Eskom CEO Andre de Ruyter reports that overt and covert security is being beefed up in and around the utility’s power stations following suspicious incidents at Matimba and Lethabo on November 17 that are suspected to have not been “entirely coincidental”.

In a briefing on the state of the system, which descended into load-shedding again on Wednesday, De Ruyter emphasised that he was typically wary of attributing to “malice what could be explained by incompetence”.

Nevertheless, he confirmed that the tripping of three units at the Matimba power station had become the subject of a forensic investigation.

The breakdown occurred when a team working on the dry-cooling fans at the power station allowed an extension cord to drop on to the transformer at Unit 2. This resulted in a flash that tripped the station board, shutting off cooling to Units 1, 2 and 3, and causing the three units to shut down.

“We have difficulty believing that this is entirely coincidental,” De Ruyter said.

A forensic team had been sent to the site to investigate and additional security would be deployed to Matimba.

“We have no hard evidence of sabotage at this point in time,” he stressed, but added that the incident had “certainly aroused suspicion”.

Likewise, Eskom was investigating an incident at the Lethabo power station, where one of the distribution-line towers collapsed in such a way as to damage a second line, which was in place to provide power redundancy to the coal conveyor system at the station.

The incident, which made both lines inoperable, occurred at about 18:00 on November 17, ahead of evening peak, and Eskom was investigating the incident, which would have led to a shutdown of the station within six hours, had an innovative engineering solution not been found.

It was also closing in, with the help of the police, on a “network” of coal transporters that had been tampering with seals used to hold tarpaulins in place over the coal during transport.

Eskom believes the network is skimming coal and replacing it with material that is damaging power stations mills and boiler tubes.

The tarpaulins and seals were introduced to safeguard the integrity of coal in transport from the mines to the power stations so as to prevent any coal theft and the introduction of incombustible material or rocks, which are known causes of boiler-tube leaks.

One transporter was recently found to have 60 broken seals in the cab of a truck, suggesting ongoing theft of coal.

Despite these incidents, the level of unplanned losses had been reduced from over 15 000 MW on Wednesday to below 14 000 MW.

This reduction together with relatively low levels of planned maintenance of 3 910 MW means that Eskom is expecting to lift Stage 2 load-shedding at 21:00 on November 18, and reintroduce rotational cuts at Stage 1, from 5:00 until 21:00 on Friday.

It does not expect to reinstate load-shedding over the weekend.

De Ruyter said that planned maintenance was continuing in line with its programme, but acknowledged that it was lower than initially hoped, owing to ongoing liquidity constraints.

These constraints meant that it could not secure the spares it required ahead of time to carry out maintenance at higher levels.