Johannesburg - Eskom CEO Brian Dames on Tuesday urged South Africans to save electricity during summer, adding that the commercial sector can make the biggest difference.
He said the system outlook for summer remained tight.
Unlike winter, where the peak period was between 17:00 to 21:00, the demand profile for summer was "flatter", with an increased demand profile throughout the day.
This was primarily a result of the use of geysers and air-conditioners.
Dames said that if there was a constraint, the system would be constrained for the entire day.
"Unlike winter, where residential customers had the greatest impact, during the summer it is primarily the commercial sector that can make the biggest difference," he said.
"The challenge is to ensure that there is sufficient generation capacity throughout the day. This summer, please remember that less is more. The less electricity you use, the more electricity will be available to go around," said Dames.
The utility said it met its winter electricity demand.
"It is an exceptional achievement to meet winter demand and do more maintenance than before."
Maintenance at five of the nine power station units had been completed and three were in the process of being serviced. The last one would be completed towards the end of the month.
Dames said Eskom had adopted a five-year plan which was aimed at ensuring a sustainable generation fleet.
"One that will not only generate power more reliably now, but will continue to do so over the useful lives of our power stations," he said.
"The new plan will see us target 10% of our generation capacity on average through the year to do fixed, planned, design-based maintenance, to address safety, reliability and emissions issues at our power stations."