Load shedding all but guaranteed this summer, says Eskom

Eskom’s outlook for the summer months of September to March, based on unplanned outages of 13 000MW across its generation fleet, is for 22 days of Stage 1 load shedding.

This reaches a peak in February, with load shedding likely on 13 days – practically half the month.

The power utility was briefing parliament’s joint portfolio committees on Public Enterprises and Mineral Resources and Energy on Wednesday.

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Eskom says “the plan requires open cycle gas turbine [OCGT] usage over weekdays and low diesel usage on some weekends”.

It highlights that the “failure” of Medupi unit four, which exploded in 2021, has “increased the dependency on diesel generation to manage the power system”.

Eskom, in its base case for summer, estimates a total diesel bill of R9 billion.

The less-sunny scenario

In a second scenario, predicated on unplanned outages totalling 14 500MW, Stage 2 load shedding will be needed for five of the six months, with Stage 3 necessary in February.

Load shedding would be needed on between 10 and 20 days per month between now and March, with an average of 17 days.

In this case, the plan requires diesel usage of as much as R5.5 billion per month which is simply not possible due to the physical limitations of getting fuel to the peaking plants.

(In a more extreme scenario, where 16 000MW is unavailable, load shedding between Stage 3 and Stage 4 would be needed practically every day for the next six months, even in December when demand is at its lowest).

OCGT overreliance

Since April, Eskom has operated its OCGTs at a load factor of 16.4% to keep the lights on. The National Energy Regulator of South Africa (Nersa) has however only approved a load factor for the diesel turbines of 3% for this financial year.

The load factor of OCGTs operated by independent power producers has been 9.9% since April.

It is worth noting that Eskom’s outlook for winter wasn’t even close to the mark.

To be fair, near-constant load shedding in late June and July (peaking at Stage 6) was due to illegal industrial action at many of its power stations. It took the utility weeks to recover from this.

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Readers will recall that in May, Eskom published its ‘base case’ for winter which saw no load shedding and only R1 billion spent on diesel for its OCGTs until August.

The worst case scenario – predicated on 15 000MW of generation being offline due to unplanned outages across winter – saw load shedding required on 104 days until August 31. In this scenario, diesel costs were expected to total more than R7 billion.

Eskom says that for 41% of the time during winter, it was operating at levels forecast under this worst-case scenario.

Worse, it says that for “42.5% of the time we operated above the maximum assumption for the winter plan”. This means that breakdowns were above its worst-case scenario. (For nearly 12% of the time, more than 16 500MW of generation capacity was offline for reasons other than maintenance).

Therefore, for more than 80% of the time during winter, Eskom had unplanned outages (breakdowns and partial load losses) above 13 500MW. The average level of these outages over evening peaks during winter was 14 864MW during the winter half of the year.

It says increasing the base case of unavailability to the 13 000MW level is “based on the performance over the past year”.

Eskom also says the steam generator replacement at Koeberg’s unit one “will significantly increase the risk of load shedding for 240 days”.

Predictable unpredictability

The generation fleet does not operate predictably or linearly; rather, there are ‘bursts’ of load shedding. Breakdowns necessitate the need to run marginal plant even harder as well as exhaust emergency reserves.

This creates a situation where those plants become even more unpredictable and more prone to breakdowns.

In this situation, repairs could be rushed to get plants back online as quickly as possible, meaning these units are more likely to then break down again.

Aside from the load shedding it implemented to get through the evening peak through much of winter, it typically takes the utility a number of days to recover from load shedding.

It says there is a ±2000MW variance in unplanned outages, often in one week: “In practical terms, it means we operate in the range of having 2 000MW of reserve to needing Stage 2 load shedding to create sufficient reserves.”

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Bringing in extra power

In the next 12 months, Eskom says it will procure 2 360MW of generation capacity. Most of this will be from emergency power procurement and additional imports from neighbouring countries.

A further unit at Kusile will come online within the next year. It also expects 3 200MW of generation to be restored from improving the performance of its existing fleet.

Within 24 months, it expects to add more than 15 000MW to the grid.

A significant chunk of this – around half – will likely be towards the end of this two-year period (possibly even longer). By this point, it is expected that at least some of the projects in renewable bid windows 5 and 6 as well as the risk mitigation independent power producer procurement programme will come online.

All the successful bidders in bid Window 5 are yet to reach financial close.

This article originally appeared on Moneyweb and was republished with permission.
Read the original article here.