By Lehlohonolo Lehana.
Eskom says it is on track to complete the repairs to the ducts in the west stack at the Kusile power station by December 2024, ahead of the March 31, 2025, deadline set by the Department of Forestry, Fisheries and the Enviroment (DFFE) when it last year authorised the use of temporary stacks that bypass the key pollution control system.
The state-owned power utility published an update on the use of temporary stacks at the power station, which South Africa’s National Air Quality Officer approved through a postponement of the Minimum Emission Standards (MES) policy in June 2023.
“The postponement allows Eskom to operate units 1, 2, and 3 without utilising the Flue Gas Desulphurisation (FGD) plant,” said Eskom.
“This plant is equipped with emission-abatement technology for SO2. The allowance extends until 31 March 2025, during which time the flue gas ducts in the permanent stack are being repaired.”
It said using these three units is critical to the Generation Operational Plan, as they contribute “a much-needed 2,400MW to the national grid”.
However, the postponement is subject to several conditions, including requirements for Eskom to mitigate the impact of SO2 emissions on air quality and public health in the region.
The power utility was also required to inform nearby communities of the potential environmental risks.
“To this end, several engagements have taken place and will continue until the permanent stacks are in place,” said Eskom.
The west stack was rendered inoperable when Kusile’s Unit 1 flue duct collapsed because of an uncontrolled build-up of slurry on October 23, 2022. The failure eliminated 2 100 MW of Kusile’s capacity from an already stretched system as units 2 and 3’s flues, which share a stack or chimney with that of Unit 1, were also damaged by the collapse.
In addition, Unit 5’s commissioning had been delayed by a fire incident, while Unit 6 was still under construction, leaving Kusile with only one operational unit, Unit 4, for an extended period.
The incident intensified loadshedding by two stages and contributed to 2023 being the country’s worst-ever year for power disruptions, which were implemented almost daily and at times at Stage 6, which involves some 6 000 MW of rotational cuts.
Eskom Group Executive for Generation Bheki Nxumalo also stated that emissions from the three units remained “below our atmospheric emission licence and ambient air quality limits”.
“We have implemented robust health screening initiatives within the surrounding areas and have installed additional ambient quality monitoring equipment to specifically monitor SO2 emissions, “Nxumalo added.
Emergency preparedness and response plans had also been developed, outlining processes and actions in the event of SO2 emissions exceedance incidents and for managing emergencies.
“Our onsite resources include a dedicated team of professional firefighters and emergency medical personnel, with a fleet of fully equipped ambulances and emergency response vehicles.
“We are also collaborating with the local authorities and several emergency scenarios have been mapped out and thoroughly prepared for.”