Load-shedding is not only frustrating to households but is a scourge upon the country’s economy – with many businesses either unable to operate in load-shedding or forced to purchase backup power systems to continue doing so.
Nevertheless, neglecting to manage the grid in this way given the current state of the generation system could spell even greater disaster.
Since the current output capacity of Eskom’s generation is not always capable of meeting the electricity demand in South Africa, load-shedding is necessary to prevent an imbalance in the system.
A large part of this important task lies with the team of workers at Eskom’s Simmerpan National Control Centre (NCC) in Germiston, Gauteng.
Why load-shedding cannot be avoided
Eskom told MyBroadband that while there had been multiple instances of blackouts and small-scale brownouts in other countries, South Africa had not suffered the same fate since load-shedding started 14 years ago.
It said itself and several other operators in the southern hemisphere had a precarious predicament – they are isolated.
“Everybody else has got connections to other utilities, so if there are problems they would typically be able to get help from another network, which we can’t do,” Eskom said.
While other countries have not had to implement load-shedding despite their own generation issues and flare-ups, they had a backup in the form of neighbouring system operators.
Eskom, by contrast, has much larger installed capacity than any of the foreign operators connected to its wider network in the rest of Africa.
Angola, Botswana, DRC, Eswatini, Lesotho, Malawi, Mozambique, Namibia, Tanzania, Zambia, and Zimbabwe combined would not be able to support South Africa in helping to bring the system back online in the event of a blackout.
Big team and resources
In order to keep the power system in balance, the generation output is changed every four seconds to match customer demand.
Eskom said that the team managing the broader system that falls under the system operator is much larger than just those within the National Control Centre.
It is made up of around 400 people, which includes engineers, technicians, and computer scientists, working across the sectors of national control, technical operations, the grid code, and demand response.
Most of these employees have either BTech or BSc qualifications, Eskom said.
A large part of the Technical Operations team’s work involves the creation of models to forecast factors like anticipated demand, generation, and impacts on the system due to changes such as new power suppliers coming online.
Network planning at the control centre is forecasted two years ahead, two weeks ahead, and on the day. There is also a retrospective analysis which looks at how the forecast differed from what was realised.
Aside from the highly skilled workforce that helps monitor the system, Eskom employs Energy Management System software that can perform automatic load-shedding in cases of severe, unforeseen capacity loss.
In order to ensure that changes can be implemented without delay, the utility even has its own dedicated telecommunications network – which it said was bigger than any of the mobile network operators’.
“If the guy in the control room pushes the button to open a breaker in Cape Town, he does so on the telecommunications network,” Eskom said.
Inside the IGCC
Given its critical role in keeping the grid stable, the Simmerpan National Control Centre is currently under very strict COVID-19 health and safety protocols.
As a result, MyBroadband was unable to visit the facility but was instead invited to the Integrated Generation Control Centre (IGCC) at Eskom’s Megawatt Park Head Offices.
While this does not boast the real-time controlling capabilities available at the NCC, it provides a snapshot of the same information that the Control Room has at its disposal.
At the time of our visit, Eskom had around 20,000MW of installed capacity which was unavailable due to planned maintenance and unplanned outages, and it was conducting stage 2 load-shedding.
What we saw
In the room, a large display made up of multiple screens presented detailed information on all the power stations which form part of Eskom’s generation capacity.
One screen showed bar graphs for each of the powers stations with the current MW supply of each individual unit relative to the total capacity installed at that station.
For example, the Medupi power station showed only one unit out of six was online and generating 421MW of electricity out of a capacity of 4,371MW.
This was because coal supply was constrained as a result of heavy rain of the time, leaving five units unable to generate electricity.
Other screens showed the status of each unit that supplies power to the grid, with specific explanations given for any outages.
Another screen showed a graph with the real-time electricity demand, which had dropped significantly after Eskom implemented Stage 2 load-shedding at 12:00 in the afternoon.
Eskom’s general manager for production showed us that he was capable of viewing the exact status of each power plant’s various components – including turbines and extractor fans – directly from his office.
The images below show the real-time overview of the power system which can be seen in the IGCC at Eskom’s head offices.