Sustainable availability?

At the peak of South Africa’s load-shedding crisis, much emphasis was given to adding new capacity, especially private capacity, as well as to increasing energy efficiency. These remain laudable objectives. However, in the absence of demand growth, the most important issue then, and now, lies in ensuring that the existing fleet of coal-fired power stations delivers the power for which it is designed. To be sure, if Eskom had been able to operate anywhere close to its old 90-7-3 operating model, South Africa would never have descended into an electricity crisis. Under that framework, the power stations would be available 90% of the time, with planned outages of 7% and little room (3%) for unplanned breakdowns. Some believe the model may have been unrealistic and that, in the context of an aging fleet, sustaining an energy availability factor (EAF) of 90% helped precipitate the high level of breakdowns and the eventual slump in the EAF below 70%.