(1)(a) The projected cost for the temporary stacks is estimated at R700 million excluding the operating and maintenance costs.
b) The construction of the temporary stacks for Units 1, 2 and 3 means that the flue gas from these units will not go through the flue gas desulphurisation plants, which reduces Sulphur dioxide levels. The Sulphur dioxide emissions from the temporary stack will thus be higher than would have been the usual case for these units.
The temporary stacks are built after the fabric filter plants and main boilers. As such, the particulate matter and nitrogen oxide levels of the units with the temporary stacks are no different from what they would have been in normal operations.
(2) To operate the temporary stacks with the higher than usual Sulphur dioxide levels, Eskom applied to the Department of Forestry, Fisheries and Environment (DFFE) for a postponement from the Minimum Emissions Standards (MES) published in terms of the National Environmental Management Air Quality Act (NEMAQA). Eskom received a postponement decision from the DFFE
on 5 June 2023. The Nkangala District Municipality issued a revised Atmospheric Emission Licence (AEL) reflecting the postponement on 13 June 2023. The applicable AEL limits for the temporary stacks are thus: particulate matter – 50 mg/Nm3, nitrogen oxide – 750 mg/Nm3 and Sulphur dioxide – 3500 mg/Nm3 (all measured at a 24-hour daily average)
Four parties appealed the MES decision, and three appealed the AEL decision. The Minister ruled on the MES appeals on 26 September 2023, allowing Eskom to proceed subject to three revised conditions. The District Municipality ruled on the AEL appeals on 28 September 2023, accepting the Minister's decision and allowing the project to proceed.
A key consideration in the process was that Eskom must ensure that the operation of the temporary stacks did not result in any health impacts on surrounding communities. The authorities approved Eskom’s plan to monitor and mitigate air quality impacts from Kusile on 18 September 2023. Eskom is implementing the approved plan.
(3) (a) There is no design defect associated with the existing West Chimney failure. The duct failure occurred due to overloading of the chimney flues and inlet duct. The repair is to restore the chimney to its original condition or as close as possible.
b) The projected cost for repairing the West Chimney will only be known once the stabilisation of the flues has been achieved.