The collapse of Eskom’s coal fleet

Eskom’s collapse can be shown in one graph, with the decline of the Energy Availability Factor (EAF) of its coal-fired power stations coupled with a sharp increase in partial load losses at those plants.

This was revealed by the German consultancy group VGBE Energy, which the National Treasury commissioned to analyse the performance of Eskom’s coal-fired power plants and recommend ways to improve them.

The German engineers, who have extensive experience running coal-fired power plants, spent four and a half months studying South Africa’s ailing power utility.

They went through Eskom’s coal fleet, plant by plant, to determine what changes the utility should make to improve the performance of the individual stations.

The VGBE team also compared Eskom’s plant performance to coal-fired power stations in European countries to illustrate just how poorly the utility’s plants have been maintained in recent years.

The main objective of the coal fleet investigation was to find out the reasons for the coal fleet’s low Energy Availability Factor (EAF), which hovers around 51%, and develop measures to improve the situation.

They identified several overarching issues, such as Eskom’s complex management system, inadequate maintenance, and low staff morale, as reasons why the utility’s performance has declined.

Another factor is the general incompetence and lack of ability to implement theoretical knowledge in practice.

However, the VGBE team also flagged the rising partial load losses at Eskom’s coal-fired power stations as a key driver of their performance deterioration.

During the engineers’ four-and-a-half-month study, partial load losses hovered around 6,000 MW. Partial load losses refer to the electricity generation capacity lost on any unit due to faults causing it to operate at less-than-optimal capacity.

The VGBE team collected data from Eskom regarding the EAF of its coal-fired power plants and their partial load losses from 2010 to the end of the 2023 financial year.

This data showed a strong correlation between the declining EAF of the coal fleet and the rise in partial load losses.

“During the site visits, it was observed that outage scopes are not completed sufficiently for a unit to return at full load,” the VGB team said.

As a result, the magnitude of partial load losses (PLLs) has not improved after maintenance and, since 2018, has only been getting worse.

The correlation between the reduction in EAF and an increase in PLL is clearly illustrated below.

This article was first published by Daily Investor and is reproduced with permission.