Medupi unit 4 explosion repair update

Unit 4 of Eskom’s Medupi power station suffered a devastating explosion on 8 August 2021 and repairs were expected to take just over two years. However, Eskom now estimates that the unit will return to service on 31 August 2024.

Medupi began operating in 2015, seven years after construction began, with unit 4 coming online in 2017.

When fully operational, Medupi will be the fourth largest coal power station in the world with each of its six units producing 720MW.

If fully operational, Medupi would mitigate four stages of load-shedding.

Medupi is yet to be fully operational, with units 5 and 6 only operating at partial load due to design defects.

On 8 August 2021, during a short-term outage for maintenance, Medupi unit 4 experienced an explosion that caused extensive damage. Miraculously, there were no fatalities.

An investigation found the workers had failed to purge the generator of hydrogen before it mixed with oxygen, which resulted in a massive blast when it was ignited.

Zweli Witbooi, acting plant manager at Medupi, said the incident “seems to indicate procedural non-compliance and management failures”.

Eskom has suspended nine employees after the initial investigation, four of whom were senior-level employees and the other five were managerial.

Repair update

Medupi’s recovery manager, Tshepo Molabe, said that the damage is substantial, but it could have been worse if the turbine was operating at full load.

Former Eskom CEO Andre de Ruyter estimated the bill to repair Medupi unit 4 to total R2.5 billion.

According to Witbooi, the event was insurable, so some costs will be recouped through insurance claims.

Eskom’s latest update admits that the repair is taking longer than expected, but progress is being made.

The property damage assessment has been completed, and the original-equipment manufacturers have submitted a proposal outlining the repair process to Eskom.

One of the reasons why the repair is taking longer than expected is that Eskom will also be fixing design flaws in unit 4 during the repair process.

These flaws include sub-standard boiler tubes, insufficient ducting, and filters not performing to their specifications.

Original-equipment manufacturers will be used to fix these defects and ensure that they operate to the correct performance specifications.

The cost to repair these defects is estimated to be R300 million, which is an additional cost to the R2.5 billion repair.

Eskom, when asked for an update on the progress of Medupi’s repair, said that unit 4 is estimated to return to service by 31 August 2024.