As the South African government seeks to re-establish some momentum behind the public procurement of new independent power producer (IPP) generation and storage, much focus will be on how bidders adjust to the grid constraints, as well as Eskom’s new curtailment regime when they submit responses to the bid windows launched in December.

Eskom’s processes for providing grid-connection cost estimate letters and budget quotes have long been a bone of contention. Increasingly, though, the physical constraints associated with years of underinvestment in both transmission and distribution networks have emerged as the major obstacle; one that cannot be fully cleared without investment, but which will certainly be eased by Eskom’s new approach to curtailment.

There is no question that Eskom is still finding its feet operationally as the system begins its slow transition away from its current reliance on mega-scale generators that are geographically concentrated to one that increasingly includes smaller, decentralised and variable generation technologies. While many other system operators globally have become accustomed to this new electricity supply reality, the South African system operator is not yet fully comfortable that it is able to sustain system balance as more and more variable renewables plants enter the network.

This, despite relatively low penetration rates of about 14%. Until recently, Eskom has displayed this discomfort by opting for a conservative stance when it comes to integrating new generators, which some argue has led to the grid constraint being made even more acute than it ought to have ever been. This philosophical stance became particularly evident during the sixth bid window of the renewables programme, when none of the wind projects advanced to preferred-bidder status after Eskom indicated that the grid capacity on which those projects were bid had been absorbed.

The outcome triggered debate regarding Eskom’s approach to the grid. Questions, for instance, were asked about why a mechanism such as curtailment had not been employed to optimise the use of the grid and to facilitate the injection of much-needed energy that could have arisen from the 3 200 MW wind allocation. Now, Eskom has taken a big step forward in this regard by publishing the long-awaited curtailment addendum to its latest Generation Connection Capacity Assessment, which stated there to be 19.9 GW of remaining grid capacity nationally but with zero capacity in the Eastern, Northern and Western Cape provinces.

By accepting a reasonable share of no more than 10% of curtailment, the addendum indicates there to be 3 470 MW of additional grid capacity to connect wind generation, including 2 680 MW in the Western Cape and 790 MW in the Eastern Cape. This could be a game changer for the prevailing renewables bid programme, which was previously mostly restricted to areas outside of these two provinces, unless projects had existing budget quotes, or could secure expired capacity. At the time of writing, it was not clear whether the new curtailment framework would be integrated into the round. If it is, it will be fascinating to see how bidders and their bankers respond.