Eskom will cut 2GW of supply from the national grid because it lost additional generating units overnight.
The company had earlier said it would cut 1GW through rotational blackouts, or load shedding, the Johannesburg-based utility said in a statement on its website on Friday.
Eskom announced on Twitter that it will implement stage 2 load shedding from 9am to 10pm on Friday.
Africa’s biggest power producer is struggling with declining demand, ageing plants and delays in new facilities as it takes steps to emerge from multiple scandals involving graft and mismanagement.
The company, which has been identified by ratings agencies as a key threat to South Africa’s economy, is discussing its turnaround plan with the department of public enterprises and President Cyril Ramaphosa.
First-half profit plunged 89% and the company’s debt burden is “impossibly high”, chairman Jabu Mabuza said this week. — Reported by Ana Monteiro, with assistance from Prinesha Naidoo