Eskom, which imposed rolling power cuts again until further notice on Sunday, will be unable to meet the electricity needs of the country over the next five years, its latest statutory assessment of the power system showed.
SA has been faced with chronic power supply constraints for more than 10 years and 2022 has been the worst yet, with a record number of days, and consecutive days, of planned power cuts.
A recent report by Eskom paints a worrying picture of what is to come, with the power company stating that “the situation will worsen as the plant performance of Eskom’s fleet continue[s] to trend downwards, power stations shut down and demand grows”.
Eskom’s medium-term system adequacy outlook, released at the end of October, uses available information about expected electricity supply and demand scenarios over the next five years to inform electricity users about the power system’s ability to meet demand.
The latest report, which covers the period from 2023 to 2027, shows that even under the most generous assumptions of low demand, the timely addition of new generation capacity and improved power station performance, the system will not be able to fully meet demand.
The worst-case scenario will see the energy supply gap increase by 40% over the next five years.
The low-demand forecast will see electricity demand decrease by 0.3% on average per year, while the moderate-high scenario predicts a 1% average annual growth rate linked to a GDP growth rate of about 1.9%.
To complete the outlook, these demand forecasts are compared with plant performance assumptions and they take into account that Eskom’s generation fleet is expected to reduce by 5,288MW between 2023 and 2027 because of plants reaching their turbine dead-stop dates.
Eskom’s energy availability factor (EAF), which measures output as a share of total installed capacity, has for much of this year run at 62%-65% and at times it has been about 50%, well below its target of 74%.
In the report, Eskom predicts EAF will range between an average low of 58% and an average high of 67% towards the end of 2027.
Maintenance
The EAF, averaging 67%, assumes that maintenance planned in the Reliability Maintenance Recovery Programme will be able to arrest the decline in plant performance.
But, as Eskom admits in the study, its maintenance plan has “not been yielding desired outcomes” as shown by the recent increase in unplanned outages at various power stations.
The worst-case scenario will see the supply gap widen from 18 terawatt-hour (TWh) in 2023 to 30TWh in 2027.
Eskom explains in the report that an energy gap of 18TWh is equivalent to the generation output by Matla power station at full load. The station has installed capacity of about 3,500MW.
If additional generation capacity, as set out in the Integrated Resource Plan of 2019, is rolled out according to plan, it will help narrow the supply gap to about 8TWh in 2027, but the study shows that the envisaged pace of implementation of new generation capacity of about 10GW (much of which will be from renewables) will not be enough to fully remedy the supply constraints.
“Given that the EAF is the biggest lever to system adequacy and the statistically determined trend reflects a further downward trajectory, it is crucial the current maintenance regime is reviewed to improve its efficacy,” the report says.
Two urgent risk factors to the system outlook that will further diminish power supply were not built into the system outlook scenarios presented in the report. They are delays to the life extension project of the 1,860MW Koeberg nuclear power station in Cape Town and the possible implementation of minimum emissions standards.
A decision made by the department of forestry, fisheries & the environment in November 2021 to rein in emissions from Eskom’s coal-fired power stations would require an immediate shutdown of 15.9GW of coal-fired generation capacity and about 30GW by April 2025. This decision is now under review pending further public stakeholder meetings, which will conclude early next year.
But if the decision stands, Eskom warns that it “will have a significant negative impact on Eskom’s mandate to supply stable and reliable electricity for the country’s needs”.
Koeberg
The report also discusses the possible repercussions of a two-year delay to the Koeberg life extension programme “based on recent developments”.
Koeberg’s units 1 and 2 were both scheduled to be offline for six months in 2022 for maintenance and refurbishment work. However, due to the delays on unit 2, the maintenance outage for unit 1 has been moved to December. Some of the maintenance work that had been scheduled to be performed on unit 2, such as the replacement of its three steam generators, has been delayed until the next planned outage schedule for August 2023.
Koeberg’s operating licence will expire in 2024 and certain upgrades, such as the replacement of the steam generators on units 1 and 2, are required by the National Nuclear Regulator to extend the operating life of plant by 20 years.
If the Koeberg life extension is delayed by two years, it will “severely constrain the system and exacerbate [power supply] inadequacy” and result in a loss of 15TWh per year.
The report does not consider possible upsides, such as the impact on power supply from Eskom’s land-lease scheme to independent power producers in Mpumalanga as well as the initiatives being driven by the national energy crisis committee, which was appointed to see to the implementation of interventions announced by President Cyril Ramaphosa in July to end load-shedding.
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