Return of Kusile unit one is great news, but how long will it remain in operation?

WHILE news of the return of unit one at the Kusile power station has been met with delight in many quarters, energy experts have warned of the possibility of a breakdown of the plant.

Power utility Eskom this week announced that it had made significant progress in its fight against load shedding, with the recovery of unit one at the Kusile power station after a year of being out of service.

Three units at the power plant went off-line in October last year following a mechanical fault.

Electricity Minister Kgosientsho Ramokgopa has indicated that four units that were off-line at the Kusile power station would return to service by the end of this year.

Units one, three and four are back online and, according to the minister's forecasts, unit five will be back in service by the end of this year.

This means the power plant's generation capacity has significantly improved due to the return of the units, resulting in lower stages of the rolling power cuts.

While Kusile is meant to be generating a total of at least 4,800 megawatts, unit one and three bring 800 megawatts each to the national grid.

However, energy experts say that the plant could easily break down, which would set the country back, once again, in its fight against the energy crisis.

“The plant can break down relatively easily, unfortunately,” said Professor Hartmut Winkler, an energy analyst at the University of Johannesburg.

“It is almost exactly a year now since Kusile lost three units. This is half of its capacity due to an unexpected flue duct collapse. Although Kusile and Medupi are new and would thus not be expected to break down frequently, they were built with significant design flaws. While some of these have been dealt with, the possibility of other things going wrong cannot be excluded.

“Then we have the older power plants, which may have once been operationally sound, but are now breaking down more frequently due to ageing and overuse.

“Given the size of the coal plants, the damage associated with some of the more serious breakdowns can be so severe that it puts a unit out of action for over a year.”

Energy expert Lungile Mashele agrees.

“The real challenge Eskom is facing currently is the variability of their plant performance” said Mashele.

“There is a 4,000MW swing in either direction, which is not optimal. Eskom needs to get this under control by getting to the root cause of plant breakdowns.”

News of the return of two more units, one at the Kusile, is great news, however, said Mashele.

“Kusile is very important, with each unit capable of producing 720MW net output. With the two units back online, that's 1,440MW additional capacity and a resultant reduction in load shedding.”

Mashele said South Africans could expect reduced load shedding now that we have the return of units at Kusile.

“We will definitely experience reduced load shedding, but it does not mean the end of load shedding. The supply deficit differs due to numerous reasons, such as seasonality and breakdowns. The current supply deficit averages 1,600MW (hence Stage 2 load shedding) - Eskom have also not solved for the evening peak demand, that is why Kusile is so vital.

“Lower stages of load shedding can be expected and will be reduced further with the return of the last of the three Kusile units and Medupi unit four in April 2024.

“There is also ongoing planned maintenance, so hopefully, this starts showing positive results in Q1 2024.”

In the past few weeks, South Africans have been blessed with minimal load shedding. Mashele said this was due to a number of factors.

“Load shedding has been reduced because of the return of Kusile, diesel usage, better plant performance and better maintenance, which may indicate better project management and quality control. They also have an adequate maintenance budget and have planned for their maintenance better.”

Winkler said the return of three of Kusile’s units were significant.

“Only three of Kusile’s six units have been recently restored. One further unit is still being fixed, while the last two units have yet to be commissioned,” said Winkler.

“Nonetheless, bringing three of its units back into operation adds 2,400 MW (equivalent to 2-3 stages of load shedding) to Eskom’s generating capacity.

“What is also important is that the repairs were done in the projected time, meaning that electricity supply over the summer period will be better than it might otherwise have been. Note, however, that the repair work for three of the inoperative units amounts to a ‘patch job’ that will result in much higher emissions and air pollution than would normally be allowed.

“At some point, this will have to be rectified, and the affected units will need to be taken off line again for lengthy periods.”

He said despite the return of half of Kusile’s units, South Africans will still experience load shedding.

“There will still be load shedding as the system continues to be constrained. Other units will now be taken off line to allow important maintenance work there. Eskom itself is projecting a high danger of load shedding for the next 12 months, and these projections were made on the basis that the repairs at Kusile would be successful.

“It is, however, possible that load shedding will be less intense in 2024 than it was in 2023.”

Winkler said it was vital that the power utility kept the Kusile plant running at optimal levels.

“Kusile has a maximum generating capacity of 4,800 MW. That is almost five stages of load shedding. Together with its equally large sister station, Medupi, these two stations should contribute almost 20% of South Africa’s electricity supply.

“Clearly, the performance of Kusile and Medupi are absolutely key to determining whether South Africa experiences power shortages or not. The fact that South Africa has drifted into the present power crisis is largely due to the delays (several years) in completing the construction of these two plants.

“The dire financial situation Eskom finds itself in now, and which makes it very difficult for them to respond effectively to the power crisis, is to a significant degree due to the Kusile and Medupi construction costing more than double the initial projected cost.”

He says various factors have played a part in reduced load shedding in the past few weeks.

“The arrival of spring, leading to far lower use of electric heating, always results in a drop in electricity demand. It has also helped that a lot of solar power installations have been completed this year – this has mitigated roughly one stage of load shedding.

“Another positive factor has been that Eskom has been able to curb sabotage to some degree – it seems to be less easy than it used to be to deliver sub-standard coal to the plants or to trigger breakdowns followed by the awarding of repair jobs to some unscrupulous contractors.”