Johannesburg - The power grid is extremely constrained and will remain so for the rest of the summer, Eskom said on Tuesday afternoon.
It called on consumers to switch off geysers, air conditioners, pool pumps and all non-essential appliances throughout the day to reduce electricity demand.
Eskom promised South Africans that it would not move to stage 3, after implementing stage 2 load shedding on Tuesday, "unless it is absolutely necessary".
Eskom implemented stage 2 load shedding at 11:30, after announcing stage 1 load shedding from 10:30 to 22:00, the power producer said.
"At our pumped storage schemes (which use water to generate electricity), the dam levels are low because we were not able to pump the water back to full capacity over the weekend," said Eskom.
"This is a result of us having to use our pumped storage schemes over the weekend to meet demand. Ordinarily, the weekends are used to pump our dam levels to maximum capacity in preparation for the forecasted increased demand in electricity during the week."
Eskom request workers to switch off the lights, with the exception of security lighting when they leave office buildings Tuesday evening and to ensure that air-conditioners are switched off over night.
"Commercial customers, particularly shopping centres and office blocks, can make the biggest difference by switching off non-essential lights and not to leaving office equipment such as photocopiers and computers in standby mode after hours," said Eskom.
Earlier on Tuesday Eskom spokesperson Khulu Phasiwe confirmed the utility was escalating blackouts from stage 1, implemented earlier on Tuesday morning, to stage 2.
Stage 1 allows for up to 1000MW of the national load to be cut, stage 2 for up to 2000MW, and stage 3 for up to 4000MW.
Phasiwe said Eskom would release a statement on the power cuts later on Tuesday.
"Eskom will implement load shedding stage 1 from 10:30 today. It is likely to continue until 22:00. We will give updates throughout the day," Eskom tweeted shortly after 09:00.
Earlier, Eskom spokesperson Andrew Etzinger warned there was a good chance of further power cuts.
"The grid is exceptionally tight. There is a medium to high chance of load shedding today [Tuesday] if we do see further technical challenges developing."
"We won't go to stage three unless it is absolutely necessary."
Grid 'exceptionally tight'
Acting chief executive of Eskom Dan Marokane said in a statement: “As previously indicated during our quarterly state of the system briefing on 15 January, the grid will be under pressure for the current week resulting in a high risk of load shedding.”
"The grid is exceptionally tight. There is a medium to high chance of load shedding today [Tuesday] if we do see further technical challenges developing," spokesperson Andrew Etzinger said.
He said 25% of Eskom's generator capacity is not operational due to technical problems. He could not confirm or deny whether the power utility would need to implement stage three of power cuts.
"We will implement the stage necessary in order to protect the grid. We won't go to stage three unless it is absolutely necessary."
Eskom on Monday announced on Twitter that it had moved its power cuts from stage one to two.
"Load shedding has moved from stage 1 to stage 2 as of 3pm," it tweeted.
Power cuts would continue until 22:00, it said at the time.
It said the power system is severely constrained due to unforeseen technical problems at power stations.
This week's forecast:
Eskom's estimate for future load shedding:
Customers supplied by Eskom directly can search for schedules here.
Customers supplied by local municipal authorities can click here based on location*:
City of Cape TownBuffalo City MetropolitanNelson Mandela Metropolitan
Mangaung (Centlec)Load Shedding groups
Load Shedding time slots
City of Tshwane
Ekurhuleni MetroeThekwini (Durban)
Stage 3 schedules
Umjindi Municipality (Baberton)
Kimberley - Sol Plaatjie
The Durban CBD is at a stand still after Eskom implemented stage one of load shedding this morning.— SABC News Online (@SABCNewsOnline) January 27, 2015
Stage2 load shedding will continue until 22h00. We appeal to customers to reduce their electricity usage as it will ease pressure on system— Eskom Media Desk (@Eskom_MediaDesk) January 27, 2015
URGENT NOTICE: Please note that as of January 27, 12:00 noon LOAD SHEDDING STAGE TWO will be in progress. Please... http://t.co/YXTPLEy8N3— eThekwini Muni (@eThekwiniM) January 27, 2015
LOADSHEDDING ALERT: Stage 2 - Area 1 (Bellville) and Area 12 (Athlone, Manenberg). Start time 12:00 End time: 14:30 http://t.co/KxqinMmQUz— City of Cape Town (@CityofCT) January 27, 2015
Folks, this is it. The new normal. It ain't loadshedding, it's life. Quit whining and make a plan because Eskom doesn't really have one.— Alexander Parker (@thealexparker) January 26, 2015
Sooner or later Eskom will tell us load shedding was caused by Khanyi Mbau trying to use the Lobola calculator app.— Chester Missing (@chestermissing) January 26, 2015