Carol Paton | 20 May 2013 | BDLive
ESKOM "came as close to the edge as you can get" last Monday evening when the available power supply exceeded demand by a margin of only 0.17%, according to the company’s own routine system status bulletin.
The recommended reserve margin for a power system is between 10% and 15%.
While Eskom spokeswoman Hilary Joffe on Sunday downplayed the event, saying it was caused by units that had been taken down for weekend maintenance not being brought back in time, energy analyst Chris Yelland said he had been "flabbergasted". "That is as close to the edge as you can get. The bottom line is that it is damaging. It is running this country at high risk," said Mr Yelland.
Ms Joffe said that except for Monday, the system had been operating with a bigger reserve margin in recent weeks than during March and last month. During this period the system was constrained due to unplanned outages that included one unit of Koeberg and far-reduced supply from Cahora Bassa. The Koeberg problem has now been rectified.
"Monday is very often a tight day as over the weekend units are taken out for planned maintenance. Sometimes, due to unexpected problems, the units might not be back in time. That is what happened on Monday," she said.
Eskom warned last month that South Africa would face a tight system over winter. In a special briefing along with Public Enterprises Minister Malusi Gigaba, Eskom CE Brian Dames said going into winter the company faced both increased demand and routine maintenance that could not be deferred any longer. The growth in unplanned outages was a sign that maintenance had been neglected, he said.
"The country must understand that for the last five years we have managed to keep the lights on. We did this by operating our power system much harder. Now it requires substantial maintenance to maintain performance," he said at the time.