The Koeberg nuclear power station, outside Cape Town.

Cape Town - A human error that caused Koeberg Nuclear Power Station to trip one of its two reactors has cost Eskom R200 million in a week, according to a power industry specialist.

The accident has further cost the country’s economy R7.5 billion, power industry specialist Chris Yelland said on Tuesday.

However, economist Mike Schussler has taken a more conservative approach, saying that in a worse case scenario Stage 1 load shedding would cost the country around R6bn every month. “Double that for Stage 2 and double it again for Stage 3.”

He said while the effects of rolling blackouts would not be crippling, they would have a hugely negative impact on the economy and the GDP would take a hit.

Eskom spokespeople could not be reached for comment by the time of going to press.

Yelland said the Sunday before last, part of some scaffolding erected for maintenance work touched a neutral bar from a transformer on the reactor, causing the unit’s automated safety system to register an “earth fault” and shut the reactor down. “From what I understand from Eskom, the scaffolding touched a neutral bar, not a live contact. If it had been a live contact, there would have been serious consequences and whichever workers were involved would have been killed,” he said.

“But when it touched the neutral bar, the unit read it as a restricted earth fault and the automated safety system shut the reactor down immediately. “If this did not happen, there would have been nowhere for the energy generated by the reactor to go and the temperature inside the reactor would have soared immediately,” Yelland said.

When a reactor overheats, the result is a meltdown, which has disastrous consequences similar to a nuclear explosion.

”The fact is, Koeberg did exactly as it should have by shutting down the unit. This proves that the systems work properly,” Yelland said. But the result now is economic damage.

“The unit is now shut down until May for scheduled maintenance, so one cannot count it as a cost to the economy. But it was down for a week unscheduled and if you take the delivery of electricity at R100 a kilowatt-hour at 900MW for 12 hours over seven days, it comes to a loss of R7.5 bn,” Yelland said. “To replace the loss, Eskom has had to run its open cycle gas turbines on diesel at a cost of R3.50 per kW/h for 12 hours a day for seven days.”

Yelland said Stage 1 load shedding of 10 hours a day over 20 days a month cost the country R20bn a month. Stage 2 worked out at R40bn and Stage 3 R80bn. That was without the long-term costs of job losses: stunted economic growth, less investment and a general loss of confidence in the country’s government and economy.

Schussler said while many businesses were planning around the schedule, for example factories starting production earlier or later in the day, companies were still losing money. Running generators and changing shifts had become new costs for businesses to navigate. He said a total blackout would be the real “killer” for South Africa’s economy.

“So as long as there is certainty, and we have a set schedule, businesses can plan around load shedding.”

Cape Argus