"Despite some units having returned to service last night [Friday], stage three load shedding will be implemented from 09:00 today [Saturday] to accommodate the shortage of capacity and to replenish emergency reserves, until 05:00 on Monday," Eskom said in a statement.
Diesel reserves for open cycle gas turbines and water reserves for the hydro-pumped storage schemes were used extensively on Friday and overnight to supplement the shortage of capacity, and were not at adequate levels to sustain the capacity shortage for Saturday.
"Unplanned outages, or breakdowns", were at 10,612 MW as at 6am on Saturday, while planned maintenance was at 6574 MW. As the system was vulnerable, any additional changes on the system performance may require a shift in stage at short notice.
"We remind customers that load shedding is a highly controlled process implemented by the system operator to ensure the security of the power system and to prevent a national blackout. Eskom reminds South Africans that there is a possibility of increased load shedding over the next 18 months as we are conducting critical maintenance to restore the ageing plant to good health."
Eskom also appealed to customers to continue to use electricity sparingly and to assist in reducing demand.
African News Agency (ANA)