Eskom state of the system
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In its state of the system briefing today, Eskom shared with the public its plan to continue with its accelerated maintenance programme during the summer period, the peak maintenance season, to improve power system reliability.

Since September, Eskom has increased its planned reliability maintenance programme to an average 5,500MW of capacity. While this is comparable to the amount of maintenance carried out in the period between September 2020 and March 2021, it is almost double the average maintenance carried out in the same period from September 2019 to April 2020.

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“Our objective is to achieve a reliable and sustainable generation plant, thereby reducing the risk and frequency of the occurrence of loadshedding. As such, Eskom will not compromise on reliability maintenance and mid-life refurbishment,” said Eskom Group Chief Operating Officer, Jan Oberholzer. “However painful in the short term, this maintenance we have to do in order to ensure future reliability.”

Through the accelerated reliability maintenance programme, Eskom hopes to reduce loadshedding

The accelerated maintenance programme has borne fruit, with Eskom managing to limit loadshedding to a minimum during the winter period. Since 1 April 2021, loadshedding was implemented for 32 days. This includes the 11 days of loadshedding implemented since September.

The Generation division has been characterised by unsatisfactory performance, with output from the power stations below target. This is caused by a faster deterioration in generation units that have not yet enjoyed reliability maintenance.

Eskom concedes that loadshedding carries a significant damaging effect on the economy. Year to date, the energy availability factor (EAF) has declined to 65%, against a target of 70% EAF. A key contributor to the low EAF was the high levels of planned maintenance during the summer months. However, there has also been an increase in unplanned outages during this period.

“We are aware that the increased maintenance does elevate the probability of loadshedding in the short term, but this is necessary to improve the future performance of the generation fleet,” said Oberholzer.

Oberholzer further emphasised the urgent need for an additional 4,000MW to 6,000MW generation capacity on a sound financial justification to complement the Eskom available capacity. This is required to eliminate the risk of loadshedding and to ensure the necessary electrical energy that is needed to stimulate the economy.

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Performance of the Koeberg Nuclear Power Station

While these concerns with the generation performance persist, the Koeberg Nuclear Power Station is operating optimally. Unit 2 of the power station has been operating for the whole year without interruption since completing its last refuelling outage in October 2020.

In January 2022, Koeberg Unit 2 will be shut off for the steam generator replacement (SGR), regular refuelling and maintenance. The SGR will enable Koeberg to operate for a further 20 years beyond 2024. The formal application to extend the operating license has been submitted to the relevant regulatory authority and has been accepted for processing.

Koeberg Unit 1 tripped on Sunday morning as a result of a fault on a feedwater pump, which is on the secondary plant. The plant was shut down in accordance with standard plant operating procedures and all parameters are stable.  There are no nuclear safety concerns on the reactor side of the plant, which is ready to be restarted once the feedwater pump fault has been resolved.

The investigation into the feedwater pump fault is in progress and once concluded, Eskom will be able to confirm the return to service date of the unit, which is expected to be during next week.

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Coal stock levels and risks of wet coal

On the coal front, Eskom maintained healthy coal stock levels across its generation fleet, with an average of 48 days’ worth of coal stockpiled at its power stations. This compares favourably with the Grid Code requirement to hold at least 20 days’ worth of stock.

Eskom is making a concerted effort to continue improving its coal handling ability to reduce the risk of wet coal incidents during the coming rainy season. While there has been a good improvement on this key performance area during the past rainy season, more investments to enhance the wet coal strategy still need to be done.

Reliability maintenance programme at the Medupi Power Station

The work done so far to correct the design defects at the Medupi Power Station has resulted in a steady improvement and reliability of the Medupi Power Station generation units. This work has also commenced at Kusile with some of the major design defects already corrected on Unit 1.

There were some notable strides in several aspects of the operations. A unit each at Medupi and Kusile power stations achieved commercial operation during this year, adding 1,594MW to the grid. Kusile has now reached 50% completion, with three of the six units commissioned.

The successful completion of Medupi suffered a blow as Unit 4 (720MW) of the power station experienced a generator explosion on 8 August 2021. This was just a week after the last of the six units were officially handed over to Generation on 31 July 2021. Eskom experienced another major setback on 11 September 2021 when Kendal Unit 1 (640MW) generator transformer caught fire. Both units remain offline, which puts further strain on the power system.

Kendal Unit 1 is expected to return to service by end of this year while the return to service date for Medupi Unit 4 has not yet been determined.

The capacity outlook for the period ending August 2022 shows that the power system remains constrained. Eskom will be required to extensively use the Open Cycle Gas Turbines (OCGTs) to either avert loadshedding or to reduce the magnitude thereof.

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Eskom says it will continue to communicate frankly and promptly should there be a need to implement loadshedding.

The Distribution and Transmission divisions have also attained positive technical performance, with a lower number of interruptions. Since April 2021, a total of 38,256 households have been connected to the grid versus the target of 34,742 houses.

However, increasing theft and vandalism of cables and substations continue to negatively impact operations and system reliability. Electricity theft continues to pose not only operational and financial challenges to Eskom but also a public safety risk.