The National Energy Regulator of SA (Nersa) has conceded it had made calculation mistakes when it approved tariff increases for Eskom, a move that could see consumers throttled by a 15% electricity tariff increase next year, according to Rapport newspaper.

Eskom on Wednesday proposed in a virtual court hearing that tariffs be increased by 15% next year instead of the 5.22% that had been approved by Nersa, the Afrikaans Sunday paper reported.

This would mean an increase five times the inflation rate.

But Nersa has asked the judge to refer the matter back to the body so it can fix its calculation mistake, instead of having the courts decide on the matter.

Judgment was reserved.