Johannesburg - Eskom is implementing stage three rolling blackouts which will last throughout the weekend, it announced on Friday.
There would be load shedding until 10pm on Friday, Eskom said in astatement.
Power cuts would begin at 6am and end at 10pm on Saturday. On Sunday it would begin at 8am and end at 10pm in order to build up reserves for the upcoming week.
“Our objective for load shedding this weekend is to fill the pumped storage dams, fill diesel tanks and undertake essential maintenance,” Eskom chief executive Tshediso Matona said.
“Our aspiration after that is to avoid load shedding if at all possible until mid-January.”
The power utility could not guarantee that but it would put in every effort over the festive season to avoid interruptions, he said.
Due to technical problems at its power stations, depleted water reserves and logistical issues relating to diesel supplies at its peaking power stations, Eskom's power system was extremely constrained, the parastatal said.
As a result stage two power cuts were implemented on Friday at 11am. It was extended to stage three at 12.05pm.
“The change in stages is due to the shutdown of two of our open cycle gas turbine power stations which use diesel to generate electricity,” Eskom said.
“The diesel reserves have been depleted at the Gourikwa and Ankerlig gas turbines leading to the shutdown of the power stations.”
This in turn led to the Drakensburg and Palmiet pumped storage schemes, which use water to generate electricity, to reduce their output as a result of depleted water reserves, Eskom said.
Stage one allowed for up to 1000MW of the national load to be shed, stage two for up to 2000MW and stage three for up to 4000MW.
“A further 1000MW of capacity is offline after three coal-powered units tripped last night due to technical faults,” it said.
The Ekurhuleni municipality said the rolling blackout schedules on its website would no longer be applicable as Eskom had taken over the process after reaching stage three.
“ (The municipality) has been informed that Eskom is now in total control of the load shedding process,” spokesman Themba Gadebe said in a statement.
“The Ekurhuleni load shedding schedule on its website at www.ekurhuleni.gov.za is therefore currently not applicable.”
Planned power cuts had started in the area around 11am.
The Nelson Mandela Bay municipality also said rolling blackouts started in the area at 11am on Friday.
It was highly probable there would be blackouts over the weekend, the municipality said in a statement.
On Friday, the City of Johannesburg and City Power said it would remotely switch off geyser control systems to certain areas to manage electricity control across the city.
The city also appealed to its “large power users and key business customers” to reduce their usage of electricity by switching off non-essential machinery and appliances such as air conditioners and lighting.
“City Power also requests domestic customers and medium and small enterprises to reduce their electricity consumption by switching off non-essential appliances, such as office and basement lights, where possible.”
Eskom said on Thursday that the electricity system would be under severe strain at the weekend, and it asked municipalities to reduce demand by cutting power to their customers.
Eskom, City Power and the City of Johannesburg said customers should visit their websites to confirm the rolling blackout schedule, and should have torches and lanterns at hand to light up their homes.