By Olivia Kumwenda-Mtambo
JOHANNESBURG (Reuters) - South Africa's electricity supply was stable on Wednesday but the grid in Africa's biggest economy remained severely constrained, power utility Eskom said a day after it declared a power emergency for the first time in five years.
Some of the state-owned utility's ageing generating units unexpectedly tripped on Tuesday, while others were down for maintenance, forcing the company to admit it may have to introduce rolling blackouts as happened in 2008.
"We are constantly reviewing the situation and will lift the emergency notice once the situation improves," the utility said in a statement.
The power situation is impacting industry and the Energy Intensive User Group of Southern Africa (EIUG), which represents 32 mining and manufacturing companies, said its members had reduced power usage as requested.
"The question to Eskom is how long is this going to last and to what extent would other consumers equally share the burden?" said EIUG Chairman Mike Rossouw. Eskom had urged key industrial customers to cut consumption by 10 percent.
Mining group BHP, Eskom's biggest customer, had cut power to its aluminium smelters in line with an agreement to stabilise the national grid at times of stress. It receives no compensation for the disruption.
Bullion producer Gold Fields said it halted hoisting for several hours at its South Deep operation.
Eskom spokesman Andrew Etzinger said some of the generation units under scheduled maintenance should return to service on Wednesday, which should ease pressure on the grid.
The group said power supply would remain "extremely tight" for at least a week as it tries to bring tripped units and those under maintenance back online.
It also published provisional schedules for "load-shedding", as rolling blackouts are known, hitting a raw nerve with South Africans who had to endure weeks of disruption in a 2008 power crunch.
"You can't run a business without power. In 2008, I had to go out and buy a generator which cost me $30,000, but you can't actually run your business on that," said John Kullman, who runs an events and exhibitions firm.
More blackouts could also hurt the ruling African National Congress in a next year's election if voters believe it has underinvested in essential infrastructure since the end of apartheid.
The 2008 power crunch, blamed on Eskom's creaking chain of power plants, forced the closure of mines, factories and smelters for days, costing the economy billions of dollars in lost output.
Eskom, which provides 95 percent of South Africa's electricity, is now racing to bring long-overdue power plants online.
Medupi, one of Eskom's new coal-fired plants, is expected to deliver its first power in the second half of next year after a delay of at least six months caused by labour unrest and what Eskom has called the underperformance of contractors.
Another plant, Kusile, is expected to come onto the grid in December 2014.