New data in a 600-page report prepared by German engineers at the request of the National Treasury shows just how shocking the decline in performance of some of Eskom's coal-fired power plants is. On a percentage basis, the Energy Availability Factor (EAF), a measure of available capacity, has fallen by roughly half since 2010.
Tutuka, Duba and Kendal power stations could increase output by around 3,000 MW if they performed as well as the best-performing large coal-fired plants, which would be Corresponds to three stages of blocking. Together, these three stations can generate 10,000MW.
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Read: Eskom needs practical help – report
KendaThe effective output is 3,800MW, Tutuka is 3,500MW and Duvha is almost 2,900MW.
Fresh in the memory is the latter's explosion at Unit 4, which destroyed the power plant and rendered 600MW of capacity unusable. That was in 2011.
Many years later, rather than replacing the turbines, Eskom chose to use insurance proceeds for operations, leaving this capacity unavailable to the grid.
Still, the drop in performance of these three stations is surprising.
Tutka power station, the worst performing of the Eskom power stations, produces only a quarter (on average) of the power stated on its nameplate. Duba and Kendal each produce less than half of their original production.
Importantly, the following three worst-performing power plants are not: It's getting much better.
Kusile is the only one that has improved significantly from the numbers in the VGBe Energy report. Kusile lost three units in his 2022 when an exhaust gas duct (chimney) collapsed. It took about a year to restore them with temporary structures.
Tutuka
Tutka is a hopelessly broken power plant. At the time of writing the report (April last year), VGBe stated that “the plant has suffered numerous losses due to inadequate maintenance.”
“In April 2023, approximately 13% (461 MWe) of the 3,510 MWe installed net capacity was unavailable due to PLL.” [partial load losses]. An additional 67% (2,340 MWe) was unavailable due to full load loss (FLL) during the visit. ”
Read: Is Eskom doing more maintenance than under De Ruyter?
Part-load losses for the three worst-performing plants and Majuba total a whopping 3,000MW. This is the crux of the problem. In terms of partial load losses, the six worst performing stations totaled 4,000 MW, which corresponds to his four stages of load shedding.
Kendall
Almost ridiculously, Kendal's average PLL was nearly one-third of the previous year's production capacity.
The VGBe report makes clear: “Kendal has been reliable in the past, but over the past four years it has shown signs of aging and lack of proper maintenance. One of the plants had an EAF of 46% in 2022. Postponement of the overall overhaul has contributed significantly to the recent unreliable performance.
“Given that it has been in operation for 30 years and is expected to remain in operation for another 20 years, it will require mid-life rehabilitation.”
We can see that decisions taken in the late 2010s are now coming back to haunt Eskom. You can achieve a very decent EAF from the unit without maintenance, but at some point it will catch up to you. Those chickens come home to roost.
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Duba
According to the report, Duvha “has a history of more than 40 years.”
“Due to poor maintenance, the plant suffers from high load losses. In March 2023, almost 30 percent (780 MW) of the 2,875 MW (net) installed capacity was unavailable due to PLL One of the main elements contributing to PLL is the draft plant. Even when the ID fan is operated at full load, [induced draft] There is not enough capacity to ensure proper pressure in the furnace. This can be significantly reduced by tightening flue gas ducts and air heaters.
“We strongly recommend that you also inspect and re-pair any other potential sources of air ingress in your boiler.”
Majuba
Majuba's performance is amazing, although it is not one of the three worst performing plants. The report states matter-of-factly: “Although Majuba power station's age ranges from 22 to 27 years, due to poor maintenance, the power station is already suffering significant power losses.” .
“In April 2023, almost 40% (1,506 MWe) of the 3,807 MWe installed net capacity was unavailable due to PLL.”
1,500MW is basically a 1.5 step load shedding.
load loss
Eight of Eskom's 15 coal-fired power stations experience partial load losses of more than 400MW on average.
Fiscal year 2023 |
|||||||
Arnott | Duba | Kendall | Kriel | Majuba | Matimba | Matra | Tutuka |
458MW | 530MW | 1,077MW | 546MW | 938MW | 422MW | 408MW | 524MW |
Sticking to EAF “must be stopped immediately”
The report states that “an obsession with electric furnaces is a dead end and will lead to poor plant performance.”
- Over the past few months and years, outage and maintenance activities have been postponed to decommission, or at least maintain, the EAF.
- The operational priority of the Eskom coal fleet was not to restore power plants to a “new condition” after an outage, but to quickly resolve actual bottlenecks in generation capacity.
- Plants are forced to continue operating at the expense of technical conditions. Its effects are reflected in a large number of accidents, trips and partial load losses.
- This cycle is now gaining so much momentum that it could lead to plant collapse and further loss of production capacity. Appropriate maintenance and outage operations must be performed to shut down immediately, even if it means shedding a higher level of load for a limited period of time.
Importantly, it states that “up to 6000MW could be restarted at partial load loss (PLL) by correcting power plant deficiencies and applying prudent operation and maintenance practices.”
The level of planned maintenance has increased in recent months, so Eskom may just be playing catch up with this… let's take a look.
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