South Africa’s energy regulator apologised for a R54-billion error in calculating electricity tariffs, a mistake that will be passed on to consumers.

The National Energy Regulator of South Africa, which determines what State power utility Eskom can charge for electricity, announced the miscalculation last month, without providing further details.

On Wednesday, it put the blunder down to a “data input error” that was picked up by Eskom, according to a presentation to lawmakers.

While the mistake had been identified before the tariff determination was made in January, it wasn’t rectified as indicated at the time, and only discovered five months later, the regulator said.

“The error is regrettable; it should not have happened,” it said.

The incident brought into the spotlight South Africa’s surging electricity prices and will result in them increasing by 8.76% in the next financial year, instead of the 5.36% originally agreed, and by 8.83% the year after, compared with 6.19%.

That adds to an eightfold surge in South African electricity costs since 2008, according to the Energy Intensive Users Group, whose members including Anglo American and Glencore account for about 40% of the nation’s electricity consumption.

The EIUG has called for a review of the January tariff decision and asked Nersa to consider its pricing methodology and implementation.

‘’This error by Nersa has been a big blow for the affordability of electricity in this country,” Electricity Minister Kgosientsho Ramokgopa said in an interview.

“Because of it, we have to rethink our overall strategy” on power provision, he said.