Compiled by the Council for Scientific and Industrial Research (CSIR) Energy Centre, the statistics highlight a particularly strong correlation between the daily generation profile of the country’s 1 479 MW solar photovoltaic (PV) fleet and the times of the day that load-shedding occurred in June, July, November and December.
In total, Eskom resorted to rotational power cuts on 12 days last year, equating to 128 hours of either Stage 1 (1 000 MW), Stage 2 (2 000 MW), or Stage 3 (3 000 MW), or about 138 GWh of unserved energy.
The utility began resorting to load-shedding again in 2019, declaring Stage 4 (4 000 MW) from 13:00 on February 11. Eskom last declared such a large level of load-shedding during its 2014/15 financial year under its previous Stage 3 definition, which had a wider range and which has since been revised to one where each stage represents 1 000 MW.
Last year, most of the incidents took place in late November and early December. Supply has been negatively affected by the fact that Eskom’s summer maintenance coincided with high levels of unplanned breakdowns across the coal fleet, exacerbated by inadequate coal supplies, poor coal quality and sub-par contributions from the units in commercial operation at the Medupi and Kusile power station projects.
Although still a small contributor to South Africa’s overall production of electrical energy, the CSIR statistics show that the country’s operational utility-scale wind, solar PV and concentrated solar power (CSP) plants helped mitigate the impact of the system’s imbalances.