Eskom’s unexpected load shedding sparks concerns over energy reliability

Energy experts have raised concern about the reliability of Eskom's energy supply after the power utility unexpectedly implemented load shedding on Wednesday night following the loss of five generation units.

This announcement marked Eskom's fourth load shedding declaration this year, leading to significant disruption during peak energy demand hours.

Prof Vally Padayachee, energy expert and former Eskom generation executive manager, said that Eskom had, prior to the last four load shedding declarations, made reasonable progress in their generation recovery efforts.

“However, it faced on Wednesday the loss of five generation units before the evening period. The loss of five generating units before and during this Wednesday evening peak period necessitated the implementation of Stage 2 load shedding for 10-and-a-half hours overnight,” he said.

Padayachee added that this seemed to be a new cause or challenge that has “reared its head” as two of these units were “cross border related” emanating from the Cahora Bassa hydro-dam in Mozambique.

“Overnight on Thursday, four of the five units were rapidly restored and brought back online, along with two additional units from previous outages, resulting in a total generation recovery of approximately 3 000MW.”

Padayachee said that although Eskom has repeatedly indicated that it continued to prioritise planned maintenance to strengthen system reliability ahead of the winter months while ensuring adherence to environmental and licensing conditions, the generation system, by Eskom’s own admission, still has inherent risks.

“It is, therefore, my opinion that unless Eskom reaches an overall generation system Energy Availability Factor of 70% to 75% and a reserve margin (headroom) of total supply in excess of demand of 10% to 15%, then we unfortunately will still continue to experience these bouts of sporadic stages of load shedding,” he said.

“The forthcoming winter period is vulnerable because it is colder and the demand for electricity is much higher.”

Ruse Moleshe, managing director of RUBK, an energy and infrastructure consulting and advisory firm, said that in the recent past, Eskom has given various reasons for the load shedding that has taken place, including auxiliary equipment like transformers connected to a number of generators tripping.

“This could be due to many reasons, including staff issues. We do not know with certainty what those are,” Moleshe said.

“The problem is made worse by the significant capacity that is out for maintenance, typically done in summer to prepare for reliability of plants for the winter period.”

Moleshe said that this capacity should be back on stream by the end of March to serve the winter demand.

“At an Eskom level, there were some issues. These would not be so prominent if we had sufficient reserve capacity (backup or caution against the risk of load shedding) to come on stream during such emergencies.”

Moleshe said that the President's Energy Action Plan to help address supply constraints in the country wanted to tap into private and regional capacity to augment Eskom efforts, but this has not been realised due to a number of reasons, including local and regional transmission bottlenecks.

“Some countries in the region have supply challenges of their own. Without significant transmission infrastructure and additional reliable capacity such as gas, the country should know that load shedding can be addressed, but the system remains vulnerable to the risk of non-performance.”

Moleshe added that the UK recently also faced supply challenges, but due to regional integration and modernised interconnectedness, they were able to rely on European Union supply to back up their systems.

“South Africa does not benefit from similar intervention. So we need to invest in more capacity. Eskom is a significant part of the solution, but not the only solution that can fully address our challenges,” she said.

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