The Koeberg power plant will be operating at full capacity following repairs completed on Wednesday, said Eskom.

Eskom said unit two of the power plant had been shut down on 22 November. This was because the unit had been in need of repairs due to a "technical fault".

A complete shutdown was necessary for the repairs to take place.

As of Wednesday afternoon, unit 2 was operating at 75 percent of its capacity and was expected to be at full power at around midnight.

Eskom spokesperson Fani Zulu said that Koeberg coming back online had improved the power situation in South Africa.

"The reserve situation has improved, but we're still vulnerable. The underlying vulnerability is still there," he said.

Maintenance is done on Eskom power plants during the summer months but this is also the period when demand for power increases.

Zulu asked South Africans to watch their power consumption because "we have a low margin (of power)".