Load-shedding is back
Eskom begins stage-4 power cuts nationwide
Eskom’s mega power stations Medupi and Kusile, which were intended to alleviate SA’s power constraints, have a multitude of serious design and technical flaws that are impeding their operation.
The poor performance of the new stations is a key reason that Eskom is still unable to meet the country’s energy demands despite adding 3,200MW of capacity to the grid since 2015. Eskom's current installed capacity is 38,000MW.
The utility went into stage 4 load-shedding mode on Monday, dropping 4,000MW from the grid, the largest ever amount that it has needed to shed to keep the grid stable.
Two of the six generating units that failed on Monday, causing the jump to stage 4, were at Medupi.
Eskom said the main problems at Medupi and Kusile are the fault of the main contractor on the boilers, Japanese conglomerate Mitsubishi Hitachi Power Systems Africa (MHPSA). It is not the first time that Hitachi’s work on Medupi has been found to be defective. In 2013, 10,000 welding faults were discovered when Hitachi failed to heat-treat the welds.
In 2015, it failed the crucial steam test, which is a necessary step before commissioning.
In 2015, Hitachi and Mitsubishi Heavy Industries merged to form MHPSA.
Hitachi’s award to build the boilers has always been controversial due to it’s partnership with the ANC’s investment company Chancellor House.
In 2015, it was fined by the US Securities Exchange Commission for paying the ANC front a $1m (R13.8m) success fee and $5m (R69.1m) in “dividends” in connection with the Medupi and Kusile contracts.
A multiplicity of faults have been identified common to both Medupi and Kusile.
In its updated tariff application to the National Energy Regulator of SA (Nersa), Eskom lists seven technical and design problems.
These include: the boiler design results in high temperatures, leading to frequent tripping; the design causes excessive ash accumulation and ash bags must be frequently replaced. This causes ash blockages, tripping and load losses.
None of the coal mills meet technical specifications and must be serviced twice as frequently as normal.
The gas air heaters do not meet technical requirements. The dust-handling plant, which is vital for safety, environmental and occupational health reasons, requires more frequent maintenance due to high ash accumulation, leaks and the scarce availability of spare parts.
The distributed control system frequently fails, causing plant trips. Lastly, there is a high number of vibrations on the cooling loop.
Several of these problems are adversely affected by poor coal quality.
The presentation also lists a shortage of skilled people and unavailability of spare parts.
The result of the problems has meant that Medupi’s unit 6 (the first of three so far commissioned) has barely reached 60% of its capacity since June 2018. The remaining two units perform at 70% capacity.
In response to questions last week, Eskom’s chief operating officer Jan Oberholzer laid most of the problems at the door of MHPSA, which he said were being managed through the terms of the contract. Eskom has assembled teams of specialist to rectify the major defects and technical workstreams have been established with contractors.
MHPSA spokesperson Nicolas Meyer said the company did not wish to comment.
In another blow to the plants, Clyde Bergemann Africa – a main contractor to Eskom for the ash- handling systems and a sub-contractor to MHPSA – has filed for business rescue on Monday. Employees walked off the site at Medupi and Kusile after they were not paid for the month of January.
In 2015, it was fined for paying the ANC front a $1m (R13.8m) success fee and $5m (R69.1m) in ‘dividends’