Only three of Eskom’s coal plants are consistently producing over 2 000MW

So far this year, only three of Eskom’s coal power stations are consistently generating more than 2 000 megawatts (MW) of power, on average

It has a total of 14 coal power stations, of which only three have total capacity below 2 000MW. Of the remaining 11, seven have generating capacity of more than 3 500MW*. These are big power plants.

This was revealed by executives from the utility in a presentation to the Mineral Resources and Energy Portfolio Committee in parliament on Friday.

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For sure, the sample period for this is relatively short – just three weeks (to 22 January) – but the performance of Eskom’s generating fleet remains horrendously below par.

In the first three weeks of the year, the energy availability factor (EAF), a measure of available generating capacity, for its coal units was 48%.

Overall, EAF was 53.3% for the bulk of January. This is laughably below its stated 65% target for 2023/24.

What affects EAF

EAF is impacted by planned maintenance and breakdowns. Eskom has kept the planned outage factor elevated at 13.3% of the fleet for this period, a touch higher than the 12.2% achieved in the comparable period in 2022.

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Breakdowns include full load losses, outage slips, boiler tube leaks, trips, and partial load losses. It is the last of these that has been the major contributor to unplanned losses in recent years.

Until October, it had contributed to losses of nearly 13% of total capacity. This was followed by full load losses (nearly 10%). Of that 10%, more than half were defined as “major events”, meaning large units (±600MW) being offline for nearly a month. At that point, total unplanned losses equalled 32.2% of installed capacity.

Top three

It is no surprise that the three that are producing more than 2 000MW consistently are among the best-performing stations across Eskom’s fleet.

Lethabo, whose manager Thomas Conradie is currently acting group head of generation, produced (on average) 2 759MW for the first three weeks of the year (from total capacity of 3 558MW). This equates to an EAF of 77.5%.

Matimba, which has also been a ‘dependable’ station historically, achieved a very similar EAF figure of 74.3%, with 2 742MW being produced out of 3 690MW, on average.

Medupi, where performance has steadily improved over the past year, achieved average output of 2 075MW (from 3 600MW), meaning an EAF of 57.7%. Unit 4 remains offline since it was blown to pieces just more than a month after the ‘official’ completion of the entire power station in 2021. This unit will return by August next year.

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