Electricity Minister Kgosientsho Ramokgopa has attributed the current round of Stage 6 load shedding to ramped up planned maintenance overlapping with unplanned breakdowns at several power plants. By the end of the week, however, lower stages of load shedding are anticipated.
The minister and Eskom officials on Tuesday gave an update on the status of the grid, after the power utility announced it would implement Stage 6 load shedding until further notice.
“[The] Stage 6 load shedding [we are] experiencing now is largely due to us ramping up planned maintenance and unplanned capacity loss factors,” Ramokgopa said.
As at Tuesday, 5 September, unplanned breakdowns were at 17 297MW, with planned outages for routine maintenance being around 5 467MW. The peak demand forecast is around 28 303MW, while the actual available capacity is 25 060MW.
Pumped Storage Reserves
Eskom head of generation Bheki Nxumalo said that by the end of the week, pumped storage reserves will have likely recovered, enabling lower stages of load shedding. The higher stages of load shedding had been sparked by low reserves, he explained.
“When we were starting to recover, we had additional units break down late Sunday evening and yesterday,” he said. These were units at Medupi, Lethabo, Kriel and Duvha.
It caught us when the reserve was at its lowest … and we did not get enough time to recover.
Nxumalo also unpacked exactly what went wrong at some units – with breakdowns being unsafe to repair immediately. For example, a unit at Medupi on Monday morning saw an ash-carrying chain break underneath a boiler. Eskom’s team had to wait for the boiler to cool down before they could do any repairs. Matla also experienced breakdowns that warranted waiting for boilers to cool down. Duvha has faults with gas air heaters – based on the location of the issue – the units need to be taken offline, Nxumalo said.
Risk of Load Shedding with Ramped-Up Maintenance
During the briefing, Ramokgopa explained that units taken out for planned maintenance during the winter period were capped at 2 500MW. The power utility also relied on running the open-cycle gas turbines on diesel, in order to limit load shedding during this period. The cost of diesel spent over four months came to about R12.4 billion, News24 previously reported.
Eskom has slowly been ramping up its planned maintenance and, on 30 August, took over 6 000MW offline. While this has the long-term benefit of improving the resilience of the system, there is a risk that an overlap with unplanned breakdowns would warrant higher stages of load shedding – which has happened.
Ramokgopa said that in the past, the country did not follow its planned maintenance strictly, which was also because Eskom had limited funding. That contributed to the failing performance of units. But the fiscal support from Treasury – namely taking off R254 billion of Eskom’s debt – has freed up funding for maintenance, which the power utility does not want to compromise on.
Planning Around Events
Responding to a question about whether Eskom had been running plants harder during the BRICS summit in August, Nxumalo said that was not the case. “We do not plan around events; we plan around the system and what is required,” he said. He also added that the machines are run according to their design limitations.
A similar approach will be taken with the upcoming Rugby World Cup. “How we manage the system is devoid of major events,” said Ramokgopa. “We want to protect the system, we want to improve generating capacity … Load shedding is an instrument at the disposal of the system operator to make sure we address demand and generation. If demand exceeds generation, there will be load shedding,” he added.