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Load shedding is back, with Eskom scrambling to protect emergency reserves

Load shedding is back, with Eskom scrambling to protect emergency reserves
Victoria O’Regan
By Victoria O’Regan
17 Nov 2021
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Load shedding is back, and was due to resume at 2pm on Wednesday. Stage 2 will be implemented until 5am on Saturday, the power utility has said.

After a brief respite from power cuts, Eskom announced that Stage 2 load shedding will be implemented from 2pm on Wednesday until 5am on Saturday. This is to preserve the remaining emergency reserves at the open cycle gas turbines and pump storage power stations in order to prevent higher stages of load shedding, the power utility said on Wednesday. 

“Due to the loss of Medupi, Kendal and Duvha units we now have insufficient generation capacity at our disposal, and as such, we have no alternative but to implement Stage 2 load shedding from 2pm this afternoon until 5am on Saturday,” said Eskom CEO André de Ruyter while delivering an update on the power utility’s current system challenges on Wednesday morning.




Eskom warned on Tuesday afternoon that load shedding could be implemented at short notice should there be further loss of generation capacity following the failure of five generation units at power stations throughout the day. 

In Tuesday’s statement, the utility requested “the public’s assistance in reducing the usage of electricity as the power system is severely constrained”. A generating unit each at Kusile and Majuba were taken offline to repair boiler tube leaks, while a generating unit each at Kriel, Majuba and Matimba had tripped, it said. 

Of the five units that failed on Tuesday, units at Majuba, Kriel and Matimba power stations have returned to service, Eskom said in a statement on Wednesday. The remaining two units at Majuba and Kusile are undergoing boiler tube leak repairs.

“Total breakdowns currently amount to 15,485MW while planned maintenance is 4,100MW of capacity,” it said. 

The unit at the Kriel power station was returned to service on Wednesday morning, said De Ruyter. However, at 5.45am unit three at Medupi tripped and another unit at Kendal was lost.

Eskom had also lost a unit at Duvha and it was not yet known when it would return to service, but “our crews are working flat-out on that unit”. 

“During the day we expect that Kendal unit four will return to service by 4pm. That is 640MW. However, we do have a number of units that are at high risk. This high-risk number totals 1,157MW,” said De Ruyter. 

The total risk of units where Eskom is operating with known issues and challenges is 6,345MW, he said. This was a high number, indicative of the inherent risks faced by Eskom. 

Eskom currently has eight open cycle gas turbines in operation. De Ruyter said this was “not desirable” since the turbines are intended to operate during peak periods only. “The continued high levels of diesel consumption are not desirable.”

Towards the end of the briefing, De Ruyter said: “We have a challenge with our remaining emergency reserves. Forecasting our projected diesel consumption has put us in a position where we are likely to deplete our diesel reserves too quickly, and that will create an undue amount of risk in the system and consequently we have to preserve emergency reserves.”

The implication of this is that Stage 2 load shedding will be implemented on Wednesday, he added. 

De Ruyter said that over the weekend Eskom intends to “take out” seven units at various power stations to address some of these challenges. 

“That means that we will take off 3,842MW. Demand over the weekend typically is significantly lower, so we don’t expect this maintenance programme to cause load shedding. But, of course, if we have further breakdowns the risks will remain.” 

Once the repairs had been implemented, Eskom “should be in a position to return after the weekend with replenished dam levels” and restored diesel levels. DM

 

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