Leaders in renewable energy independent power production say the National Energy Regulator of SA (Nersa) is stalling approval of a curtailment framework. This framework is crucial for facilitating greater grid access in the short term and allowing new projects to connect to the grid.
At a renewable energy seminar hosted by the electricity & energy ministry on Monday, Segomoco Scheppers, the interim CEO of the National Transmission Company (NTCSA) said the request to Nersa this year to classify congestion curtailment as a constrained generation ancillary service was still “under consideration”.
The renewable energy sector wants the regulator to act faster. SA Independent Power Producer Association chair Brian Day said curtailment was the only viable short-term solution to securing more grid access in areas where capacity had run out. But Nersa was “a huge bottleneck”, he said. Day questioned whether Nersa was “fit for purpose for the radically changing [energy] environment in SA”.
In an addendum to its 2025 Generation Connection Capacity Assessment (GCCA), Eskom outlined how a 10% curtailment measure would allow for 3,470MW of new wind power projects to be connected to the grid.
The GCCA, published last year, revealed that sections of the transmission network in prime wind-generation regions such as the Eastern Cape and Western Cape were at full capacity, having been exhausted by earlier bid rounds and private off-takers. Due to these grid limitations, no new wind power projects were approved for development in bid window 6 of the Renewable Energy Independent Power Producer Procurement Programme (REIPPPP).
But the curtailment framework published earlier this year stated that if project developers accepted a “reasonable share” of no more than 10% curtailment, 3,470MW additional wind generation capacity could be connected to the grid in these provinces. Curtailment refers to limiting output from a renewable energy plant to levels below its potential to respond to transmission capacity constraints. This offers developers with an alternative if they decide to connect in constrained grid areas.
Risk
Several wind energy bids were received under the latest 7 REIPPPP round, most of them to be located in the Cape provinces. Bid window 7 seeks to procure 5,000MW of new generation capacity, of which 3,200MW is expected to come from onshore wind power. But until Nersa approves the curtailment framework it is uncertain whether these projects could proceed, creating the risk that bid window 7 would be another failed procurement round for the wind power industry.
Seminar speakers, including Day and Tshifhiwa Bernard Magoro, head of the IPP office, identified the shortage of grid access as one of the main challenges for the renewable energy sector, posing a hurdle to investment. SA needs an estimated R390bn to strengthen its transmission capacity and connect new energy projects to the grid. This is required to fund Eskom’s transmission development plan, which outlines the need for the installation of more than 14,000km of new high-voltage power lines by 2032.
Day said Eskom built only 74km of new transmission lines in the previous fiscal year, well below the 166km target. It should build 1,400km a year. It will take years, he said, before substantial new grid capacity is built. To ensure renewable energy capacity would be added to the grid in the meantime, the only solution was to implement the curtailment regime Eskom proposed. It had been sitting with Nersa.
Electricity & energy minister Kgosientsho Ramokgopa admitted previously to capacity challenges at Nersa, saying he did not think Nersa was “geared” to respond to the SA energy sector’s evolving nature. The chair and CEO requested government assistance to address the challenges.
Mercia Grimbeek, head of project development at renewable energy company Enertrag, said at the seminar that project developers were “happy to accept some curtailment” but also wanted the government to consider other changes to the REIPPPP model. Having smaller, more frequent procurement rounds (rather than the “mega rounds” now being launched) would ensure more consistency in renewable energy procurement because the “mega-rounds” came with unintended bottlenecks, she said.
The programme could also provide for co-location of projects, allowing a single grid connection to be shared between a solar project and a wind project, for example.
Magoro highlighted the need to add more wind power to the grid to ensure greater grid stability, saying that SA was already seeing a “duck curve”, an imbalance between energy demand and supply on days when solar energy production is high and demand on the grid is low.
Some speakers were critical of Nersa’s rejection this year of Eskom’s request to reserve grid capacity for renewable energy projects procured by the state under the REIPPPP.
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