Power cuts rolled out across the country on Monday as Eskom tried to load-shed after planned and unplanned power-station maintenance resulted in an electricity supply shortage.
Eskom had to shed 1 000MW, although this could go as high as 1 500MW, said general manager of demand-side management Andrew Etzinger.
He said maintenance had left 10 000MW out of service on Monday morning, when demand was usually in the region of 31 000MW.
Another factor playing a role was the shortage of diesel in the Western Cape, which was affecting the operations of the gas turbines, or small power stations located there.
These could generate about 1 000MW and were normally used to avoid load shedding. However, they were not operating, said Etzinger.
He said the highest demand of the day was usually experienced during the evening peak between 6pm and 8pm at 33 000MW.
Eskom’s electricity reduction agreements with industrial consumers could reduce this to about 32 000MW.
”We need to load-shed when demand exceeds supply,” said Etzinger.
After the morning peak, demand usually climbed towards lunch-time and again in the evening as people arrived home, switched on appliances and began cooking dinner.
”Supply is variable,” he said.
In winter demand could reach up to 37 000MW at any one time with lights on for longer periods, people using heaters and cooking more. Eskom did not do maintenance in winter for this reason.
Etzinger said load shedding was done according to a predetermined schedule published on its website, www.eskom.co.za.
”The idea is, unfortunately, that everybody gets their turn. We do it on a rotational basis.”
He said the national grid was divided into six regions.
”We apportion the amount of load shedding required to each of these regions.
”We do our best to limit load-shedding to two-and-a-half hours.”
He said the load-shedding portion of this was two hours, but an extra half hour was added to enable electricity to be restored. Sometimes this took a while, as equipment had to warm up again.
He said anyone unsure whether they were subject to load shedding or a power cut could contact Eskom’s help-line on 08600-Eskom (08600 37566).
There was not a traffic light working between Forest Town and Greenside, and they were also out across the West Rand, said a motorist resigned to the recent frequency of power-related traffic disruptions.
However, he pointed out that traffic chaos had been alleviated by the absence of those Johannesburgers already out of the city on holiday.
”We appeal to all consumers to use electricity sparingly and use electrical equipment such as air-conditioning, geysers and swimming pool pumps as efficiently as possible in order to reduce the demand of electricity and to assist in minimising load shedding,” Eskom asked on its website. — Sapa