Johannesburg – Eskom announced on Friday that it had implemented stage three rolling blackouts that would last until 22:00 on Sunday.

It said power cuts would begin at 06:00 and end at 22:00 on Saturday.

On Sunday load shedding would start at 08:00 and it would also last until 22:00 to build up reserves for the upcoming week.

Eskom chief executive Tshediso Matona said: “Our objective for load shedding this weekend is to fill the pumped storage dams as well as the diesel tanks and undertake essential maintenance.

“We’re trying to avoid load shedding if at all possible until mid-January.”

Logistical issues

The power utility could not guarantee that, but said 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 at 11:00 on Friday and it was extended to stage three an hour later.

“The change in stages is due to the shutdown of two of our open cycle gas turbine power stations that 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.

No longer applicable

Stage one allowed for up to 1 000MW of the national load to be shed, stage two for up to 2 000MW and stage three for up to 4 000MW.

“A further 1 000MW of capacity is offline after three coal-powered units tripped last night [on Thursday] 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,” spokesperson Themba Gadebe said in a statement.

“The Ekurhuleni load shedding schedule on its website at is not currently applicable.”

Planned power cuts had started in the area around 11:00.

The Nelson Mandela Bay municipality also said rolling blackouts started in the area at about 11:00 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.

Severe strain

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 earlier 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.