Eskom’s collapse shown in one graph

South Africa is experiencing its worse year of load-shedding because of poor power station performance and Eskom’s declining energy availability factor (EAF).

According to the load-shedding app EskomSePush, there have been 2,900 hours of load shedding so far this year. It translates to 121 days of load-shedding, more than double last year’s 48 days.

Eskom often blames ageing infrastructure for the poor performance of its generation fleet and the low EAF.

In 2020, Eskom’s generation executive Rhulani Mathebula said Eskom’s increased failure rate is not due to a lack of skills but because of unreliable and ageing infrastructure.

Eskom CEO Andre de Ruyter has also blamed ageing infrastructure for load-shedding, saying the older power plants are susceptible to failures and breakdowns.

However, an analysis by Daily Investor showed that the age of a power station does not automatically result in higher breakdown rates and a lower EAF.

To test Eskom’s claims, we compared the performance of Eskom’s Tutuka and Duvha power stations with two US-based coal power stations – Wansley and Scherer.

• The Duvah power station was first commissioned in 1980, with the final unit completed in 1984.
• The Wansley power plant in Georgia was first commissioned in 1976.
• Tutuka was first commissioned in 1985, with the final unit going online in 1990.
• The Scherer power plant was commissioned in 1982 and is of a similar age to Tutuka.

If Eskom’s claim of ageing infrastructure causing a significant deterioration in performance is true, the US and South African power stations should show similar trends.

A significant difference in performance points to other factors, like poor maintenance, mismanagement, and a lack of skills.

We used the energy availability factor (EAF) – the percentage of time the power station was available for use when it was needed – as a measure of performance.

From 2009 to 2021, Eskom’s Tutuka and Duvha had an average EAF of 64% and 56%, respectively. It means that since 2009 they were only available for 64% and 56% of the time they were needed.

In 2021, Tutuka and Duvha had average EAF of 37% and 44%, respectively. It is expected to be much worse in 2022.

Wansley and Scherer, in comparison, had an average EAF of 90% and 89%, respectively, over the same period. They were, therefore, available for 90% and 89% of the time they were needed.

An interesting observation is that Scherer and Wansley had an upward trend in their EAF figures as time progressed.

The large differential suggests that ageing infrastructure can still be reliable. With regular maintenance and using the latest technology, their performance can even improve.

In Eskom’s case, poor skills, mismanagement, and a lack of maintenance are the likely culprits for breakdowns and the low EAF – not ageing infrastructure.

The chart below shows the performance over time of the two power stations in the United States compared with Eskom’s Tutuka and Duvha.