Eskom believes it can avoid exceeding stage 4 load-shedding during the 2023/2024 summer period, due to the return to service of several major generators in the coming months.
However, even in its best-case forecast, it anticipates between 11 and 19 days of load-shedding per month will be necessary up to March 2024.
During its latest State of the System briefing on Wednesday, 27 September 2023, the utility said it should be able to keep capacity losses due to breakdowns below 14,500MW during the holiday period — December 2023 and January 2024.
“There is a higher level of confidence in meeting the revised summer UCLF+OCLF [unplanned losses] projection as these are primarily based on returning Kusile [coal power station] units with further gains possible through the execution of other stations’ recovery plans,” Eskom said.
Eskom’s head of generation, Bheki Nxumalo, told the media the utility aims to add 2,880MW capacity from four units at Kusile in the next three months.
This should be enough to offset nearly three stages of load-shedding.
The first 2,160MW will originate from the return of units 1, 2, and 3 in October and November 2023.
These three units have been offline for about a year due to the collapse of a section of the flue duct in October 2022.
Unit 3 is planned to be the first to return to service on 14 October 2023.
However, the units are being brought back using a temporary setup that will not be able to reduce emissions like the primary flue-gas desulphurisation system, which will take longer to repair.
The temporary solution is pending final environmental approval from local and district municipalities. The Department of Forestry, Fisheries, and the Environment has already given its approval.
Nxumalo said that Eskom should get final feedback on environmental approvals by Thursday, 28 September 2023.
“All the contracting work [on Unit 3’s temporary stack] is completed, we are just waiting for the approval to come through,” Nxumalo said.
The return to service of units 1 and 2 is planned for November 2023.
In addition, Kusile Unit 5 is expected to be synchronised to the grid for the first time to add a further 720MW of capacity by the end of December 2023.
Koeberg not expected to help with outlook
The 900MW Koeberg Unit 1 is also expected to return to service on 3 November 2023, after its stream generator replacement is complete.
However, it is not expected to have a net-positive effect on generation availability because Unit 2 will be taken down only a few days later for its life extension.
Nxumalo said the utility expected Unit 2’s replacement turnaround to be shorter than Unit 1, thanks to the lessons learned with the first unit’s replacement.
Unit 1 was initially supposed to be back online in June 2023, in time for the higher winter electricity demand period.
Eskom is again using three unplanned load loss scenarios for its load-shedding forecast for the spring and summer months from September 2023 to March 2024.
However, it has increased the load loss assumption for each scenario by 1,500MW, taking into account how last summer’s assumptions drastically underestimated unplanned losses.
Under the best-case scenario, which assumes a load loss of 14,500MW, Eskom anticipates 116 days on which load-shedding must be implemented.
The most common load-shedding stage experienced under this scenario will be stage 4, with between 11 and 19 days of load-shedding every month.
In the medium-risk scenario, which assumes 16,000MW of losses, Eskom expects to implement load-shedding on 187 days out of the 213 days.
In that instance, the most common load-shedding stage will be stage 5, and the highest stage 6.
Under the worst-case assumption, Eskom forecasts a load loss of 17,500MW and 211 days of blackouts, with regular stage 6 load-shedding and a maximum of stage 7.
The table below summarises Eskom’s load-shedding outlook for the summer 2023/2024 period.