Eskom warns of Koeberg project risk

A report by Eskom has warned about the impact of a delay on the multi-year project to extend Koeberg’s life by a further 20 years.

Under the Grid Code, Eskom is required to file a medium-term system adequacy outlook annually. The objective of these reports, says the utility, is “to assess over a five-year period the electricity supply shortfall risks that may arise based on foreseeable trends in demand and generation capacity in South Africa”.

Its latest report warns that a two-year delay on the Koeberg project “will further exacerbate the power supply constraints, leading to massive amounts of unserved energy”. This scenario has been included as a realistic one in its medium-term system adequacy outlook, it says, “based on recent developments”.

Ordinarily, the country’s only nuclear plant would reach the end of its 40-year design life in 2024. To extend this, it has begun a mammoth project to replace the steam generators on both its units. In all, six of these need to be replaced. There is also a regulatory process underway with an application having been filed with the National Nuclear Regulator.

Eskom had originally planned to undertake the steam generator replacement on unit two during its refuelling outage from January. This was postponed as any delays in completing the work – which were realistic – posed “significant risk” to the grid.

Read: Winter worries: Eskom defers Koeberg steam generator replacement to August 2023

In the end, delays in bringing the unit back online after refuelling, and a far less complex part replacement than the aborted steam generators, meant it was still resynchronised to the grid four months later than planned.

No room for slippage

Unit one is scheduled to be taken offline soon for the replacement of its three steam generators and is expected to be offline for at least eight months. A similar long outage is planned for unit two at the end of next year.

In reality, there is little to no room for slippage on either of these projects. The scenario in Eskom’s report illustrates the consequences of a shutdown of unit one in July 2024 and unit two in November 2025.

Such a delay means Eskom will need an additional 15TWh (terawatt hours) of supply per year – over and above the energy needed without any shift in timelines on this project.

In practical terms, there will be a shortfall of 1 860MW of capacity, equivalent to two stages of load shedding.

Already, the utility has publicly stated that it urgently needs a further 4 000MW to 6 000MW of generation capacity to be added to the grid as soon as possible. This would push those figures to 6 000MW to 8 000MW.

The report does, however, caution that its base case is for “no impact” on the nearly 2 000MW from Koeberg between now and 2027. In other words, it expects the steam generator replacement projects at both units to be completed within the required timelines, as well as no delays in the regulatory process.

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

Read: South Africa’s nuclear sector has failed its test

Load shedding will get worse

Aside from Koeberg, the report effectively confirms that power cuts will worsen over the next five years.

Its worst-case scenario – with its coal fleet struggling at current levels and reasonable growth in demand – shows a gap of 18TWh next year. This shortfall in supply is equal to the entire Matla Power Station, or 3 450MW.

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

In the best-case scenario, the shortfall ranges between a roughly balanced system (in 2024) and 9TWh in 2027. To get to this requires the utility getting its energy availability factor (EAF) up from an average of 58% to 67%. The board, notably, has been given a target for EAF of 75%.

Maintenance not working

The report is somewhat scathing of the results of Eskom’s reliability maintenance programme which aimed to do deep refurbishment and maintenance to improve the performance of (in particular) the coal fleet.

It says the trend of outages has continued to increase which “suggests the … programme in its current form may not be yielding desired outcomes”.

Read:
Eskom’s maintenance work not yielding results: Oberholzer [Sep 2022]
Eskom COO sees another 18 months of South Africa outages [Oct 2022]

“It is crucial the current maintenance regime is reviewed to improve its efficacy.”

Renewables?

These scenarios exclude any new capacity from renewables beyond the five confirmed projects outstanding – a solar photovoltaic (PV) plant, a concentrated solar power (CSP) plant, as well as three smaller projects signed in June this year under the emergency procurement programme. Once all of these are connected to the grid (by early 2024), an additional 300MW will take the installed base of renewables to 6 430MW.

(It has also not included the impact of private generation projects).

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

A lot rests on the interventions announced by President Cyril Ramaphosa, where the allocated capacity in Bid Window 6 will be doubled to 5 200MW, as well as substantial increases in future bid windows.