10.08.13.A sunset shot of the Koeberg nuclear power plant next to Melkbosstrand near table View. Picture Ian Landsberg

Johannesburg - Even though Eskom has tried to avail more units for power generation this winter, South Africa will remain vulnerable to load shedding for as long as new power stations do not come to the party.

Azar Jammine, the chief economist at Econometrix, yesterday said that even if Eskom had more resources this winter, the fact that its power stations were old made it vulnerable to unexpected problems.

“I’m not suggesting that [load shedding] will remain in place for a long time but we are vulnerable to it all the time. When you have such a small margin between demand and supply, any unexpected shutdowns bring you to a crisis mode,” said Jammine.

On Wednesday night, the power utility implemented another period of rotational load shedding in the second episode this year after five years of averting blackouts.

Two units at Duvha and Kendal power stations respectively had tripped and a portion of the electricity that it imports from Cahora Bassa became unavailable. A load-shedding schedule was implemented between 6pm and 8pm. While the company withdrew it hours later, it declared an emergency yesterday and said that if demand did not decrease, load shedding would be implemented again as a last resort.

Eskom had 35 005 megawatts of supply available last night while the evening’s peak demand was forecast at 35 147MW. Any extra faults in the system like the tripping of a unit would bring back the need for the load-shedding protocol, Eskom said.

“The rest of June and July is expected to be similar to what we’re currently experiencing. The demand is high for a short sharp evening peak and vulnerable to failures [even short term] over peaks,” Eskom said in response to queries.

The utility said that on Wednesday night it had used all its available demand response contracts of about 1 000MW with its customers.

With a supply emergency declared, this would have been used again yesterday since the emergency status required industrial customers to immediately reduce their consumption by 10 percent.

Johan Muller, the programme manager for energy and environment at Frost & Sullivan Africa, said with the economy moving into a negative growth direction, even one day of electricity disruptions to businesses was one day “too often”.

“South Africa as a country needs to have all sectors operating at full capacity, including the industrial, commercial, residential and agricultural spaces,” he said.

Like Jammine, Muller predicted more load shedding during this winter. He also pointed out that the new Medupi power plant had suffered delays. “This results in a very tight system indeed. Planning becomes very problematic.”

He pointed out that the power utility’s reserve margin, which typically fluctuated between zero and 5 percent, compared to the global standard of 15 percent, significantly increased vulnerability.

Eskom said it was now getting about 450MW from short-term independent power producers. It was negotiating to increase this by 500MW before the end of the year. - Business Report