Eskom says that while it does not expect to have to implement load shedding on Friday, the country's generation system remains vulnerable.
"We are utilising emergency reserves to supplement generation capacity. We remind customers that as the generation system remains constrained, vulnerable and unpredictable, load shedding could be implemented at short notice if there is change in the generation system’s performance," the utility said in a morning power update.
Unplanned outages or breakdowns were at 10 755MW on Friday morning, while 5 567MW was offline due to planned maintenance.
On Thursday, Eskom said it was using emergency reserves as some generation units have been taken off the grid for emergency repairs.
The cash-strapped power utility has warned of an increased likelihood of power cuts over approximately the next 18 months as it conducts maintenance on its fleet of ageing power plants.