The risk of load shedding would be heightened next month as State-owned power utility Eskom takes half of the Koeberg power station’s capacity off line for general maintenance.

An Eskom spokesperson told Engineering News Online on Friday that, while the grid was continually constrained, next month’s scheduled maintenance on one of the two 900 MW units at the Cape Town nuclear power station raised concerns over the utility’s ability to keep the lights on during the period.

Eskom was planning to set a date for the maintenance next week.

However, the utility said it was in the process of bringing a number of generators back on line following maintenance and repair work, noting that this could alleviate the increased pressure on the national grid.

This emerged after Eskom issued its latest state of the power system update warning of increased demand next week Monday through Wednesday.

Demand was expected to outstrip capacity once again; however, Eskom assured that this did not increase the risk for load shedding, unless an unexpected loss of generators occurred or there was extra load or faults in the system.

The 28 497 MW to 30 549 MW capacity available from Friday through to Sunday was expected to meet forecast demand of between 27 726 MW to 29 603 MW.

The normal weekend demand slump would quickly be followed by a demand spike on Monday, Tuesday and Wednesday, when demand was expected to jump to 30 388 MW, 30 577 MW and 30 555 MW respectively.

This would be higher than the capacity, including open-cycle gas turbines, of 29 291 MW available on Monday and 29 827 MW and 29 860 MW on Tuesday and Wednesday respectively.

A spokesperson explained that a similar supply/demand scenario had occurred last week, but load shedding was averted owing to increased generating of power through diesel sources and the return to operations of units under maintenance.

A number of generators were expected to return to operation next week, alleviating some of the demand pressure.