Koeberg licence extension needed to ensure system stability, says Eskom report

Tuesday, 8 November 2022

State-owned utility Eskom, in its capacity as system operator, is required to publish every year a review of the adequacy of the integrated power system to meet the requirements of electricity consumers. The Medium-Term System Adequacy Outlook Medium-term System Adequacy Outlook (MTSAO) assesses the electricity supply shortfall risks that may arise based on foreseeable trends in South African demand and generation capacity over a five-year period. The latest edition - MTSAO 2022 - was published on 30 October and covers the calendar years 2023 to 2027.

Eskom's two-unit Koeberg plant is the only nuclear power station in Africa, and according to World Nuclear Association, produces around 5% of South Africa's electricity. The plant's two 900 MWe pressurised water reactor units were connected to the grid in 1984 (unit 1) and 1985 (unit 2) and were originally licensed for 40 years of operation. Eskom has applied to the country's National Nuclear Regulator to extend the plant's operational life by 20 years, to 2045.

MTSAO 2022 considers the impact of possible delays of two years to Koeberg's life extension, which it says is "based on recent developments". The resulting loss of generation would be 1,860 MWe - or up to 15 TWh per year, leaving the system "severely constrained" if the units have to shut in accordance with the original 40-year life of plant, it says.

Eskom has already deferred the replacement of Koeberg 2's steam generators - part of the work needed to underpin the long-term operation of the plant - so the unit could return to service to help meet high winter demand earlier this year. The steam generator replacement had been scheduled to take place during a planned refuelling and maintenance outage that began in January, but will now not be able to take place until its next scheduled refuelling and maintenance outage in August 2023.

Possible delays to Koeberg's life extension are identified as "sensitivities" in the report, which says that disruptions to South Africa's "already fragile power supply" will have a detrimental effect on the ability of the system to provide secure and reliable electricity to the consumer. "The MTSAO 2022 study shows that delays to the extension of the operating licence of Koeberg will further exacerbate the power supply constraints leading to massive amounts of unserved energy," it notes.

The report recommends that "more emphasis" should be placed on extending the operating life of the nuclear power station, "as the loss of Koeberg units would significantly impact adequacy in the short term".