Eskom’s breakdown and planned maintenance changes — Charts explain big load-shedding break

Eskom conducted more planned maintenance on its power stations in 2024 than in the previous four years, while unplanned breakdowns have also started to improve.

However, the biggest reason for lower load-shedding than in the past few weeks is a drop in demand due to increased solar-powered self-generation and less economic activity.

MyBroadband compared the key metrics Eskom uses to assess the performance of its generating fleet — energy availability factor (EAF), unplanned capability loss factor (UCLF), and planned capability loss factor (PCLF).

The UCLF — also known as the unplanned outage factor — shows what portion of Eskom’s total generating capacity is offline due to unscheduled breakdowns.

PCLF — or planned outage factor — refers to what portion of the fleet has been taken offline as part of controlled and scheduled maintenance work.

Eskom also tracks the other capability loss factor (OCLF), which it describes as losses in capacity that are due to factors out of its control.

An example of this is management problems that can cause insufficient coal deliveries.

Finally, the EAF is what remains — the portion of Eskom’s generating fleet capacity that is available to provide power at a given time.

When counted together, these factors should make up 100% of the total installed capacity of Eskom’s fleet.

Over the past few months, electricity minister Kgosientsho Ramokgopa has repeatedly stated that the utility will ramp up planned maintenance (PCLF).

He explained that this would lead to “short-term pain” with reduced generation availability for some time. However, the goal is to enable long-term improvements in the system.

From Eskom’s data, we found that the utility’s planned maintenance for the year-to-date was indeed substantially higher than in the previous four years.

As of week 15 of 2024, Eskom’s PCLF stood at 15.33%, up from 10.90% in 2023. This was also higher than the five-year peak PCLF of 11.24% in 2020.

Unplanned breakdowns had also improved, with the UCLF at 30.47% compared to 33.08% in 2023.

However, the figure was substantially worse than the 20.88% UCLF of 2020.

We also confirmed that the figures improved compared to the same weeks in the previous years – at least going as far back as 2021.

However, because Eskom only started publishing its system status outlook in 2021, the year-to-date numbers for 2020 were not available.

The chart below summarises Eskom’s unplanned outage, planned outage, other outage, and energy availability factors in week 15 of 2024, compared to 2020, 2021, 2022, and 2023.

Click to enlarge

From the figures above, it appears Ramokgopa’s statements largely held true.

However, EAF is still at a worse level than in previous years, including the dismal 2023, which means that Eskom’s situation has not truly improved.

Without knowing how much of the capacity provided by units under Eskom’s planned maintenance schedule could quickly be brought online in the event of several unexpected breakdowns, it is unclear if the utility is truly better geared for avoiding load-shedding.

According to energy experts like Chris Yelland, the main reason Eskom has not needed to implement load-shedding for several weeks is a reduction in energy demand because of radical uptake in rooftop solar and decreased business activity.

Eskom itself has started including estimations for the contribution of rooftop solar PV in its system status outlooks. As of week 15 of 2024, it calculated this stood just shy of 5,440MW, about 1,100MW more than at the same time last year.

Eskom’s latest data also shows that its contracted and actual energy demands have dropped substantially compared to previous years.

By 14 April 2024, Eskom had sent out 56,263 gigawatt-hours (GWh) of electricity, about 5% lower than in 2023, which was already one of Eskom’s worst years in recent history in terms of energy demand. Compared with 2020’s 59,781GWh, actual demand was roughly 5.9% lower.

The graph below shows how Eskom’s annual residual energy demand and contracted demands declined in 2024 compared to the previous four years.

RSA contracted demand is the total official day-ahead hourly forecast, excluding the expected generation from renewables.

Residual energy demand refers to the actual metered hourly sent-out generation and imports from dispatchable resources, including demand reductions like load-shedding. All numbers on the chart are in GWh.

Click to enlarge

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Eskom’s breakdown and planned maintenance changes — Charts explain big load-shedding break