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By Moneyweb

Moneyweb: Journalists

Eskom’s coal power stations face alarming decline, report reveals

Kendal has an effective output of 3,800MW, Tutuka 3,500MW and Duvha almost 2,900MW.

New data from the 600-page report produced by German engineers at the behest of National Treasury shows just how shocking the decline in performance of some of Eskom’s coal-fired power stations has been. On a percentage basis, the energy availability factor (EAF), or a measure of available capacity, has roughly halved since 2010. 

The three power stations, Tutuka, Duvha and Kendal, could boost output by about 3,000MW – equivalent to three stages of load shedding – if they performed in line with the best-performing large stations in its coal fleet. Together, these three stations are capable of generating 10,000MW.

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Kendal has an effective output of 3,800MW, Tutuka 3,500MW and Duvha almost 2,900MW.

Memorably, an explosion at Unit 4 of the latter ripped through the power station and rendered 600MW of capacity useless. That was in 2011.

Many years later, Eskom elected to use the proceeds from insurance for operations instead of replacing the turbine, rendering this capacity no longer available to the grid. 

Still, the decline in performance at these three stations has been astonishing. 

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Tutuka, the single worst-performing Eskom power station, generates just a quarter of its nameplate capacity (on average). Duvha and Kendal each produce less than half of what they are supposed to. 

The shocking performance of Eskom’s three worst power stations
Source: VGBe Energy report

Crucially, the next three worst-performing power stations aren’t doing much better.

Only one, Kusile, has improved significantly since the figures in the VGBe Energy report. Kusile lost three units following the collapse of its flue gas duct (chimney) in 2022. It took about a year to get these back online with temporary structures. 


Tutuka is a hopelessly broken power station. At the time of the report (April last year), VGBe says that “due to insufficient maintenance the plant suffers from a high number of losses”.

“In April 2023, approximately 13% (461 MWe) of the installed net capacity of 3 510 MWe was not available due to PLL [partial load losses]. Another 67% (2 340 MWe) were unavailable due to full load losses (FLL) during the visit.”

ALSO READ: Unit 1 at Koeberg Power Station back in operation

Partial load losses across the three worst-performing power stations plus Majuba total an outrageous 3,000MW. This is the crux of the matter. Across the six worst-performing stations when it comes to partial load losses, the total is 4,000MW – equivalent to four stages of load shedding. 


Almost absurdly, the average PLLs at Kendal equated to nearly a third of capacity in the last financial year. 

The VGBe report is clear: “Kendal has been reliable in the past, but over the last four years it has shown signs of its age and of a lack of adequate maintenance. One of the best operating plants in the system in 2018, it reached 46% EAF in 2022. Deferred general overhauls have contributed substantially to its recent unreliable performance.

ALSO READ: Kusile power station units return, good news for load shedding?

“After 30 years in operation and considering that it is expected to operate for another 20 years, it is due for a mid-life rehabilitation.”

One can see that decisions made in the second half of the 2010s are now coming back to haunt Eskom. One can achieve a very decent EAF from a unit without maintenance, but at some point, that will catch up to you. Those chickens are coming home to roost.


Of Duvha, the report says it “is more than 40 years old”.

“Due to insufficient maintenance, the plant suffers from a high load loss. In March 2023, almost 30 percent (780 MW) of the installed capacity of 2 875 MW (net) was not available due to PLL. One of the main PLL contributors is the draught plant. Even if operated at maximum load, the ID fan [induced draft] capacity is not high enough to guarantee appropriate pressure in the furnace. This can be mitigated to a large extent by tightening the flue gas ducts and air heaters.

“We strongly recommend also inspecting and re-pairing all other potential sources of air ingress at the boiler.”


The performance of Majuba – not one of the three worst-performing plants – is astonishing. The report says, matter-of-factly, that “the age of Majuba power plant is in the range of 22 to 27 years, but due to insufficient maintenance the plant already suffers from a high amount of power losses”.

“In April 2023 almost 40% (1 506 MWe) of the installed net capacity of 3 807 MWe was not available due to PLL.”

ALSO READ: Kusile unit return ‘a temporary fix’, warns energy expert

The 1,500MW is basically 1.5 stages of load shedding! 

Load losses

On average, eight of Eskom’s 15 coal-fired power stations experience partial load losses of more than 400MW. 

Fixation on EAF ‘must stop’ immediately

The report says the “fixation on the EAF is a dead end and leads to poorer plant performance”:

  • Over the last months and years, outage and maintenance activities have been deferred to lift – or at least maintain – the EAF;
  • The priority of the Eskom coal fleet operation has been to quickly fix the actual bottlenecks in generation capacities rather than to restore the plants to “as new conditions” after an outage;
  • The plants have been forced to continue operating at the expense of their technical condition. The consequences are reflected in the high number of incidents, trips and partial load losses; 
  • This cycle has now gained so much momentum that it could lead to the collapse of plants or to further capacity losses. It must be stopped immediately by executing proper maintenance and outage work – even if this means a higher level of load shedding for a limited period of time.

Critically, it says “up to 6 000MW in partial load losses (PLL) could be reactivated by fixing the plants’ defects and applying prudent operation and maintenance practice”.

With elevated levels of planned maintenance in recent months, this might just be what Eskom is busy with … let’s see. 

This article was republished from Moneyweb. Read the original here

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