Cape Town - Eskom has repeated its urgent call on electricity users to help it "beat the peak" this winter by switching off non-essential appliances between 17:00 and 21:00 each day.
Briefing members of Parliament's public enterprises portfolio committee on Tuesday, Eskom CEO Brian Dames said while Eskom was confident it could supply power "most of the day", the utility's primary concern was early evenings, when there was a significant spike in demand.
"We believe that it's more than do-able, with the support of customers, to reduce that demand over that peak period. We think that [a drop in demand] of more than 2000MW will be more than enough to ensure the security of supply within [that period]."
Dames said Eskom intended performing essential maintenance on nine power generation units between April and August.
This was unavoidable for the long-term sustainability of its power plants. He said if four million households switched off their hot-water geysers between 17:00 and 21:00 each day, this would yield the electricity saving needed.
"The message for this winter is it's going to be different to other winters because we have to do this maintenance that we can't postpone any longer. Our intention is to keep the lights on. We think it is possible, but we can't do it alone -- everybody must work with us," Dames said.
"If everybody works with us, particularly over that peak period, we can make sure we keep the lights on and do the maintenance we need to do."
Referring to the maintenance needed on the nine generation units, he said this could take up to six months. Some of it could take as long as 180 days, while a "short" maintenance period would be 40 days.
Among the questions put to Dames at Tuesday's briefing was whether rumours were true that he planned to quit his post.
African National Congress MP Aubrey Mokoena asked him: "Mr Dames, there was rumour that you, as CEO, were going to leave Eskom. Can you categorically dispel or confirm [this rumour]?"
Dames replied he was "fully committed" to the job.
"It's very important that Eskom, with its 40 000 people and 40 000 contractors, is stable; that it has leadership in place that knows what it's doing and what it's working towards," he said.
"I'm fully committed to what I have to do and to lead Eskom, if that is what I'm asked to do. I've got a team that is in place and they've been together for some time and that is important."
Eskom played an important role in South Africa and "my commitment is to make sure we do that", he said.
In a statement on Monday, Eskom said peak demand this winter was forecast at 36.8 gigawatt (GW), but this was the average for an hour. The "peak within the peak" could go as high as 37GW to 38GW.
One gigawatt is equal to 1000 megawatts (MW).
Going into winter, demand could spike by more than 3000MW during the evening peak -- equivalent to the output of five generating units at a large power station.
Responding to a question at Tuesday's briefing about switching household geysers off between 17:00 and 21:00, Dames said this would not cause damage or result in a higher electricity bill.
"It is better to switch a geyser off, then switch it on when needed... it does not damage the geyser, and you do not use more power," he said.