Curtailment will allow more wind projects
In an addendum to its 2025 Generation Connection Capacity Assessment (GCCA), Eskom has outlined how introducing 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 indicated that parts of the transmission network in the most favourable areas for wind generation such as the Eastern Cape and Western Cape had no capacity, as all of the capacity has been depleted from previous bid window rounds and private off-takers, according to Eskom.
These grid constraints resulted in no new wind power projects being selected for development under bid window 6 of the renewable energy independent power producer procurement programme (REIPPPP).
However, the curtailment framework set out in the addendum last week states that if project developers accepted a “reasonable share” of no more than 10% curtailment, 3,470MW (equal to more than three stages of load-shedding) of additional wind generation capacity can be connected to the grid in these provinces. Curtailment, the reduction of output from a renewable energy plant below what it could produce to respond to transmission capacity constraints, will provide developers with an alternative if they still choose to connect in constrained grid areas.
This opens the doors for wind-energy projects to be located in the Cape provinces to submit bids under window 7 of the REIPPPP. Bid window 7, which was launched in December, seeks to procure 3,200MW of wind power.
Eskom was able to publish the addendum now after the implementation of curtailment passed through the necessary governance process in 2023.
“Governance within Eskom has been approved to a large extent, and regulatory support was confirmed by Nersa [the energy regulator] in December 2023,” Eskom said.
The utility warned that power procurement in local municipalities would negatively affect the “new” generation connection capacity that could be realised through curtailment if the procurement is successful, located in the Western Cape and Eastern Cape, and if it is dispatched during times of congestion.
The Western Cape, for example, has a target to add 5,700MW of renewable power from independent power producers.
The renewables industry has largely been receptive to the implementation of curtailment to open up more grid space in areas with limited capacity.
Leaders in the sector have previously told Business Day that mandatory curtailment would not be detrimental to investment in renewable energy in SA. However, there needs to be certainty and predictability about the amount of curtailment that will be required and how it would be executed.