Electricity producer Eskom warned on Tuesday it would take some time to arrest the current high levels of unplanned outages, revealing that 32 of its 87 coal-fired generating units required “major surgery”, while four were in a “critical condition”.

However, addressing the Portfolio Committee on Energy in Cape Town, interim CEO Collin Matjila stressed that it remained confident that inroads were being made to deal with the problem.

In 2013/14, the group’s unplanned capacity loss factor, or UCLF, rose to around 11%, while its energy availability factor (EAF) fell to 75.1%. Eskom was forecasting plant availably of 75.5% for the remainder of the 2014/15 financial year.

A five-point recovery plan had been introduced to improve the performance of the coal-fired fleet, with Eskom having reaffirmed its objective of returning to an ‘80-10-10’ operating model, which implied 80% plant availability, 10% planned outages and 10% unplanned events across a period of a year.

Eskom also cautioned that an additional 7 400 MW of capacity was required to provide it with the cushion it needed to enable it to deal with its maintenance requirement.

Planned outages were set to increase to 10% of capacity as Eskom entered its high-maintenance summer period and the State-owned utility was forecasting that the system would “remain tight” throughout summer – the season during which the utility had historically resorted to rotational load shedding.

The degree of tightness would depend on the UCLF, owing to the limit prospects for new capacity. Although Medupi’s first 794 MW unit was scheduled to be synchronised to the grid on December 24, Unit 6 was expected to be operating at stable levels only by winter 2015.

In addition, should Eskom limit its use of the expensive open-cycle gas-turbines (OCGTs) to levels approved in the corporate budget, it warns of an inability to meet the demand throughout the remainder of the financial year.

Eskom spent a whopping R10.5-billion on diesel fuel in 2013/14, which was R8.1-billion above the R2.5-billion set aside by the regulator in its revenue determination for the period. Total OCGT production was 3 621 GWh, which as also significantly ahead of a budget of 1 284 GWh, translating to a load factor of over 19.3%.

“If target EAF is met then there is low risk of load shedding, but this cannot be ruled out due to daily variability,” Eskom told lawmakers, adding that if load was shed during summer it was likely to be from 06:00 until 22:00 and as per published schedules.

To avoid or limit planned or scheduled load reductions could require additional use of the OCGT plants in the Western Cape.

Also addressing the committee, Public Enterprises Minister Lynne Brown stressed that it would be some time before South Africa’s energy shortages were a thing of the past.

“Until then and even after that, we should all be aware of our shared responsibility in ensuring not only sustainable energy supply but also sustainable energy consumption,” she said, while also offering the assurance that the corner had been turned at Medupi.

Describing Medupi as key to Eskom’s bigger capacity expansion programme designed to secure electricity supply, she said the project by itself would grow South Africa’s gross domestic product by about 0.35% a year.

Group executive for the capital division Dan Marokane indicated that additional resources had been mobilised to Unit 6 by both the boiler contractor and the control and instrumentation contractor to mitigate any further delays.

Following labour disruptions in July, the workforce had returned and additional shifts had been introduced “24 hours a day, seven days a week to accelerate progress on site”.