Eskom says challenges at four power stations are making it difficult to supply the country’s demand for electricity.

Jan Oberholzer, Eskom’s chief operations officer, said the power stations were Kusile, Majuba, Tutuka and Kendal. This comes as the power utility announced a fresh wave of load-shedding –  stage 2 from on Wednesday to Monday morning.

“The unit we didn’t expect to give us challenges is Kusile. For the past five days we have had no units running,” Oberholzer told a media briefing. 

Group CEO Andre de Ruyter said they are working hard to bring units back as quickly as possible and hope to be able to reduce the extent of load-shedding.

“Because we have had some challenges on our generation system, we have depleted our emergency reserves to the point where we risk not having an adequate backup supply in the event of further failures of our generation system,” said De Ruyter.

Eskom has experienced a number of breakdowns since last Friday, Oberholzer said.

“About 4,000MW was lost due to breakdowns, full load losses and partial load losses that immediately placed us where we are today,” he said.

The utility did not have sufficient generation capacity to meet demand and that necessitated the use of extensive emergency resources – water and pump storage and diesel.

“We then continued to have further breakdowns and delays in returning some units until on Wednesday [Tuesday], when we had further breakdowns,” Oberholzer said.

“At 7am we had the following levels at our pump storage facilities: At Drakensberg we had 81 generation hours but we had 38 pumped hours, meaning it would take us 38 hours of pumping to replenish that battery and fill it to its full capacity.

“Similarly, at Ingula we had 41 generation hours at that plant but 22 pump hours and ideally you want pump hours to be low as possible,” De Ruyter said.

“What we would do is replenish pump storage overnight from our coal-fire plant, where demand is low, but because of the poor performance of our coal-fire generation, we have had to run diesel to replenish our pump storage, which is very expensive,” he said.

According to De Ruyter, diesel remains a major concern, worsened by the 80c a litre increase in the price this week.

He said immediately before the increase in the diesel price, supplies had generally run low.

De Ruyter said the reserves need to be replenished to protect the system against total blackout.

“The shortage of generation capacity is worsened by two issues. The first is the loss of 720MW capacity following the explosion of hydrogen in a power generating unit at Medupi 4.

“That plant is in repair. We anticipated it will take until the end of next year to fully complete at a cost of about R2.5bn. The loss of that generation capacity adds to the constraints we are facing.

“Second, we have taken out unit 2 at Koeberg on a planned outage to do two things. The first is to refill. Nuclear plants consume far less fuel in terms of weight and volume than coal fire plants.

“They consume nuclear fuel and this needs to be replaced from time to time. Typically these outages take about 100 days or so to replenish the fuel and we also do related maintenance during this period,” he said.

He said the power utility is also replacing three steam generators at Koeberg 2.