South Africa's electricity minister has turned a daytime surplus into a procurement order. On 7 October, Dr Kgosientsho Ramokgopa confirmed the first section 34 determination under the Integrated Resource Plan 2025: 4,600 MW of battery energy storage and 5,000 MW of gas-to-power, with no new wind or solar in this round. The combined 9,600 MW is meant to soak up power the grid cannot use at midday and deliver it when the evening peak arrives.
The shift would have sounded implausible three years ago, when load-shedding defined the politics of power. Eskom's generation recovery and a wave of private solar have left the system with average daytime surpluses above 4,000 MW, the minister said. That surplus is now a cost. Generators are curtailed, contractual payments continue, and usable electricity is thrown away.
What the determination prioritises
The government statement of 7 October says the first determination answers immediate needs for storage, flexibility and dispatchable supply. A later determination will cover wind, solar, hybrids with storage and longer-term pumped storage. Batteries are meant to charge from electricity that would otherwise be curtailed and discharge in the evening peak or other tight periods, at sites chosen so they do not recreate the same network constraint.
Procurement will be run by the Independent Power Producer Office and opened to all market participants, including Eskom, Engineering News reported. Eskom is already prequalifying partners for a 6 GW green pipeline that includes 1,000 MW / 4,000 MWh of batteries. No storage duration was fixed in the new 4,600 MW allocation, and no capacity factor was given for the gas plants.
Ramokgopa told a Pretoria briefing that the ministry is taking the full IRP 2025 battery allocation now rather than phasing it to 2030, because the curtailment problem is already here. TechCentral quoted him saying the country is sitting with surplus electricity that represents a major risk, losing power and throwing money away. ESI Africa reported his line that the problem is now and that waiting risks a blackout from overcapacity of the wrong kind: too much midday energy and not enough evening flexibility.
The money and the precedent
South Africa already has a battery programme to build on. By June 2025, all five projects in the first battery storage bid window, 513 MW in total, had reached commercial close and entered construction with R15.4 billion of investment, according to the government statement. Engineering News put total battery capacity procured to date at 1,744 MW / 6,976 MWh. Ramokgopa put likely investment in the new 4,600 MW allocation at upwards of R90 billion, TechCentral reported.
That scale changes the manufacturing and grid-connection agenda. Storage will need locations that can charge from surplus zones and discharge into load centres without recreating congestion. The System Operator's charging and discharge requirements are supposed to sit inside the tender rules, with enforceable availability and performance obligations. Local manufacturing, engineering and ownership commitments are flagged as measurable conditions rather than optional extras.
Why gas sits beside batteries
The 5,000 MW gas-to-power slice is not designed to absorb surplus. It is designed to run when renewables fall away or demand rises. The government statement says procurement design must address start-up times, ramping, minimum operating levels, fuel availability, delivered gas prices, port and pipeline infrastructure, grid connections and commissioning schedules. Affordability is to be tested against the expected operating profile, not against baseload assumptions that the plants are unlikely to meet.
That pairing is the IRP's short-term answer to a duck-curve problem. Batteries move midday energy into the evening. Gas covers longer gaps and multi-day wind lulls that batteries sized for daily cycling will not. Transmission expansion, new industrial demand and regional trade are listed as the accompanying work, because storage alone cannot fix a constraint on the wires.
Surplus without affordable access
The politics cut both ways. Ending load-shedding was the mandate. Keeping tariffs high while the system curtails power invites a different backlash. Ramokgopa acknowledged the tension: Nersa, not Eskom, sets tariffs, and the electricity pricing policy is being revised for the first time since 2008. ESI Africa reported that the ministry is modelling how daytime surplus could deliver relief to households and industry, subject to Nersa approval, and that for many households the issue is not supply on the grid but the ability to buy units.
Crypto mining has been floated as another flexible load. Ramokgopa confirmed that the ministry, Eskom and Nersa have engaged players who say they could use 1 to 3 GW within two years on existing infrastructure at sites earmarked for repurposing. He expects Eskom to make a formal announcement. Mining load would soak surplus without building batteries, but it would not move energy into the evening peak the way storage does.
Regional trade offers a fourth outlet. If daytime surplus can move into neighbouring grids that still face deficits, curtailment falls without waiting for every battery to reach commercial operation. That path depends on interconnectors, wheeling rules and counterparties willing to take shapeable blocks. It will not replace the 4,600 MW storage build, but it can reduce the volume batteries must shift in the first years of the programme.
Industrial users are watching for a different signal: whether surplus can become interruptible or time-of-use products at prices that revive smelters, data centres and manufacturing loads mothballed during the load-shedding years. If Nersa's pricing review creates those products, the determination's gas tranche may run fewer hours than critics fear. If it does not, Pretoria will have built flexibility for a demand base that still cannot afford to switch on.
What to watch
Three tests will show whether the determination becomes steel. The first is how fast the IPP Office opens the battery round and whether duration and location rules match the System Operator's curtailment map. The second is gas fuel supply: without firm LNG or pipeline gas, 5,000 MW of turbines are optionality on paper. The third is the tariff track at Nersa. A system that curtails at noon and still raises household rates will struggle to claim the surplus as a public win.
For now, Pretoria has named the problem correctly. South Africa's shortage has flipped to a timing problem. The procurement that follows will decide whether the extra midday megawatts become evening supply or remain wasted generation on a grid that finally has too much power at the wrong hour.