Eskom has announced that stage 2 load shedding will be implemented at 21:00 on Saturday and will last until 05:00 on Monday.
The power utility said that if there was any further deterioration in the system, load shedding would be implemented earlier on Saturday.
"This load shedding is due to a failure of a generation unit each at Kusile, Medupi and Arnot power stations, as well as a delay of a unit returning to service at Tutuka power station," Eskom said.
"In addition to the above, the failure of the coal conveyors at Medupi led to reduced output at the station. While this has since been rectified, it will take some time to recover the full operations."
The was also a complete shutdown of the Kendal power station ash plant due to an electrical fault.
"This required the station’s output to be reduced to minimum. The ash plant has since returned to service, and the ash backlog recovery is in progress.
"These constraints, together with higher demand yesterday and today, have resulted in extensive usage of emergency generation reserves, which will have to be sufficiently recovered for the week ahead."
Total breakdowns have increased to 14 727MW while planned maintenance is 6 711MW of capacity.