Eskom's take on avoiding blackouts this winter: 'extremely difficult'

5 May 2023

Eskom’s new head of generation, Bheki Nxumalo, has issued an update on the power utility’s ability to stave off higher stages of blackouts. It is the first time in weeks Eskom has given an update on the energy discourse, one that is usually dominated by Minister for Electricity Kgosientsho Ramokgopa and officials in the Presidency.

Eskom has predicted that the winter season in 2023 will be “difficult” as the power utility is set to enter the high electricity-demand months with more generating units at its power stations offline because of breakdowns.

Eskom’s new head of generation, Bheki Nxumalo, who is in charge of the performance of the utility’s 14 power stations, issued an update on Friday on the electricity system ahead of winter, the first since his appointment in early April 2023.

It was also the first time in weeks that Eskom has given a public update on the energy matter, a discourse usually dominated by the Minister for Electricity Kgosientsho Ramokgopa, and officials in the Presidency who are coordinating energy reforms. This is all while SA, in recent weeks, has been stuck vacillating between blackout stages four and six.

“It will be an extremely difficult winter,” Nxumalo said at a press briefing hosted by the Government Communication and Information System (GCIS) department, adding that Eskom was heading into the winter season with at least 3,000 megawatts (MW) lost to the power utility’s system because of breakdowns in generating units at its coal-fired and nuclear power stations.

Three generating units have been out of service since 23 October 2022 at Kusile Power Station, one of Eskom’s newest coal-fired power stations. That takes out about 2,100MW from generating capacity, which is equal to about stage two of load shedding. These units are set to be fixed and brought back into operation by December 2023, long after winter has ended.

For the first time in decades, Eskom will be approaching the winter season without a reliable generating unit at its Koeberg Nuclear Power Station, with several of its units taken offline for long-term maintenance.

Nxumalo said Eskom management and the board were finalising a plan detailing how the power utility would improve the performance of power stations during winter. With less than a month to go before the official start of the season, it is unclear when Eskom management and the board will go public with the plan.

Nxumalo said Eskom would still focus on the maintenance of its five worst-performing power stations (Tutuka, Kendal, Majuba, Duvha and Matla) to improve their performance, as measured by an energy availability factor (EAF), which is the proportion of Eskom’s plants available to dispatch energy.

A high EAF indicates that plants are well operated and maintained, helping Eskom to produce electricity cheaper. For Eskom’s current financial period, which runs from 1 April 2023 to 31 March 2024, the board has approved an average EAF target of 60%, which seems Herculean. Eskom’s EAF has been on a downward trend for a decade, reaching 84.5% in 2011, falling further to 66.6% by 2020, and now languishing at 56.3%.

Read more in Daily Maverick: Ramokgopa’s power plan to ease rolling blackouts could be undermined by Eskom’s diesel budget

A one percentage point improvement in the EAF, for example, can be transformative, improving Eskom’s generation capacity by 500MW, equivalent to nearly stage one of load shedding.

Short and long-term interventions to ease blackouts

At the GCIS press briefing, Ramokgopa peddled again the short-term interventions that he believes will ease or stave off higher stages of blackouts during winter.

Essentially, Ramokgopa and his Cabinet colleagues want Eskom to spend more money in 2023 by burning diesel (about R30-billion, from R21-billion in 2022) to run open-cycle gas turbines (OCGT) at Ankerlig and Gourikwa plants. The OCGT plants are usually used for dire emergencies and compensate for generation losses when there are breakdowns at Eskom’s power stations.

Underscoring how the OCGT plants will be pushed to prevent higher stages of blackouts and how their performance will be severely tested is a metric called load factor, which is an indication of how hard a generating unit is working just to produce electricity. Measured as a percentage, a load factor indicates the actual electricity or megawatt hour produced compared to the total installed capacity over the same time frame.

Eskom’s Nxumalo said the load factor at the OCGT plants is expected to be 20% during winter, rising from the current 11% – underscoring that the power utility will increasingly rely on burning diesel to momentarily keep the lights on. If fully used, OCGTs can avoid two stages of blackouts.

Even with an unlimited diesel budget, Eskom cannot burn more diesel than R30-billion owing to the physical and logistical constraints in transporting it to the OCGT plants. The plants can handle up to 100 diesel truck deliveries every day and not more. Ramokgopa said the government and Eskom were working on a plan to accommodate more trucks at OCGT plants.

Other aspects of Ramokgopa’s short-term interventions will focus on improving maintenance at Eskom’s five worst-performing coal power stations. Some additional power (about 1,000MW) will be imported from Mozambique and Botswana as Eskom has bilateral agreements with the countries to provide them and other countries in the Southern African region with electricity.

Ramokgopa also wants National Key Points including hospitals, communications infrastructure and police stations to be exempted from blackouts. A new feature of his blackout intervention would be installing devices that would enable municipalities and Eskom to remotely switch off the 8 million installed geysers at homes across the country. Remotely switching-off geysers for periods of between two and four hours a day has the potential to free up to 4,000MW, depending on the take-up of devices by households. Residential households consume 25% of electricity and contribute 35% during peak demand, through energy-guzzling devices such as geysers.

Other long-term interventions being considered by the government include extending the life cycle of coal-fired power plants, which poses challenges, ranging from more funding requirements for their maintenance and the government’s reneging on its commitments to richer countries to reduce emissions by retiring coal-fired power plants.

Read more in Daily Maverick: Why Ramokgopa’s plan to extend the life of coal-fired power stations will be a global challenge for Ramaphosa

The long-term plan also includes procuring more renewable energy from independent power producers. By June this year, the government plans to launch the seventh procurement round for more renewable energy from producers, about 500MW of solar and wind power. But this will be in provinces where it is easy to link and connect the renewable energy to the national grid such as the Northern Cape, the Eastern Cape, and Western Cape. DM/BM

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Short and long-term interventions to ease blackouts