Picture File: A general view of Matla Power Station on 9 March 2021 in Secunda, South Africa. Picture: Gallo Images/Lefty Shivambu
This was not the plan. In January, Eskom chair Mpho Makwana warned South Africans that Stage 2 and Stage 3 load shedding would become a near-permanent fixture over the next two years. So far this year, it’s been more a case of Stage 3 and Stage 4 … with sprinklings of Stage 5 and 6 thrown in for good measure.
The only reprieves have come on Sundays (Stage 2, sometimes Stage 1) where demand is structurally about 2 000 megawatts (MW) less than a typical weekday.
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Recently, Eskom confirmed to Bloomberg that it will not meet its own target of increasing generation from its six priority power stations by 1 862MW by the end of this month. This is equal to nearly two stages of load shedding.
At risk is the 6 274MW of total capacity that it wants to recover from Tutuka, Kendal, Duvha, Majuba and Matla over the next two years. This includes the return of Medupi Unit 4 (which exploded in August 2021) and the completion of Kusile units 5 and 6.
A recovery of this generation capacity would get its energy availability factor (EAF), a measure of available output, to 59% by the end of its financial year (30 March 2023). So far (since 1 April 2022), its average EAF is 56.6%.
In recent weeks, it has not been higher than 54%. The last time it was any higher than the average for this fiscal year was the first week of November.
This includes the contribution from Koeberg (currently 50%), imports (where damaged towers have reduced the amount of power available from Cahora Bassa in recent weeks), pumped storage schemes and open cycle gas turbines (OCGTs).
On Friday, breakdowns across its generating units (including those imports) finally dropped below the 17 000MW level they had been at practically all month (16 469MW).
In March thus far, its coal fleet has not been able to generate more than 20 000MW (it reached 19 848MW on Friday 3 March).
The return to service of a number of units that had been out of service for maintenance has ensured a reprieve from load shedding this weekend. However, any planned maintenance would’ve been scheduled months ago.
Breakdowns are looking significantly better (at 15 500MW) and keeping this number under 16 000MW would go some distance to limiting the severity of load shedding in winter months.
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The problem staring Eskom in the face is that peak demand in winter will be at least 3 000MW higher than the ±30 000MW it is currently generating.
What is curious is the fact that Eskom’s demand forecast has been adjusted downwards in those June and July weeks.
Quite why Eskom sees peak demand being as much as 2 000MW lower than it thought is unclear. It is worth noting that its demand forecasts are generally fairly accurate (within a 1% margin, mostly around 0.5%).
Based on these revised forecasts, the gap is smaller than it was thought to have been but is still somewhere between 3 500MW and 4 000MW from current peak demand levels.
By the end of May, Eskom has to plug this additional shortfall to avoid implementing significantly worse load shedding than it currently is.
The simplistic calculation, which some news outlets have done, is to add three stages of load shedding to current levels. The reality is far more complex.
First, imports from Mozambique ought to be running at full capacity (currently 400MW lower than normal). It will also have money available to burn diesel at its OCGTs (much of this would’ve been budgeted for in the new fiscal, despite Nersa attempting to limit the usage of these peaking plants).
Still, the severity of load shedding this winter will depend almost entirely on the performance of Eskom’s coal power stations.
Planned maintenance will drop to 2 000MW (some weeks below 1 500MW) during winter from the middle of May. This has been hovering at around 4 500MW to 5 000MW in recent months. It’s trying to get ahead of its maintenance backlog to get the fleet in the best possible shape for winter.
Just by cutting maintenance to the bone – as it does each winter – Eskom will theoretically have at least 2 000MW of generating capacity than it does at present.
Keeping breakdowns under 16 000MW will make a big difference. This is not far off current levels, with the added plus that partial load losses from coal plants tend to reduce in cooler winter months. Anything under this (it uses a “likely risk scenario” of 16 700MW of unplanned outages) will be a bonus.
There have been improvements. On Thursday, it announced that six of its coal power stations had achieved EAF of 70% over the past week. This, it says, was last achieved in May 2022.
Lethabo, Matimba and Medupi are already among Eskom’s top-performing power stations, while two of the other three – Duvha and Matla – are on its list of worst-performing stations where it is targeting turnarounds.
The sixth, Camden, has been somewhere in between. It says the six stations “have been on a sustained upward trend as a result of a reduction of plant breakdowns and the return to service of a number of units that were on unplanned breakdowns”.
But this remains a stark turnaround from the first two months of the year.
Using Eskom data, independent energy analyst Clyde Mallinson calculates that the capacity factor (usage, not availability) of the coal fleet was below 50% in January and February.
If this dips to 45% – it was at or below this mark for easily half of the first two months of the year – Stage 8 load shedding for the peaks in June is almost certain.
Additionally, Koeberg Unit 1 should return from its steam generator replacement outage in June. With 900MW of stable, dependable output, there’s much riding on the successful execution of this project.
This chunk of generation capacity is included in that theoretical 2 000MW-plus gain from much lower planned maintenance. However, work outages at nuclear plants seldom run on time.
This article originally appeared on Moneyweb and was republished with permission.
Read the original article here.
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