By Roger Lilley, Energize

As winter nears and temperatures drop, everyone’s on tenterhooks regarding the ever-increasing frequency and depth of load shedding. In the month of May so far, the average load was 29 600 MW, and the average dispatchable generation capacity was 27 500 MW. That includes all of Eskom’s generators as well as the power it receives from independent power producers. Even without any reserve – and we should have about 5000 MW generation capacity in reserve – we are already 2000 MW short.

At its latest briefing, the Winter Outlook Briefing, Eskom acknowledged that intensified load shedding was having a devastating impact on South Africa’s economy. This, it says, is despite several positive developments the power utility has taken to address its many challenges.

In summary, the utility reports:

• The winter outlook indicates an increased risk of supply shortfall against expected demand, with its worst-case scenario indicating that load shedding could intensify to Stage 8, should its interventions prove unsuccessful.
• The increase in load shedding levels does not mean there is a greater risk of a national blackout, Eskom insists. Rather, load shedding is one of the processes the utility uses to prevent such an occurrence by managing the demand for electricity at any given time.

Eskom says that efforts to reduce and ultimately end load shedding require all electricity stakeholders to work together to drive interventions both on the supply side (improving available generation) and the demand side (reducing peak demand). It remains committed to increasing the amount of available generation, with a specific focus over the winter period, by:

• Reducing its unplanned losses in the generation fleet
• Managing planned maintenance to the minimum level of maintenance required over the winter months
• Increasing the use of its diesel-fired open cycle gas turbines (OCGT)

The utility adds that it is driving the Generation Operational Recovery Programme (GORP) (see Figure 1) with the support of its Board to sustainably recover the performance of the plants over the next 24 months.

To ensure the success of GORP, the organisation is focusing on leadership stability, skills interventions, and partnering with industry and other Government departments.

While the power utility admits that much more needs to be done to reduce the level of electricity demand specifically during the peak, it says that the public could offer greater support in its efforts to mitigate the impact of the energy crisis, especially over the winter period, by reducing demand wherever possible.

The latest report also shows a worsening of the Energy Availability Factor (EAF). The utility achieved an EAF of 52% against a target of 60%.

In its State of the System briefing in November 2022, Eskom reported that it had achieved an EAF of 58% against a target of 65%. This means that the EAF has fallen by 6 percentage points from 58% to 52% in six months.

Generation capacity loss occurs mostly through breakdowns, the utility says, which currently removes over five times the amount of power than scheduled maintenance does.

According to the figures given on 24 May, 16 486 MW of generating capacity was lost through breakdowns, while 3817 MW was lost due to planned maintenance.

In the past 24 hours, a generating unit at Duvha Power Station broke down, and the delay in returning units to service at Arnot, Camden, Kendal, Tutuka, and two generating units at Hendrina power stations continue to add to the current capacity constraints. These generating units will be returned to service as soon as possible, Eskom says.

Other technical problems plaguing the utility are the loss of power due to the flue gas duct incident at Kusile and delays to the return to service of Koeberg Unit 1. Together, these two power stations have removed over 3000 MW of generating capacity.

The power utility warns that should the shortfall in generation vs demand (known as load losses) fall to 18 000 MW load shedding beyond Stage 6 would need to be applied to balance generation and demand.

However, the utility assures the public that efforts are underway to return the various power station units from outages, reduce partial load losses and maintain planned maintenance between 1300 - 3000 MW over the winter period. Eskom claims that it will intensify demand-side management and increase the use of its diesel-powered generators to reduce the supply deficit as much as it can.