Another huge blow for Eskom

 ·3 Nov 2022

Power utility Eskom has warned that unit 1 of its troubled Kusile power station will be down for months following a critical failure.

On 23 October 2022, a section of the Kusile Unit 1 operation failed while it was offline for repairs, Eskom said.

The technical explanation given was that a section of the flue gas duct – the equivalent of a chimney in a household – exiting the sulphur dioxide absorber failed on the horizontal rubber expansion joint as well as the compensator – a bend to direct flue gas up the chimney and allow for thermal expansion of the chimney – whilst the unit was on forced shutdown for Flue Gas De-sulphuration (FGD) recirculating pump repairs.

The power utility said that investigations and assessments are in progress to establish the cause of failure and to ascertain the extent of the damage, as well as the recovery scope of work.

“While it is uncertain at this point, it is anticipated the unit may remain offline for a few months, and this duration shall become clearer over the next few weeks. Access to the area has also been restricted as part of precautionary measures,” Eskom said.

The group said that it is consulting with various specialist stakeholders, including the original equipment manufacturer, to determine the best course of action to restore the plant as quickly as possible.

“The failed section of the Unit 1 flue gas duct is located inside the flue chimney. The ducts are made from steel sections welded together and surrounded by a windshield, which is made of reinforced concrete that also houses the Unit 2 and Unit 3 flue gas ducts.”

Unit 2 was off load at the time while Unit 3 was generating electricity. Unit 4, whose FGD duct is housed on a separate flue chimney, is currently on load generating full load to the national grid, it said.

“As part of precautionary measures put in place, the return to service of Unit 2 has been put on hold while Unit 3 continues to run at stable load,” Eskom said.

The failure comes at a critical time for Eskom, as constant breakdowns in its ageing fleet have pushed the country into a near-daily load shedding for the past three months. All-day load shedding is currently being implemented, with more expected to come.

2022 has been the worst year for load shedding on record in terms of duration and in terms of the highest stages reached.

Kusile and the other new-build in the fleet, Medupi, were supposed to be the reliable replacements for Eskom’s older power stations which are reaching or will be reaching their end of life over the next few years – however, they have ended up being even less reliable.

Unit 4 at Medupi, which suffered a catastrophic hydrogen explosion in 2021, remains offline and is only expected to return to service in September 2024.

On 17 September 2022, Eskom said it experienced a fire in the gas air heater of Unit 5 of Kusile during a commissioning exercise. The utility noted that a similar fire in Unit 2 happened a few years ago, which resulted in a 12-month delay. Because of this, the group said that it would likely only get Unit 5 online by December 2024.

Unit 6 at Kusile, meanwhile, is expected to only be completed by May 2024.

Delays and overruns

The new builds have suffered many delays – they are still not 100% complete – and have blown past their initial budgets by billions of rands.

The Medupi project began in 2007 and has faced numerous delays while running over budget. The first of the project’s units attained commercial operation status in August 2015. The plant was initially expected to be fully completed in 2012.

Work at Kusile, meanwhile, began in 2008, with the first synchronisation taking place in 2017, three years after the original completion date.

In terms of budget, Medupi and Kusile had an initial budget of R79 billion and R81 billion, respectively. In 2020, the Eskom board approved budget revisions to complete the power stations, giving R145 billion for Medupi and R161.4 billion for Kusile’s build.

The latest update from Eskom is that the power stations will be fully completed in 2023 and 2026, for Medupi and Kusile, respectively.

According to Eskom, R126 billion and R147 billion of the revised 2020 budget have been spent, leaving R19 billion and R14 billion remaining. To date, no additional costs have been incurred, it said.

The reason for the delays at the plants is due to technical issues and major plant defects, Eskom said. These are system or equipment defects that result in or have the potential to, significantly reduce the Energy Availability Factor of multiple units, and where the available contractual defect resolution remedies have not been effective.

Read: Fresh delays at Medupi and Kusile amid eye-watering costs

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