Eskom is struggling to bring the three commercial units at its Kusile coal-fired power station in Mpumalanga back on load. Executives confirmed on Thursday that Kusile has not delivered any power to the grid since the weekend.
While progress has been made in replenishing emergency pumped storage and diesel reserves, Eskom still expects stage 2 load-shedding to continue until Monday morning.
By Thursday morning Kusile was supplying about 330MW after a decision was taken to bring the noncommercial Unit 4 on load. The plant’s three commercial units, when fully operational, can deliver 2,400MW. Unit 4 was connected to the national grid for the first time in December with the ability at the time to deliver about 330MW.
Eskom said in a media statement that on January 11, Unit 4 achieved full load of 800MW. After its testing and optimisation phase, it is expected to achieve full commercial operation by July 2022.
“Stage 2 load-shedding is assisting Eskom in replenishing its emergency reserves, and we trust that by Monday morning dams [at pumped storage stations] will be full and that that will assist us with challenges we may have in weeks to come,” Eskom COO Jan Oberholzer said.
But the big problem remains Kusile. “We have successfully returned to service the noncommercial unit; however, we have challenges with Kusile Unit 1,” he said.
Unit 1 at the power station has been down since last week, said Eskom’s head of generation, Phillip Dukashe, and while a lot of work has been done to resolve the problem, they “unfortunately do not have a solution yet”.
Oberholzer said on Thursday they were preparing to bring Unit 2 back on load after a long outage but warned of some difficulty in bringing it back to a level where it could “sustainably contribute to the capacity that we need”.
According to Dukashe, the plan was to have Unit 2 running by “sometime tomorrow”. The unit has been on a 75-day outage, mainly to correct a boiler defect.
Problems related to axillary steam boilers at Unit 3, which achieved commercial operation status in March 2021, would hopefully be resolved towards the end of the week or beginning of next week, Dukashe said. However, it was scheduled to go offline for a similar outage as Unit 2’s for two to three months.
Once completed, Kusile will be the world’s fourth-largest coal plant at 4,800MW plant consisting of six units of 800MW each. But the building of the Medupi and Kusile power stations have been besieged by delays, faulty construction and huge cost escalations.
Construction on Kusile started in 2008 and it was originally set for completion in 2015. Seven years later, only three units are in commercial service.
Chris Yelland, an energy analyst and MD of EE Business Intelligence, estimates that the “all-in cost” of the power stations now stands at about R520bn, double that originally planned. And yet the problems persist.
“[Kusile] is a new plant, it should be performing at 90% capacity. Instead it typically has availability of 30%,” Yelland said.
Apart from the corruption and mismanagement that plagued the construction of the power stations, they were poorly planned and executed. As a result, they suffer from “significant design problems”.
Among the many faults, Yelland highlighted the coal mills which must be reworked, and the boilers which were built 10m too low and were thus not suitably designed for the type of coal used at the plant. The faulty boiler design also had a knock-on effect on the proper functioning of the fabric filter system.
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