Potential Risks Associated with Eskom’s Strategic Maintenance Strategy

On Sunday morning, Minister of Electricity and Energy Kgosientsho Ramokgopa struggled to clarify what he describes as Eskom’s “calculated aggression” regarding planned maintenance, which has led to a decrease in the reserve margin of Eskom’s electricity network.

The utility unexpectedly lost 10 generating units, necessitating the implementation of Stage 6 load shedding shortly after midnight on Saturday, 22 February. Eskom aims to decrease the severity of load shedding throughout the week and hopes to suspend it by the week’s end.

Read: Stage 6 load shedding impacts South Africa

During a media briefing on Sunday morning, Ramokgopa, along with Eskom leadership, sincerely apologized for the “agitation, frustration, and anger” caused to South Africans by the severe load shedding, which has left electricity users powerless for eight to ten hours daily.

Eskom reduced load shedding from Stage 6 to Stage 4 just before 1 am on Monday morning, ahead of the work week. It announced that Stage 4 would remain in effect “until further notice.”

“This decision comes after the successful recovery of all five units at Majuba, two units at Camden, and one unit at Medupi since Saturday, summing up to eight out of ten generation units that had tripped this weekend.

“Moreover, the replenishment of emergency reserves is proceeding well,” noted the state power utility.

This marks the second setback in Eskom’s efforts to eradicate load shedding, following the implementation of rolling blackouts on January 31, which ended a 300-day period of continuous power supply.

Even darker times for some

For certain residents in Pretoria, who experienced significant power outages last week due to issues with the municipal distribution network, the weekend’s load shedding was hardly a change, as they had already been without electricity for four consecutive days by Sunday morning.

In reaction, Freedom Front Plus Councillor Peter Meijer reached out to Tshwane Executive Mayor Nasiphi Moya:

Good morning EM,

The conditions in the affected areas (Bergtuin, Waverley, Môregloed, Queenswood, Kilner Park, Villieria) among others are now intolerable and unacceptable.

In light of the ongoing load shedding, electricity supply remains erratic, with power flickering on and off, and in some locations, it hasn’t returned at all.

Given the circumstances, we request that the affected areas be exempt from load shedding for at least the next 48 hours. This exemption has been granted to other suburbs in the past. We kindly ask for a prompt response.

Regards, Cllr Peter Meijer

Meijer confirmed on Sunday afternoon that he had not received a response from the mayor.

Eskom caught off guard

The load shedding over the weekend clearly took Eskom by surprise.

On Friday afternoon, the utility issued its routine Power Alert, stating: “Eskom confirms that load shedding remains suspended, backed by a stable power system and sufficient emergency reserves.”

However, this swiftly changed when Eskom issued a WhatsApp notification on Saturday afternoon, indicating: “Following more than 20 days of uninterrupted electricity supply, Eskom has faced another temporary setback. Consequently, Stage 3 load shedding will be enacted from today at 17:30 until further notice…” (This message was sent at 17:32.)

Shortly after at 01:52 on Sunday morning, load shedding escalated to Stage 6.

The explanation …

During the hastily organized media briefing on Sunday morning, Ramokgopa explained that Eskom had significantly increased its planned maintenance, taking 7,500MW of generation capacity offline for required repairs.

However, Eskom’s most recent weekly system status bulletin (for the week ending 16 February) indicates that planned maintenance levels were even higher a year prior.

Ramokgopa stated that Eskom needs to undertake more planned maintenance to mitigate risks to certain units.

It must approach its maintenance with “calculated aggression,” he emphasized.

As a result, there will occasionally be unforeseen instances, like on 1 February when several units tripped, including two of Eskom’s most dependable power stations, Matimba and Lethabo. This forced Eskom to resort to load shedding to allow for the replenishment of its emergency reserves.

The same scenario occurred this past weekend when several units at Majuba and one unit at Medupi tripped unexpectedly, leaving Eskom with 3,864MW of generation capacity unavailable. Stage 3 load shedding was implemented to enable Eskom to replenish its emergency reserves and stabilize the power system.

Overnight, four units at Camden also became unavailable, prompting the escalation of load shedding to Stage 6.

Additionally, one of the units at Koeberg, which has a generation capacity of 900MW, is offline due to planned maintenance, and there are ongoing works to connect three units at Kusile to rebuild the permanent stack, impacting available generation capacity.

Majuba-to-Medupi chain reaction

Eskom CEO Dan Marokane explained that the trips at Majuba followed the restart of a unit that had previously been out of service. One of the transformers experienced an overload, initiating a chain reaction.

This incident caused a drop in the system frequency, triggering a trip on one of the units at Medupi.

Meanwhile, issues at Camden arose after a hydraulic valve failure affected the cooling water pumps.

Where to now

Six of the ten units lost overnight have already been returned to service, and Eskom will reevaluate the situation after the evening peak on Sunday night, Marokane stated.

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Eskom chairman Mteto Nyati indicated that, in its planned maintenance, Eskom has concentrated on the core generation plants at its coal-fired stations.

However, recent issues have occurred within the balance of plant, necessitating a shift in focus to avert similar failures in the future.

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