Johannesburg - National electricity provider Eskom said on Friday it would effect a third day of rotational powercuts, saying it had lost supply from some generating units due to coal and ash handling issues.
Eskom, which had initially indicated it would scale down loadshedding to "stage 1", which involves suppressing 1,000MW of demand at any given time, said it would instead apply "stage 2" - in which it takes off 2 000MW - for the greater part of the day.
The state-owned utility said it had, since a media briefing late on Thursday, suffered a major setback by losing additional capacity from Medupi power station.
"Late last night, we lost Medupi 3, 4 and 5 due to coal and ash handling issues. This is in addition to the conveyor belt that failed on Saturday 12 October at the power station," the company said in a statement.
"This means that the power system has deteriorated further creating an additional shortage of about generation capacity of 1 500MW. As a result we will regrettably maintain stage 2 loadshedding for the greater part of today."
The powercuts have affected ongoing national examinations for students finishing high school this year.
"We understand the negative impact this will have on our customers, in particular our matriculants who are writing exams this morning. In order to lessen the disruption on exams, will be implement stage 1 loadshedding from 9:00 until 12:00 midday and thereafter revert to stage 2 loadshedding until 23:00," Eskom said on Friday.
Financially strapped Eskom, which supplies 95 percent of South Africa's electricity demand, imposed similar powercuts earlier this year, saying its units were struggling to keep up with demand.