Eskom, which provides about 95 percent of the South Africa’s electricity, implemented power cuts yesterday amid maintenance problems. The rand weakened as investors fretted about the effect on economic growth.

Power shortages have been a major constraint on output in Africa’s most industrialised economy. Protracted outages could cost the country its last investment-grade credit rating from Moody’s Investors Service, which is due to deliver its next assessment on November 1.

The government has said it will announce plans to restructure Eskom into three operating units and reorganise its debt by the end of the month.

“The timing isn’t great,” said Simon Harvey, a London-based currency analyst at Monex Europe Ltd. “Whether this is a short-term reaction from Eskom to stem longer-term supply issues or is the start of a continuous process is key and will determine if the rand’s sell-off is more structural. Regardless, investors won’t take the news well.”

The power cuts were likely to last from 09:00 to 23:00 local time, Eskom said in a Twitter posting, without specifying whether this was a one-off or the start of a new round of rolling blackouts.

The utility, which has amassed R450 billion of debt and is reliant on state bailouts to remain solvent, has battled to meet demand for electricity because most of its plants are old and have been poorly maintained.

‘Extremely constrained’

“The electricity system has been extremely constrained this week,” due to unplanned plant breakdowns, Eskom said. “We unreservedly apologise to South Africans for the negative impact this may have on them and want to ensure the nation that we continue to work tirelessly to ensure security of energy supply.”

The rand slumped as much as 1,1 percent before paring the decline to trade 0,7 percent weaker at R14,98 per dollar by midday.

Yields on benchmark 2026 government bonds climbed six basis points to 8,29 percent. South Africa has experienced intermittent power cuts since late 2005, with the previous round occurring more than six months ago.

Eskom attributed the latest outages — it had to cut 2 000 megawatts from the national grid — to boiler tube leaks at five of its generating units and the breakdown of a conveyor belt used to supply coal to its Medupi plant.

Pumped storage and open cycle gas turbine facilities had been used extensively due to shortages of generation capacity from its coal-fired plants, lowering dam levels and diesel supplies, it said.

“The announced blackouts should be a very strong incentive for the administration to urgently address prevailing issues at Eskom,” said Piotr Matys, a currency strategist at Rabobank in London.

“It is absolutely critical that a comprehensive and credible restructuring plan is quickly implemented, not only to avoid more blackouts in the future that seriously undermine economic activity, but also to reduce the risk of South Africa being downgraded to junk by Moody’s.”  — Bloomberg.