No loadshedding this summer, we hope, says Eskom

September 4th, 2019, Published in Articles: EE Publishers, Articles: Energize


Jabu Mabuza

Eskom says no loadshedding since March and the synchronisation of the final generating unit at Medupi shows that its turnaround strategy is working. Speaking at the power utility’s latest State of the System briefing recently, Jabu Mabuza, the chairman and acting group chief executive, said that the utility’s nine-point plan is bearing fruit. No loadshedding was implemented during the winter period, and while no loadshedding is expected over summer the risk remains as the system is still tight and vulnerable, Mabuza said.

While electricity demand in summer is generally lower than in winter, the summer period comes with its own challenges. The change in customer electricity consumption in summer means sustained demand throughout the day and not just over the evening peak as people use air conditioning for cooling. He commended the generation team for keeping the lights on through winter and said that everything possible would be done to ensure that the country would not be exposed to loadshedding this summer.

Here is the core of the utility’s message to the public:

Winter performance (April to August 2019)

  • No loadshedding over the last 164 days.
  • All six units at Medupi generating power.
  • Koeberg and peaking plant are performing well.
  • Transmission and distribution networks are working reliably.
  • Diesel and coal stocks are up.

Objectives for summer months (September 2019 to March 2020)

  • Avoid loadshedding.
  • Execute an average of 5500 MW of planned maintenance.
  • Keep unplanned plant breakdowns below 9500 MW to safeguard against loadshedding.
  • Drive sustainable transmission and distribution network performance.
  • Encourage public participation and energy saving initiatives.

Click here to download the presentation

Mabuza announced that the utility had avoided loadshedding since March, and that Eskom’s achievement of an electricity availability factor (EAF) of 70,4% during the winter months, while not being as high as it should be, was commendable. He said that an EAF of 78 to 80% was possible “in the not too distant future”.

He said that loadshedding had been averted by the fact that demand was lower than previous years as a result of a warmer winter, the economic downturn, and the willingness by certain large energy users to reduce demand.

Summer, Mabuza said, will be a challenging time for Eskom because it’s the season when most of its maintenance work must done, but also a time when demand increases due to the heavier use of airconditioners. For this reason, there may still be a risk of loadshedding during the summer months, although the utility will resort to its hydro- and diesel-powered peaking plants to prevent it.

This year, Mabuza said, 5500 MW worth of generating capacity will be taken offline for necessary maintenance. If, while this amount of capacity is offline, unplanned outages exceed 9500 MW, loadshedding would become necessary to prevent the entire system from failing.

In his presentation, Jan Oberholzer, Eskom chief operations officer, said that many of the necessary factors to reduce outages have been – or are being – addressed. For example, the necessary stockpiles of coal at all but three power stations (Kriel, Medupi and Kusile) was up to 50 days’ worth; and the fuel tanks at the utility’s diesel-powered peaking plants are full. He said that although the management team’s objective was to avoid reintroducing loadshedding, the utility could not definitively say that loadshedding would not be reimposed.

Factors which could cause the reintroduction of loadshedding include:

  • New trips and plant breakdowns (e.g. boiler tube leaks, etc.).
  • High vacuum levels due to high temperatures (Matimba Power Station).
  • Delays in returning plant to service after a planned outage (outage slip).
  • Macro factors such as protests, adverse weather or strike action could further impact plant performance.
  • The use of emergency resources for consecutive days, could impact dam levels and diesel fuel stock.
  • Increased theft and vandalism could impact network performance.
  • Severe weather conditions impacting imports.

All six of Medupi’s units are producing power, Oberholzer said. The final unit to be synchronised, Unit 1, was still being tested and checked but it was producing power. In all, this 4800 MW power station is now producing slightly over 4000 MW. There are still some design-error issues associated with the boiler, he said, but the engineers on site are finding work-arounds to keep the plant operational.

Although the power utility is congratulating itself on the start-up of the final unit at Medupi, this power station, which should have been completed and handed over to the system operator in 2013, will most probably not be ready for hand-over (called the “commencement of operation date” – COD) for another year because of the inherent problems in the construction of the plant, as well as other problems which are yet to be discovered. Thus, the power station will be about eight years late. Furthermore, the cost of construction will have ballooned from the original budget of R80-billion to R230-billion or more by the time the official COD is reached.

Over and above the flaw in the boilers, the power station’s flue-gas desulfurisation (FDG) equipment has not been installed yet. FGD is a requirement of the terms under which the World Bank loaned Eskom about R56-billion for the Medupi project. Oberholzer said that FGD equipment would probably cost the utility an additional R39-billion, taking the total well over R250-billion by the time is has been completed.

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