In this opinion article, Sasol senior VP for the Sasolburg & Ekandustria operations Rightwell Laxa, and Sebenzana MD Andrew Carr, argue that old, coal-fired power stations similar to those used by Sasol and Eskom could achieve a much-needed maintenance turnaround by blending dwindling engineering expertise with a high-tech, asset management platform. The authors outline how boiler-tube failures at the Sasolburg power stations were reduced by more than 66% and how the old power stations are now achieving world-class performance levels.

In an Op-Ed article published in the Daily Maverick in January this year, energy expert Chris Yelland argued that even as South Africa transitions to a low-carbon future, a culture of proper reliability maintenance of all plants – including existing coal-fired power stations, boilers and associated power generation equipment – is urgently needed.

While exciting renewable energy projects steal the limelight, the reality is that legacy coal-fired energy assets still account for 83% of South Africa’s energy mix and are the bedrock of the region’s electricity supply industry. In his article, Yelland pointed out that of Eskom’s 15 coal-fired power stations, 13 are at an average age of 42 years and some will need to be decommissioned soon. By comparison, parts of energy and chemicals group Sasol’s Sasolburg fleet have been in operation for close to 70 years.

Old power stations can become unreliable, unpredictable and deliver poor performance if they have not been well operated and maintained throughout their life. These legacy energy generation assets are critical for our region to power the economy while we work out our transition to greener energy sources. The region needs a stable backbone while new renewable energy assets and an updated transmission system are developed and implemented.

In 2016, Sasol also experienced increasingly unreliable production from its own fleet of 12 old coal-fired boilers that are crucial to production at its Sasolburg facility. Working closely with local services firm Sebenzana, Sasol agreed to test a radical, new, high-tech approach to enhance maintenance decisions across the boiler fleet. Sasol agreed to allow Sebenzana to deploy its Smart Asset Management Platform, SAMP for short, for the collection of all relevant data relating to the boiler fleet.

The information was then collated and synthesised through the platform to generate relevant maintenance insights for better asset performance decisions. Sebenzana has been heavily involved in the development of its high-tech asset management platform since its involvement in the European Union’s RIMAP process and a related extensive rollout of a RIMAP-based Risk Based Inspection (RBI) process for managing critical pressure equipment. At its heart, the platform uses both historical and arising online and offline data collected from multiple sources, an RBI-type engine, advanced algorithms and even machine learning to enable maintenance engineers to make better decisions. Such insights are only useful if they ensure effective asset decisions, and the SAMP platform helped create such insights – which have proved crucial in the subsequent dramatic performance turnaround of the Sasol fleet. Only four years ago, Sasol was experiencing about 25 boiler-tube failures a year on a rolling 12-month average across a fleet of 12 boilers.

Now, in early 2022, the number of failures has been reduced to seven per annum – a result that is considered a “world-class” boiler operations and maintenance achievement. The Sasolburg experience highlighted a tendency to overestimate what can be achieved in the first year of a maintenance turnaround and underestimate what is possible by leveraging better data and decision-making over a longer three to four-year time horizon. It also showed that when it comes to critical infrastructure assets like the boilers, turbo generators, mills and cogenerators used to produce the country’s electricity, what is critical is maintaining them well to deliver on their original specifications over the length of their planned, and usually extended, lifecycles. What has been proved with the boiler maintenance project at Sasol is that new technology, when linked to both internal and external expertise, can help ensure that critical maintenance outages are executed with greater precision.

The technology has enabled experienced engineers to make the very most of these outages with a systematic process that emphasises the most critical requirements first, based on the history and characteristics of that particular plant or piece of equipment. Crucially, the platform also incorporates a monitoring function during the long periods when the plant is online and running day and night, sometimes for years. This monitoring is sensitive to the fact that each piece of equipment, even those from the same manufacturer, tend to run slightly differently. This enables the collection, storage and synthesis of critical data about the condition of individual plant assets. Telltale signs of equipment under stress or imminent failure are, therefore, easier to identify proactively assisting with focused maintenance spend. When it comes to critical assets, making good decisions is like compound interest: it’s the small consistent efforts and ever-improving decisions that end up delivering a compounding return in terms of asset performance.

The Sasolburg experience shows that no matter how difficult the situation may appear, including at Eskom currently, there are sufficient skills and expertise available that can be leveraged to improve the performance of assets that remain so important for powering the country.