Eskom CEO Brian Dames says power consumers need to save 10% or 3,000 Megawatts (MW) from the 2007 base line so that the electricity parastatal can carry out necessary maintenance on middle-aged power stations.
Dames was speaking at a briefing at Megawatt Park on Monday.
Power station managers regularly asked Dames when they could take some of their units offline, as if they did not carry out maintenance, there was a risk of catastrophic failure due to the system being overly stressed.
As a steam pipe network replacement took around 120 days, planning maintenance was a critical question, but if there were demand savings, then this created space for the necessary savings, Dames added.
Eskom said on Friday in its twice-weekly capacity update service that unplanned outages were 5,521 MW on January 26 compared with 5,497 MW on January 23, some 5,373 MW on January 19, while they stood at 4,274 MW on January 16 and 3,678 MW on January 13.
The electricity generating capacity available to meet peak demand on January 26 was 33,189 MW, while demand was expected to be 31,106 MW. Current planned maintenance stood at 4,286 MW.
Eskom has moved to twice a week updates instead of the previous quarterly updates in line with its commitment to regular and transparent communication on the power system, which was expected to be constrained for at least the next two years.
On January 17 peak demand of 31,278 MW was met by available capacity of 32,954 MW - a margin of 1,676 MW (5%) or around three modern 600 MW coal-fired generators.
On January 9 peak demand of 30,282 MW was met by available capacity of 30,742 MW or a margin of only 460 MW (less than one generating unit at a modern coal generating plant) or only 1.5%. The internationally accepted safe margin was set at 15%.
The reason for this low margin in SA was that Eskom carried out planned maintenance on its power stations during the seasonally low demand summer months, so that power stations were ready to handle the peak winter demand months of June and July, when service delivery protests also peaked.
On January 12, capacity taken offline for planned maintenance was 4,461 MW or around nine generating units, but unplanned outages were 3,678 MW or around seven generating units. Last year in February, a 600 MW generating unit at Duvha failed during tests as it was being returned to service, while in January 2003 a similar event took place.
For this year and next year Eskom did not possess the spare capacity to be able to have a large generating unit fail, as the first unit of the new Medupi power station was expected to only come on line in 2013. - I-Net Bridge