Eskom will be moving to stage 6 load shedding as from 6pm, it announced on Monday evening.

"We regret and sincerely apologise that stage 4 loadshedding will move to Stage 6 loadshedding as from 18:00 today, as a result of a shortage of capacity. This follows a technical problem at Medupi power station impacting additional generation supply," it tweeted.

To date, load shedding has been implemented up to stage 4. Stage 6 allows for up to 6 000MW to be shed from the national grid, about 12% of Eskom's nominal total capacity.

The announcement sent shock waves across social media, with "Stage 6" trending within a matter of minutes.

Eskom directed consumers to view load shedding schedules online and the City of Cape Town tweeted an updated load shedding schedule. At approximately 18:00, however, multiple municipal websites crashed, including the City of Cape Town, the City of Tshwane and the City of Johannesburg.

According to the tweeted schedule, some areas may experience 4.5 consecutive hours without power.

READ: Stage 5 and Stage 6 load shedding? Here's what you need to know

'Condemned to recession'

Economist Iraj Abedian tweeted that SA was now "condemned to recession", saying: "With Eskom confirming a Stage 6 black out from today, one thing is certain: the SA economy is now condemned to recession. Eskom too should be put into voluntary business rescue, politicians have proved their inability to grasp the severity of the problem facing our nation. Shame!"

Similarly, portfolio manager Wayne McCurrie tweeted that load shedding will further dampen growth prospects. "Stage 6 now. Truly catastrophic. Cannot expect any growth this quarter. Need new thinking at Eskom. I would rather have permanent stage 1 than go from full power to stage 6 within less than a week," he said.

Interim opposition leader, the DA's John Steenhuisen tweeted: "Stage 6 load shedding, uncharted territory, devastating for the economy and our country, fatal for growth and jobs. Time for government to level with South Africans about what is actually going on, I'm not buying this wet coal story!"

In an earlier power update on Monday Eskom had said that some of its power stations had started to flood due to heavy rains. On Friday, meanwhile, it announced that wet coal had contributed to a shortage of capacity.

In November 2019, Eskom chair Jabu Mabuza said there were at that stage no plans to load shed until March 2020. Mabuza was speaking at the power utility's interim results announcement. "We are not planning to load shed. We continue to be tight," Mabuza said.

The chairperson said at the time that Eskom's coal stockpiles had improved from 36 days in March to 54 days by the end of September. Only one station's coal stock remained below the minimum required, compared to nine understocked stations in March, he said.

In March 2018, however, Public Enterprises Minister Pravin Gordhan had warned of the seriousness of the power supply situation, noting that government announced that it was planning for the possibility of stage 5 and 6 load shedding. Eskom earlier announced that it would be expanding its load shedding plan to 8 stages, allowing for up to 8 000 MW to be shed from the national grid. Prior to that, only four stages were published that allowed for up to 4 000 MW of the national load to be shed.

In his weekly newsletter on Monday morning, meanwhile, President Cyril Ramaphosa said Medupi power station was "impressive" and a "symbol of the importance of our state-owned enterprises".

However, he said, "The problems with the construction of Medupi and its 'twin' Kusile account for much of the financial crisis at Eskom. There have been other factors, of course, not least of which are the effects of state capture, corruption, loss and shortage of essential skills and mismanagement."