Eskom CEO Brian Damas (L) and Eskom Chairperson Zola Tsotsi speak during a load shedding press conference held at Eskom Megawatt park in Sunninghill. Picture:Paballo Thekiso

South Africa’s power supply is on a knife edge again and the state’s electricity supplier, Eskom, is begging consumers to turn it off to avoid disaster.

On Thursday morning, the power grid hit a massive crisis level - 3 000 megawatts (MW) of electricity had to be shed as Eskom lost four power generating units at Kendal power station in Mpumalanga due to wet coal and lack of emergency reserves.

Power cuts caused chaos in many cities with streets gridlocked as traffic lights went out. Parts of Joburg were out for up to six hours.

When he saw consumers were using up the last of several thousand megawatts, Thava Govender, Eskom’s divisional executive of generation, “knew we were in trouble”.

“If you are running a system on a knife edge like we do you know anything can happen. This week was wet coal and next week it could be something else,” he said. “When an incident takes four units out you know there is trouble coming. At 1am it was clear in my mind what we needed to do to avoid collapse.”

Govender summoned a crisis committee meeting at 4am and chief executive Brian Dames decided to move to planned power cuts straight on stage 3 - one of the utility’s highest stages or 20 percent of demand. This was last reached in January 2008.

Stage 3 allows for load shedding of up to 4 500MW, with a maximum of three cuts per area in 24 hours, and a maximum of two-and-a-half hours per cut, but Eskom said some municipalities like Joburg opted for four hours.

The grid was plunging into another emergency - much bigger than that seen in November and February. The lines feeding homes were bottlenecked - Eskom had only 27 000MW capacity and demand was reaching for 30 000MW.

“This was a painful yet necessary decision to protect the electricity power system from a total blackout,” said Dames yesterday.

“A total blackout would have significant consequences for the South African economy. While we are committed to providing early warning, this was the earliest we could communicate as the system status changed rapidly in the early hours of (Thursday).”

But Dames insisted Eskom was in a better position than in 2008 to manage the situation.

“The system will remain tight and vulnerable for the next few years until substantial part of Eskom’s build delivers more capacity,” he warned. “Last year’s power demand was slightly lower than this year around the same time. On average we now have difference of about 1 000MW. At the end of March the 900MW Koeberg unit will come out for maintenance.” He urged people to aim at saving 10 percent.

Heavy rain has soaked tons of coal feeding power stations in Mpumalanga.

Dames said wet coal clogs up everything. A conveyor belt fire in December meant suppliers to Duvha power station had to use road transport.

He said the blackouts had ceased from 10pm on Thursday.

Saturday Star