years. Once spillway rehabilitation completes, the project will secure the safety of more than 3 million people living downstream.

Invert that outcome and you see the cost of inaction. The Kariba case is the clearest available evidence that structured, development-finance-backed rehabilitation delivers measurable life-extension and safety results, even across long timelines. For an investor, CAPEX Vital reads as a defined capital programme with precedent-backed logic, not a speculative new-build.

The three risk categories investors should track

The Kariba experience and the wider Southern African hydro literature point to three distinct risks worth watching across CAPEX Vital’s life.

• Hydrological risk: drought variability and its direct hit to generation and revenue
• Implementation sequencing risk: the cascade effect built into a one-unit-per-year schedule
• Governance and management-capacity risk: the source that infrastructure diagnostics identify as the main cause of rehabilitation delay

On the first, the observable indicator is straightforward: track reservoir storage levels against the 59.2% useful-storage benchmark seen in mid-2024, and watch each year’s delivered GWh against the 12,351 GWh full-year 2024 figure. A sustained decline signals revenue pressure that could slow discretionary drawdowns of finance.

On the second, the schedule is both the programme’s strength and its sharpest exposure. The first of five units is due to begin rehabilitation in 2028, at one unit per year, implying the unit sequence completes around 2032 while the overall programme runs to 1 December 2037. Doing one unit at a time avoids a full plant shutdown, but a single year’s slippage at the 2028 start cascades through every unit after it. Watch the 2028 commencement date as the anchor for the entire timeline.

On the third, AfDB classifies the environmental and social risks tied to HCB’s corporate loan facility as High Risk, which means robust safeguard requirements and the potential for timeline friction from the outset. The indicator here is the pace at which environmental and social conditions are cleared before physical works begin.

Hold that scheduling dependency in mind whenever the 2037 completion date is quoted. It rests on a first unit that has not yet started.

What a rehabilitated Cahora Bassa means for the Southern African Power Pool’s energy transition

Shift now from risk to the forward question. If CAPEX Vital delivers, what does a modernised 2,075 MW baseload asset do for SAPP’s ability to decarbonise and manage demand?

The headline outcome is longevity. According to the AFD project fiche, the rehabilitation aims to extend the operational life of Cahora Bassa’s generating equipment by at least 25 years. That secures the region’s primary low-carbon baseload anchor through at least the 2050s.

AFD’s CAPEX Vital project documentation confirms the 25-year minimum life-extension target alongside the concessional, non-sovereign loan terms, providing the primary public record of what the French development lender expects the rehabilitation programme to deliver against its capital commitment.

The programme reaches beyond the turbines. Modernisation of the Songo converter substation, part of the same envelope as the unit overhauls, targets transmission capacity and grid reliability, not just generation. Both are needed for SAPP to move power across borders efficiently.

The EU grant component signals that the overhaul is designed to modernise the plant’s operating intelligence, not only its steel and concrete. That roughly €22.1 million envelope covers a spread of domains.

• Digitalisation of plant systems
• Cybersecurity of critical infrastructure
• Reinforcement of transmission lines
• Reservoir water management and vocational training

There is a sustainability framing attached to all of this.

AFD funding aims to extend equipment life by at least 25 years and help HCB maintain its position as a key supplier of green energy in the region, according to the project documentation.

For an analyst tracking the regional transition, a completed CAPEX Vital changes the calculus. Cahora Bassa enters the 2030s as a modernised, digitally capable, climate-resilient baseload asset rather than an ageing plant operating on borrowed time. That reframes every coal-to-renewables planning document in the SAPP footprint, since a firm low-carbon anchor lowers the reserve-margin burden that new renewables would otherwise have to carry.

The wider value is a template. Blending development finance, EU grant instruments, and utility internal capital to sustain large hydro in a constrained-sovereign context is a model with direct relevance to comparable rehabilitation opportunities across sub-Saharan Africa. (One frequently cited figure, that HCB accounts for roughly 78.7% of Mozambique’s electricity production and exports, appears in secondary commentary but has not been independently verified and is best treated as contextual only.)

Whether CAPEX Vital succeeds depends on three conditions outside the engineering

The engineering case is well established and the financing architecture is in place. The programme’s ultimate success, though, turns on conditions no amount of capital can fully control.

1. Hydrological normalisation, or credible climate-resilient operating adjustments. The 2023 drought, the worst in 40 years per HCB’s board, is a direct threat to the revenue that must fund the bulk of the €1.2 billion outlay.
2. Stable SAPP offtake arrangements. Eskom’s continued capacity to absorb and pay for the 8,319 GWh it took in 2024, some 66% of deliveries, underpins the whole revenue model.
3. Governance and implementation discipline. A decade-long sequential schedule, with the first unit due in 2028 and completion targeted for December 2037, leaves little room for slippage.

Cross-border power trading dynamics in the SAPP footprint are evolving rapidly, with new bilateral energy links being established that will eventually compete with or complement Cahora Bassa’s long-standing role as the region’s primary hydro export hub.

The blended-finance structure, the flexible disbursement approach, and the involvement of AFD and AfDB all provide genuine risk mitigation. None of them resolves the fundamental exposure to Southern Africa’s water cycle. That exposure is the one variable the confirmed €247 million development finance envelope cannot hedge.

The Kariba precedent is the reason for measured optimism: a comparable programme, well executed, delivered a roughly 50-year life extension and safety for more than 3 million people. CAPEX Vital represents the most significant single capital programme in the region’s hydroelectric base over the next decade. Track its three domains separately, each with its own observable indicators, and you are better positioned than anyone treating this as a binary completed-or-not event.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions. Past performance does not guarantee future results. Financial projections are subject to market conditions and various risk factors, and forward-looking statements are speculative and subject to change based on market developments.