Power utility Eskom has confirmed that an explosion at the Medupi power station's Unit 4 generator on August 8 has resulted in extensive damage to the generator.
Unit 4 had been on a short-term outage since August 6 and the explosion occurred during the displacement of hydrogen with carbon dioxide and air, respectively, for the purposes of finding an external leak.
Following a preliminary investigation, it appears that, while performing this activity, air was introduced into the generator at a point where hydrogen was still present in the generator at sufficient quantities to create an explosive mixture, which ignited and resulted in the explosion. It also appears that there was a deviation from the procedure for carrying out this activity.
No injuries were sustained, but Eskom has placed the employees who were responsible for managing and executing this work under precautionary suspension, pending the conclusion of a major event investigation.
Eskom last week reported that all six generating units at the Medupi power station, in Lephalale, were operational after a 14-year construction; however, it conceded that some work still needed to be done to address boiler design defects on some units. It expected that work to be completed within the next 24 months.
The planned flue gas desulphurisation (FGD) technology at Medupi has also not been installed.
Eskom planned to install FGD technology at Medupi by June 2025, as part of a legal covenant with the World Bank, which loaned the South African utility $3.75-billion in 2010 largely for the purposes of building the power station.
The technology would be used to lower the coal-fired power plant’s sulphur dioxide emissions in line with South Africa’s tightening minimum emissions standards.