Eskom said on Wednesday that the power outlook remained highly uncertain, with unplanned outages often varying by 2GW in one week.

Repeated breakdowns at Eskom’s coal fleet are a major brake on economic growth in South Africa.

The company with a nominal capacity of around 46GW has implemented scheduled power cuts on more than 30 days so far this year, more than in the same period last year when power cuts reached record levels.

At a news conference, Eskom said in its base case of 12GW of unplanned outages over the April-August winter months no days of scheduled power cuts were seen.

But in a scenario with 13.5GW of unplanned outages there could be 37 days of power cuts during winter and 104 days in a scenario with 15GW of unplanned outages.

More than 15GW of capacity was offline because of breakdowns at various stages this week.

Eskom will implement stage-2 power cuts from 5pm to 10pm on Wednesday after three generation units failed, requiring up to 2GW to be shed from the national grid.

Eskom generates more than 90% of South Africa’s power but has struggled to meet demand for more than a decade. President Cyril Ramaphosa’s government has promised to make the firm more efficient, but progress has been difficult.