As a result of the loss of additional generation, delays in the return to service of units that are on planned maintenance and limited diesel supply, it has become necessary to implement stage 2 rotational load shedding from 09:00 until 23:00 in order to protect the power system from a total collapse.

In the System Status Briefing of September 4, Eskom warned that in order to avoid load shedding, unplanned breakdowns needed to be contained at below 9 500MW. In the event generator breakdowns are experienced beyond 10 500MW there will be high usage of emergency resources (diesel and pumped storage generators), which may lead to load shedding if the supply constraints are sustained for a long duration.

The severe supply constraint being experienced has come about due to high levels of unplanned breakdowns that have exceeded the 10 500MW limit. The supply constraint is caused by, among others, five generating units that are unavailable due to boiler tube leaks. In addition, a conveyor belt supplying Medupi Power Station with coal failed on October 12 resulting in low volumes of coal being supplied to the power station thus limiting the generating capability to approximately half the station output.

Due to the shortage of generating capacity from coal-fired generation, the pumped storage and OCGT generators have been used extensively since Saturday, October 12 which has led to a decline in the dam levels and diesel tank levels.

“We unreservedly apologise to South Africans for the negative impact this may have on them and want to assure the nation that we continue to work tirelessly to ensure security of energy supply,” Juanita Vogel, stakeholder management and communication practitioner for Eskom’s corporate affairs division said.

To assist in this effort, Eskom has appealed to customers to continue to use electricity sparingly throughout the day applying the following rules:

• Set air-conditioners’ average temperature at 23ºC
• Switch of your geysers over peak periods
• Use the cold water tap rather than using the geyser every time
• Set your swimming pool pump cycle to run twice a day, three hours at a time for optimal energy use.
• At the end of the day, turn off computers, copiers, printers and fax machines at the switch. Avoid standby or sleep mode.

Customers are advised to check their load shedding schedules on the Eskom or municipal website.