Eskom said it was prepared to introduce rolling blackouts this winter in some parts of the grid to prevent a complete system collapse, which would inflict far greater damage on the economy.
Chief executive Brian Dames said Eskom could not rule out 'load shedding', as scheduled power outages are known in South Africa, as the utility wrestles with soaring demand in the southern hemisphere winter against limited supply.
"We will take whatever measures we need. It means if we get close, we will drop the load. We will drop the customers and protect the country," Dames told a news conference on Monday, adding he would work to avoid system-wide problems "at all costs".
Eskom, which provides 95% of the country's power, has been walking a tightrope for five years as it tries to bring long overdue new power plants online after the system was brought close to collapse in 2008.