Eskom’s coal plants hitting a cliff

Eskom’s coal plants are beginning to hit a cliff, and the number of breakdowns they experience is expected to increase due to the age of the power stations. 

This is feedback from the German consultancy group VGBE Energy, which the National Treasury commissioned to analyse the performance of Eskom’s coal-fired power plants and recommend how they can be improved. 

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 outlined why South Africans can expect load-shedding and problems at Eskom to get worse as the utility’s plants reach the end of their design life. 

Eskom cannot afford to let these plants be shut down as they provide critical generation capacity. Thus, it has chosen to try to extend the life of several power stations. 

For example, lifetime extensions are currently being discussed for various power plants, such as Arnot, Camden, Grootvlei, and Hendrina. 

Power plants are designed for a specific lifetime, which can vary from the design lifetime depending on the original quality and also on operation and maintenance conditions. 

However, coal-fired power plants are expected to have a service life of about 30 to 40 years for economic and technical reasons. Eskom’s 15 coal-fired power plants have an average age of 42 years. 

In reality, the components can very often be used much longer due to conservative assumptions of the design approach. 

However, detailed supervision of these components is required to identify creep damage prior to potential failure. 

Other parts of the plant are exposed to regular wear and have to be maintained or even changed to keep the plant reliably running. 

For the lifespan of a plan, one important influence is the quality of the operation and maintenance. 

The VGBE team explained that extensive renovations and upgrades can be performed during all stages of the station’s life, and the life of a power plant can be extended nearly indefinitely. 

However, economic or technological developments may cause also a well-maintained power plant to be decommissioned prematurely. 

If a proper maintenance approach is not followed over the plant service life, as is the case in the Eskom fleet, a lot of the equipment and components of the power plant are to be changed in a lifetime extension program after 40 years of operation. 

This costs a lot of money and requires the plant to be shut down for extensive equipment to be fully replaced. 

If the components are not fully replaced after a period of inadequate maintenance, the plants will experience increased breakdowns, and their performance will become more unpredictable. 

This is shown in the graph below, courtesy of the VGBE team. This graph outlines the rapid increase in breakdowns a coal power station will experience as it ages – the lack of maintenance exacerbates this.