150711. Sunset in Crownmines, Johannesburg. The picture can be used for Eskom energy supply crisis. Picture: Dumisani Sibeko

Johannesburg - South Africa found itself on the brink of more blackouts last night as Eskom forecast that the country’s electricity demand would outstrip its available supply by 811 megawatts (MW), creating a shortfall equal to almost half the capacity of its Koeberg nuclear power station.

Eskom had 32 500MW of supply capacity to meet yesterday evening’s peak demand, forecast at 33 311MW.

The same occurred on Tuesday and Wednesday when available capacity was less than forecast peak demand by 849MW and 144MW, respectively.

Unlike in the past, Eskom cannot count on large industrial users to bail it out this time around. As a result it issued a warning that it could not rule out another round of load shedding.

“Eskom will utilise all necessary emergency resources at its disposal, but should the demand not decrease, load shedding will be implemented as a last resort to protect the national grid from a total shutdown,” a communiqué to the media and customers read.

It is just over two months since Eskom brought back rotational load shedding, which saw mining companies forced to cut their electricity use by 20 percent for one day – on March 6. It could take further rotational load shedding to stabilise the national grid as big users have objected to bailing out Eskom.

“We’ve worked out a better arrangement with Eskom. We spent a lot of time to find an approach that will ensure large users are not affected differently,” Mike Rossouw, the chairman of the Energy Intensive User Group (EIUG), said.

The group took a stand last November when Eskom declared a supply emergency for more than one day, during which big industrial users had to heed the call to reduce their normal consumption by 10 percent. The EIUG said it was unfair of Eskom to place the burden of reducing demand only on industrial users.

He said the only users likely to have reduced their consumption yesterday were those with standard load reduction contracts with Eskom.

Eskom spokesman Andrew Etzinger said some of its industrial users had voluntarily reduced their power usage by 400MW by 5pm yesterday. This was over and above the capacity that Eskom was able to interrupt at BHP Billiton under the agreement between the two.

“The critical hour is between 6pm and 7pm, then demand reduces quickly. It’s easier to manage that than the summer peak because it’s only one hour. Our agreement with BHP is well suited for that.”

It needed voluntary savings of at least 10 percent from residential customers during this hour to manage demand.

The tripping of units due to boiler tube leaks and poor coal quality as well as the shutdown of Koeberg’s Unit 2 is what plunged Eskom into the chaotic situation as it pushed unplanned outages up to 8 500MW.

In previous weeks, unplanned outages did not reach 6 000MW, and stayed around 4 000MW in summer months.

Koeberg’s Unit 2 was shut down for refuelling and maintenance. Etzinger said it was expected to come back on stream next week. He said Eskom lost about 500MW of capacity due to poor coal quality. - Business Report