South Africa has imposed rolling power cuts for the first time since 2008 as it struggles to cope with coal shortages and technical problems caused by recent heavy rains.
State-owned electricity firm Eskom said incessant downpours over the past week had flooded mines and left stockpiles too wet to use in its coal-fired power plants.
The company, which supplies about 95 per cent of the country's electricity, called on major industrial customers to reduce usage by at least 10 per cent, and domestic users to turn off swimming pool pumps, water heaters and other non-essential items.
It said power interruptions will be limited to two hours at a time.
"The whole country will be affected by load-shedding, but not every city or suburb will be affected by load-shedding simultaneously," spokesman Tony Stott told AFP.
Large companies and major hospitals resorted to generators and emergency power supplies on Thursday as the first cuts kicked in.
Flights at Johannesburg's main international OR Tambo airport were delayed and high-speed train services were partially suspended.
"We did experience a power outage. Our back-up power came on immediately and assisted us in terms of essential services but there were services that had to be operated manually and that resulted in some delays," airport authority spokeswoman Unathi Batyashe-Fillis told AFP.
South Africa last suffered widespread blackouts six years ago, causing factories and mines to close and costing the economy billions of dollars.
The crisis contributed to a credit rating downgrade, a sell-off in the rand and an outflow of investment.
The latest outages add to the country's woes at a time when it is lagging behind some of its African peers, with the central bank cutting its growth forecast to a four-year low of 2.8 per cent for this year.
The cuts also come just two months before crucial general elections in which the ruling African National Congress faces a stiff fight to retain power.
