Eskom warns of project risk at Koeberg

A report from Eskom warns of the impact of a delay on the multi-year project to extend Koeberg’s lifespan by another 20 years.

According to the Grid Code, Eskom is obliged to submit a medium-term system adequacy forecast on an annual basis. The aim of these reports, according to the utility, is “to assess, over a five-year period, the risks of power outages that could arise based on foreseeable trends in demand and generation capacity in South Africa”.

Its latest report warns that a two-year delay in the Koeberg project “will further exacerbate power shortages and result in massive amounts of unserved energy.” This scenario was included as realistic in its medium-term outlook on system adequacy, it said, “based on recent developments.”

Normally, the country’s only nuclear power plant would reach the end of its 40-year lifespan in 2024. To extend this, it has launched a mammoth project to replace the steam generators on both blocks.

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A total of six of them have to be replaced. A regulatory process is also ongoing, with an application being filed with the National Nuclear Regulator.

Eskom originally planned to replace the unit 2 steam generator during the refueling outage starting in January. This was postponed as delays in completing the work – which were realistic – posed a “significant risk” to the network.

In the end, delays in restarting the unit after refueling and a far less complex parts replacement than with the aborted steam generators meant that it was resynchronized to the grid four months later than planned.

No room for slip

Unit one is due to be shut down soon for the replacement of its three steam generators and is expected to be shut down for at least eight months. A similarly long outage is planned for block two at the end of next year.

In reality, there’s little to no room for slip-ups on either project. The scenario in Eskom’s report illustrates the consequences of shutting down unit one in July 2024 and unit two in November 2025.

Such a delay means that Eskom will require an additional 15 TWh (terawatt hours) per year – in excess of the required energy – without changing the schedule for this project.

In practice, 1,860 MW of power will be missing, which corresponds to two stages of load shedding.

The utility has already publicly stated that it urgently needs an additional 4,000MW to 6,000MW of generation capacity, which needs to be connected to the grid as soon as possible. This would increase these numbers to between 6,000 MW and 8,000 MW.

However, the report warns that its baseline scenario is “no impact” on Koeberg’s nearly 2,000 MW by 2027. In other words, the steam generator replacement projects at both blocks are expected to be completed within the required timelines and no delays in the regulatory process.

The report, rather cautiously, recommends that the utility “place more emphasis on extending the lifespan of Koeberg, as the loss of Koeberg units would significantly impact adequacy in the short term.”

The load shedding gets worse

Aside from Koeberg, the report effectively confirms that blackouts will get worse over the next five years.

The worst case scenario – with its coal fleet struggling at current levels and reasonable demand growth – shows a gap of 18 TWh next year. This supply gap corresponds to the entire Matla power plant or 3,450 MW.

But while the commissioning of the outstanding Kusile units sees this improvement in this scenario by 2024, it steadily increases to 30 TWh in 2027. This is due to the planned shutdown of two units at Kriel, four at Arnot, eight at Camden and six at Hendrina, and two at Grootvlei over the next five years (most between 2025 and 2027).

At best, the gap is between a roughly balanced system (in 2024) and 9 TWh in 2027. To achieve this, the utility needs to increase its Energy Availability Factor (EAF) from an average of 58% to 67%. An EAF target of 75% was set for the Executive Board in particular.

Maintenance doesn’t work

The report is somewhat damning of the results Eskom‘s Reliability Maintenance Program, which aimed to undertake major modernization and maintenance to improve the performance of (particularly) the coal fleet.

It said the trend of outages has continued to increase, suggesting that “the…program, in its current form, may not be delivering the desired results.”

“It is vital that the current conservation regimen is reviewed to improve its effectiveness.”


These scenarios exclude any new renewable capacity beyond the five outstanding confirmed projects — one solar photovoltaic (PV) plant, one concentrated solar power (CSP) plant, and three smaller projects announced in June this year under the Contingency Procurement Program were signed. Once these are all connected to the grid (by early 2024), a further 300 MW will increase the installed base of renewable energy to 6,430 MW.

(The impact of private power generation projects has also not been taken into account).

If 10 GW of capacity is added under Renewable Energy Independent Power Producer Procurement (Reippp) program bid windows 5 through 8, the worst-case scenario gap narrows to between 7 TWh and 9 TWh from 2024 onwards. However, this projected capacity is the most recent Integrated Resource Plan (2019) is simply not enough to fill the gap.

Much depends on the interventions announced by President Cyril Ramaphosa, which will see allocated capacity doubled to 5,200 MW in Bid Window 6, as well as significant increases in future bid windows.

This article originally appeared on Moneyweb and has been republished with permission. Read the original article here.

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