Africa's most industrialised economy is set for its worst year of electricity outages, despite President Cyril Ramaphosa pledging new moves to tackle the crisis in July.
State-owned Eskom implemented extensive power cuts last week and is scheduled to do so again this week.
"We have various plans in place, I believe very good plans...however this is going to take time to implement," Eskom Chief Operating Officer Jan Oberholzer said, adding: "For the next 12 months or so we may not see the required benefits."
Oberholzer told a news briefing that the performance of Eskom's fleet of ageing, unreliable coal-fired power stations continued to deteriorate. He said 42 generating units, or almost 24,000 megawatts of capacity, tripped last week, with some units breaking down more than once.
Mid-way through its financial year, Eskom has spent 7.7 billion rand ($451 million) on diesel to run emergency generators, far in excess of the budgeted amount, Oberholzer added, calling it a serious concern.
"It's really a difficult situation we find ourselves in," he told reporters.
(Reporting by Alexander Winning and Anait Miridzhanian; Editing by Alexander Smith)

Power lines run from state power supplier Eskom to the national grid, in Johannesburg, South Africa, 27 July 2022. EPA-EFE/KIM LUDBROOK