Eskom managers overruled engineers at Kusile power station, ordering them to run a unit at full capacity, which led to a catastrophic incident that is still costing the country more than two stages of load-shedding.
An internal Eskom report that the Sunday Times has seen sheds light for the first time on how unnamed bosses at Megawatt Park gave verbal instructions to return unit 1 at Kusile to service and run it at maximum capacity, even though a critical component had failed and needed to be repaired.
This decision, which made available an extra 800MW of power to the grid at the time, led to a section of the plant collapsing and caused the loss of three units at the power station producing 2,400MW of power, which still hasn’t been restored.
Only one unit at Kusile, one of the country’s two newest power stations, is now operational. Units five and six have not yet been completed. Kusile was supposed to produce 4,800MW of power by 2013, but it is a decade over time and billions of rand over budget.
The incident last October, in which a poorly designed and built chimney at Unit 1 collapsed, affected units two and three of the Mpumalanga power station which share the same chimney.
Work to bypass the damage and return the units to operation is expected to be completed only by the end of the year.
The report, compiled after an internal investigation led by an official from Eskom’s assurance and forensic department, found the unit had been problematic since 2021. It had been partially repaired but the repairs had been poorly done.
The report said there were four forced outages of the unit between March and October last year for the same reasons, and Kusile’s engineers had warned about the risk of failure as well as poor workmanship by those conducting the repairs.
“A decision was made to continue running the plant, knowing that the chimney was building up sludge,” the report found.
However, the report is silent on who issued the instruction.
“The root cause of the incident was management’s decision to continue running the plant above 500MW, knowing that the chimney was building up with slurry due to known deficiencies,” the report stated.
Senior Eskom insiders said the instruction came from company headquarters.
Kusile was supposed to produce 4,800MW of power by 2013, but it is a decade over time and billions of rand over budget
The instruction had been issued verbally and informally, and investigators could find no evidence of who in Eskom management gave the order to run the plant against the engineers' advice.
“During the investigation, no auditable trail or evidence was provided on the decisions made to continue running the plant with a compromised FGD,” the report stated.
The FGD is a flue gas desulpherisation plant, a component of the chimney system that broke, leading to the collapse.
The month before the incident, the county had been experiencing severe load-shedding, hovering between stages three and five.
The report continued: “From all the facts acquired about the plant design and operation, it is clear that the power station technical staff responsible for the plant predicted the failure.
“Continuous decisions taken to favour production above plant health led directly to ... failure.”
This week Eskom declined to comment.
“The investigation into the collapse of the chimney system of Unit 1 of the Kusile Power Station is still ongoing. Eskom is therefore not in a position [to comment] further until the completion of the investigation,” said spokesperson Sikonathi Mantshantsha.
“In the meantime, as previously communicated, Eskom is working on providing a temporary solution to the chimney system and anticipates all the units to be back in service by the end of the year.”
At the time of the collapse, Eskom opened an official investigation into the incident which was also discussed in parliament, where former Eskom CEO Andre de Ruyter said that by introducing the FGD plant, Eskom had introduced “a single point of failure” through a technology that was not well-known to them, which the entity did not have the requisite skill to operate. He did not provide further details about the breakdown.
Eskom is building a temporary chimney system for all three units which will bypass the damaged unit, Mantshantsha said, adding that Kusile’s unit 1 is expected to be back online by late November, followed by units 2 and 3 in December.
Eskom is applying for an exemption from the department of environmental affairs to operate the units without the FGD plant while a permanent solution is sought. The FGD plant, designed to reduce harmful emissions, was the only one of its kind in Africa.
Energy expert Lungile Mashele said: “Even though this current management accused their predecessors of running the plants hard, with an energy utilisation factor that was higher than international norms, it was never to a point that the plant had to break down.
“Maybe one can even attribute this to the utterances of the [department of public enterprises] which has said before that Eskom needs to run their plant so that we avoid load-shedding. Also the CEO, COO, the GM for generation and the power station manager allowed this,” she said.
“Is this not why we’ve been seeing a mass exodus of generation employees, including two general managers? Are they being told that you either run the plant a certain way or you leave? At the same time, they are under pressure because the plant is not performing, and they know what they’re doing is breaching how the plant is meant to be run.”
A senior Eskom insider, who spoke on condition of anonymity, said it was common for some Eskom leaders to issue verbal instructions, rather than written directives, when it came to taking risks.
“It's part of the morale issue, because there have been lots of suspensions and dismissals for what people perceive to be mistakes. So, in the same vein as no-one taking risks for fear of losing their jobs, people also give verbal instructions so it's easy to deny when things go wrong,” he said.
On October 23, Eskom announced that a section of Kusile unit 1’s flue gas duct collapsed at the point at which it connected to the chimney that services the first three of Kusile’s six units.
The flue gas duct, a pipe with a diameter of about nine meters, is part of the unit that prevents sulphur dioxide from being sent into the atmosphere.
“While it is uncertain at this point, it is anticipated the unit may remain offline for a few months. The duration will become clearer over the next few weeks. Access to the area has been restricted as part of precautionary measures,” the utility said at the time.
“Consultations with various specialist stakeholders, including the original equipment manufacturer, are in progress to determine best course of action to restore the plant as quickly as possible.”
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