/ 16 January 2023

Focus on improving the energy availability factor as a quick win to stop load-shedding

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There is no doubt that the future of electricity generation will be largely renewable energy and possibly nuclear energy. Photo: Supplied

There is no doubt that the future of electricity generation will be largely renewable energy and possibly nuclear energy. But in the short to medium term the South African electricity grid will be largely powered by coal-based electricity generation. The Integrated Resource Plan (IRP) of 2019 captures the roadmap and policy direction adopted by South Africa. A lot has changed since 2019, and hence the IRP 2019 is being reviewed. 

It was assumed that the Eskom fleet energy availability factor (EAF) would be maintained above 70% whereas today it is consistently below 60%. Renewable energy costs have come down substantially, but there is a need to consider the cost of introducing large energy storage systems to support grid stability and make up for the performance of intermittent/variable renewable energy. 

In addition, future updates of the IRP would have to take into account the changing characteristics of the power system, mainly because of the introduction of renewable energy and energy storage systems. Besides modelling for EAF and power generation in megawatts (MW), the issues of power system grid stability and the location of new plants would have to be taken into account. 

Getting the IRP 2019 reviewed, consulted and approved will take time. Meanwhile, urgent steps need to be taken to address the load-shedding and baseload crisis. Some have argued that South Africa has enough capacity to cater for the current demand (and that is true when considering Eskom’s installed nominal capacity) but the low EAF evidently shows that even with sufficient installed capacity, the security of supply is threatened if plant performance is poor.

According to the latest system update report from Eskom, the electricity grid has about 55.4 gigawatts of installed electricity supply capacity, excluding demand side products or instruments. This is broken down as follows:

  • Dispatchable capacity (including imports and emergency generation resources): 49.2GW
  • Solar photovoltaic (non-dispatchable): 2.3GW
  • Concentrated solar power (non-dispatchable): 0.5GW
  • Wind (non-dispatchable): 3.4GW

The highest peak demand in 2022 was 31.8GW which was recorded on 2 June 2022. For the rest of the year, the peak demand ranged between 23GW and 26GW. Therefore, the electricity system has enough installed capacity to cater for the demand, operating reserves and maintenance (planned and unplanned outages). So the big question is what has happened, from a technical point of view, that led to frequent load-shedding in 2022 as depicted in Figure 1 below? What is behind the sharp increase in unplanned capacity loss factor (UCLF) and the drastic drop in EAF as depicted in Figure 2 below? 

Figure 1: Loadshedding statistics from January 2015 to December 2022 (Source: EskomSePush)

Figure 2: Technical performance of Eskom Generation fleet from FY 2007/8 to FY 2022/23 (Data source: Eskom)

The assumptions and projections for energy availability factor as the IRP bear reference (see Table 1 below). It was projected that EAF will be at 73.5% in 2022. Surprisingly the actual EAF as of December 2022 was 58% (per the Eskom Weekly System Status Report 2022, week 52). It is acknowledged that Eskom has had a number of non-technical problems over the last 10 years or so, including allegations of corruption and criminal activities. But there are technical issues that must have contributed to this sudden drop in EAF and these are unpacked below.

Table 1: Projected Eskom Plant Energy Availability Factor (IRP 2019)

PORT REX97.7193.0792.46
BIG 1066.7867.1867.69
TOTAL RTS63.2155.8161.24
CURRENT FLEET TOTAL71.0071.5371.40
NEW BUILD75.3178.2984.00
ESKOM TOTAL71.572.5073.50

What happened in the recent past?

To understand what has happened in the recent past, one has to look at the energy availability factor trend since 2008, when load-shedding started (see Table 2 below and Figure 2 above).

Table 2: Technical performance of Generation fleet (source: Eskom Audited Annual Reports and System Status Report for Week 52; Note FY22/23 is from Jan 2022 to Dec 2022)

The above table clearly demonstrates that the problem of increase in plant breakdowns started in about  2013, indicated by a sudden increase of unplanned capacity loss factor from 7.97% in 2012 to 12.12% in 2013. The UCLF worsened in 2014 and 2015, with figures of 12.61% and 15.22%, respectively. To address this negative trend in UCLF, it appears that the planned capability loss factor (PCLF) was ramped up in 2016 and 2017, as can be seen from the figures of 12.99% and 12.14%, respectively. The result of this increase in PCLF was observed in the drop of UCLF in 2017 to 9.9% from the previous high UCLF observed in 2013 (12.12%), 2014 (12.61%), 2015 (15.22%) and 2016 (14.91%). 

Unfortunately, the high PCLF was not maintained in 2018, 2019 and 2020. It is only in 2021 that the PCLF starts to increase to 12.26% (perhaps as a reaction to the catastrophic worsening of unplanned capacity loss factor to nearly 23% in the financial year 2019-20). For the year 2022, the PCLF was again dropped to 10.23. UCLF averaged about 25.35% for 2022. For the current financial year, 2022-23 the EAF is at 58% and UCLF at 29.82, which is the worst performance in the history of Eskom. 

The reduction in the planned capability loss factor is the root cause of the current challenges Eskom is facing today regarding load-shedding. It is common knowledge that when you are operating an old fleet, maintenance is typically higher than when operating a relatively new fleet of assets. It is puzzling how Eskom got this wrong.

Furthermore, it would also appear that the effectiveness of the maintenance that is being done is not great. This is an observation borne by the fact that the planned capability loss factor  bump of 12.26% has had no effect in even arresting (let alone reversing the trend) in the unplanned capacity loss factor deterioration seen in subsequent years. 

This seems to indicate that we have officially arrived at that place known as being between a rock and a hard place. This seems to suggest that plant condition has deteriorated so badly that it will require a step change in planned capability loss factor (removing a substantial amount of capacity for maintenance) for quite some time to catch up with all the maintenance required to restore plant condition to a relatively good state. This will also require painstaking attention to the quality and priorities of the maintenance.

As a result of inadequate plant maintenance, Generation is also now incurring a daily average of about 5 000 megawatts to 7 000MW of partial load losses. Common problematic plant areas across the fleet include the following: milling plant because of poor coal quality; gas cleaning; draught group; poor condensing caused by poor vacuum (hot air in summer and cooling water system blockages in condensing pipelines that has negatively affected effective heat transfer and cooling water temperatures); air heaters and high stack emissions. 

In addition, station demineralised water chemistry consumption is above target because of plant leaks. High demineralised water consumption places an unsustainable burden on the water treatment plant to produce sufficient demineralised water to satisfy the station demand, resulting in chemical excursions (and further knock-on effects of plant deterioration). 

Furthermore, again because of inadequate maintenance of the plant, emissions performance has deteriorated. Load is sometimes curtailed to ensure that minimum emissions standard (MES) limits are met or not substantially exceeded. This requires the plant to be operated under abnormal conditions or reduced load, which sometimes requires manual operating interventions. As a result dust and ash handling plants experience problems associated with hoppers not being emptied timeously and abatement control plants being damaged. This mode of operation also results in fabric filter plant systems (FFPS) and electrostatic precipitators (ESPs) facing issues of blinding of fabric filter plant (FFP) bags, and contamination of the ESP fields caused by fuel oil/unburnt carbon carryover.

About half of these partial load losses can be cleared online or during weekend maintenance opportunities, provided spares and contracts are in place. The rest (about 3 000MW) require extended outages to clear or plant modifications. With increased focus and commitment, it is possible to lower partial load losses to be consistently below 5 000MW within six months, and thereafter to be consistently below 4 000MW within 12 months. This focus and commitment is currently a problem and most stations’ resources are consumed with keeping the units running. To ensure a drastic reduction of partial load losses, a different approach is required. Attending to partial load losses at the coal face is required, as opposed to tracking and reporting.

Of course, there are other contributory factors that must also be considered, such as leadership that may not be equal to the task, exodus of technical skills, corruption, criminal activities at the power stations, coal quality issues and staff morale.

Urgent steps to be taken

The following nine urgent steps are proposed:

  • The President immediately declare a National State of Disaster for electricity supply empowering Eskom and the government to take extraordinary measures to stop load-shedding. This may include quick procurement of critical spares from around the world. The state of disaster would also enable the mobilisation of support from other power utilities around the world. A National Electricity Supply Command Council to be set up to provide oversight.
  • Eskom executive committee to urgently approve and release a maintenance budget per power station for the next five years. This maintenance budget must be aligned with a high PCLF (15%, but preferably much more). To accommodate this high PCLF, load-shedding at about stage 3 level, may have to be implemented for up to 12 months. This is to allow for units to be taken off the system for general overhaul and much-needed refurbishments. This approach will require an agile procurement process to allow for quick procurement of critical spares and maintenance crew. What is untenable, at this stage, is for the country to be subjected to severe load shedding that goes on without addressing (or even allowing a worsening of) the underlying root causes of capacity shortage, just to manage from one crisis to the next.
  • Outsource maintenance to original equipment manufacturers (OEMs) using risk-benefit type of long-term contracts (minimum 10 years). This must be accompanied by proper scoping of the outages, making sure critical spares are available before breaking open, and ensuring an acceptable quality of workmanship during an outage. The OEMs to be held accountable for outage slips and unit performance beyond the outage. If the outage slips or unit trips occur after returning from an outage or a unit breaks down due to poor workmanship post-outage, the OEM must face economic penalties for each hour of downtime or load loss. Having a well-defined system of holding OEMs accountable for plant performance, and the consequences that go with it, will compel the OEMs to have the right skills in place and ensure high quality of workmanship. By the same token, if the unit performs well after an outage, the OEM and staff must be rewarded.
  • Establish site-based recovery teams for plant maintenance oversight (made up of Eskom specialists and independent specialist engineering companies), reporting directly to the power station manager. The site-based maintenance recovery teams must be empowered to make decisions without having to write endless memorandums and motivations to head office managers and committees. The manager must be the final decision-maker during this recovery. As a minimum, the scope of work for the site-based recovery teams should entail driving maintenance (be it on breakdowns and/or planned) quality control and engineering assurance, ensuring correct spares are specified and procured, and ensuring outage scopes are correct. These site-based teams must also provide technical support to the buyers of equipment; ideally, buyers must be engineers or technicians trained in procurement processes and governance. Priority power stations (which are large and complex) for these site-based teams should be the following:
    • Kusile (50-year life; shutdown estimated to be by 2073)
    • Medupi (50-year life; shutdown by 2071)
    • Majuba (50-year life; shutdown by 2050)
    • Kendal (50-year life; shutdown by 2043)
    • Matimba (50-year life; shutdown by 2041)
    • Lethabo (50-year life; shutdown by 2040)
    • Tutuka (50-year life; shutdown by 2040)
    • Duvha (50-year life; shutdown by 2034)
    • Matla (50-year life; shutdown by 2033)
    • Kriel (50-year life; shutdown by 2029)
    • Arnot (50-year life; shutdown by 2029)
  • Establish site-based partial load losses recovery teams (made up of Eskom specialists and Independent specialist engineering companies), reporting directly to the power station manager. The site-based teams must, similarly, be empowered to make decisions without having to write endless memorandums and motivations to head office managers and committees. Themanager must be the final decision-maker during this recovery. As a minimum, the scope of work for the site-based recovery teams should cover implementing interventions to reduce partial load losses, process engineering and trouble-shooting, conducting in-depth investigations and analysis of unit trips, proactive identification and technical management of single point of failures, handling security technical matters and providing primary energy oversight (coal quality, diesel management and accounting, fuel oil management and accounting). Priority power stations for these teams would be the same as those mentioned for the maintenance recovery and oversight teams.
  • Establish site-based recovery teams for environmental compliance and minimum emissions standard (MES) upgrades (made up of Eskom specialists, independent specialist engineering companies and original equipment manufacturers), reporting directly to the power station manager. The site-based teams must be empowered to make decisions without having to write endless memorandums and motivations to head office managers and committees. The manager must be the final decision-maker during this recovery. Some of the technologies to be considered were highlighted in the opinion piece published by Mail & Guardian recently, headlined “Practical Steps to stop load-shedding”. These include retrofitting emissions abatement technologies for sulphur removal, nitrogen oxide (NOx) reduction, and particulate removal. Deployment (through public private partnerships) of clean coal technologies such as the use of green ammonia (produced from green hydrogen and nitrogen) for removal of sulphur from coal combustion flue gas, producing ammonium sulphate fertiliser as a saleable by-product. Profits from selling ammonium sulphate could then be used to fund the retrofits of low NOx burners and the proven high-frequency power transformers for the removal of particulates. The existing electrostatic precipitators and dust handling plants must be upgraded accordingly.
  • Mass recruitment of technical skills (including learners, artisans, technicians, engineers and highly-experienced specialists). This recruitment process must be site driven, with the final decision-maker (on the numbers and mix of required skills) being the power station manager. Headhunting and external recruitment to be part of the recruitment strategies employed at the site, without needing approval from head office.
  • Use of local universities and universities of technology to conduct investigations. Outcomes and recommendations from these investigations must be practical and implementable. This must be done under the guidance of Eskom Research, Testing and Development (RT&D). In fact, RT&D needs to function as a world-class research organisation that earns its living from implementable solutions that make a difference in the performance of Eskom’s plants and infrastructure (almost similar to earning revenue from licencing solutions and patent royalties). Technical training must be rolled-out per power station and accredit system engineers, technicians, plant managers, artisans, operators and so forth.
  • Reinstate incentive scheme for staff, irrespective of the financial position of the organisation. Without a motivated workforce, no plan will work. This intervention is crucial to get buy-in from Eskom guardians, especially organised labour. Having a proper performance management system, that is aligned with the strategic direction of the organisation and key performance indicators, will help.
  • Daily updates provided through the Eskom spokesperson regarding progress to stop load-shedding. Daily updates to be structured as follows:
    • Immediate steps (which is basically covered in this opinion piece)
    • Short-term interventions
    • Medium-term interventions
    • Long-term interventions

One of the main factors contributing to the root causes of a sudden increase in load-shedding is not sustaining maintenance for the old fleet, particularly from 2018 to 2020. There was an attempt to increase PCLF in 2021, and again this was not sustained in 2022. It is therefore not surprising that the breakdowns seem to have breached the roof in 2022. It is pleasing to see that Eskom increased maintenance during December 2022, notably PCLF reaching the highest ever in Week 52 at 16%. These high levels of PCLF must be maintained at this level and more for at least the next six months or so. Other measures and interventions as articulated in this opinion piece must be implemented immediately to ensure sustained improvement in technical plant performance, most likely to be realised toward the end of 2023. Unfortunately, the situation will get worse before getting better. It is important to protect the grid stability during the next six months. If the issue of grid stability is not taken seriously, then perhaps it is time to start planning for the worst-case scenario –– a complete blackout.

The views expressed are those of the author and do not necessarily reflect the official policy or position of the Mail & Guardian.