"Today we lost three additional generation units and had to use our emergency reserves in order to meet demand throughout the day," state-run power utility Eskom said in a statement.
The stage 2 rolling blackouts started at 10:00 p.m. local time (2000 GMT) and would last until 05:00 a.m. Friday (0300 GMT), said Eskom, which provides more than 95 percent of the electricity consumed in South Africa.
The blackouts would allow Eskom to shed up to 2,000 megawatts of the national load per day.
"As a result, our emergency reserves are now at critically low levels, and need to be replenished overnight in order to meet tomorrow's forecasted demand in electricity," Eskom said.
Eskom has been working to avoid load shedding this week, as the electricity system is severely constrained.
South Africa has suffered from electricity insufficiency for years, while power blackouts have become increasingly frequent these days.
President Cyril Ramaphosa has repeatedly pledged to turn around the debt-ridden utility haunted by poor management and alleged corruption.
The government has forked out billions of rands (1 rand equals 0.068 U.S. dollars) to bail out the cash-strapped utility, but has little effect.
Load shedding costs the country billions of rands a day and trillions over the years.
"Stage 2 loadshedding was terminated at 05:00 this morning. While the system remains extremely constrained and vulnerable, the overnight loadshedding assisted with partial recovery of our emergency resources to enable us to get through the morning, " Eskom said on Friday.
"We will need to continue to replenish both our water levels at pumped storage schemes and diesel for our open cycle gas turbines over the weekend in order to place us in a better position to stabilise for the week ahead.
"Our objective remains not to implement loadshedding during the day today, however given the unplanned breakdowns that are still above 10 500 MW and the need to continue to replenish emergency reserves, the probability of loadshedding remains high for the latter part of the day but will only be implemented if absolutely necessary. Eskom will communicate an update later today.
"Eskom’s technical teams are working tirelessly to return units from planned and unplanned maintenance and to replenish emergency reserves."
*Tuesday, 05 November, *Moody’s Investor Services (Moody’s) has downgraded to ‘B3’ from ‘B2’ the long-term corporate family rating (CFR) of Eskom; the zero coupon eurobonds rating has similarly been revised to ‘B3’ from ‘B2’ in line with the CFR and the global medium term note (GMTN) programme and the senior unsecured GMTNs of Eskom were downgraded to ‘(P)Caa1/Caa1 from (P)B3/B3.
Outlook remains negative.
Moody’s has simultaneously affirmed the Baa3 rating on Eskom’s government guaranteed notes.
Eskom notes with disappointment the ratings decisions implemented by Moody’s. ■