PRETORIA – Eskom just declared another power emergency – the fourth in the last eight days – and another evening of load shedding seems to be looming.
This comes as Eskom’s biggest industrial customers are asking serious questions about the utility’s ability to deal with a total or partial collapse of the electricity system.
The utility however says it is not taking any chances and institutes load shedding to prevent such an event. However, the protocols are in place and simulations are being done in the unlikely event that it does happen, Eskom spokesperson Andrew Etzinger told Moneyweb.
The increasing frequency and magnitude of unplanned outages at Eskom’s power stations is of grave concern to its members, Intensive Energy Users’ Group (IEUG) spokesperson Shaun Nel told Moneyweb.
On Monday almost 22% of Eskom’s installed generation capacity of 43 000 was out of service, 3 838MW being planned outages and 5 600MW unplanned outages.
The IEUG is very concerned about the high percentage of unplanned outages, which it says should have declined as Eskom increased its planned maintenance during the summer months. The National Energy Regulator (Nersa) has earlier also expressed its concern and said Eskom does not seem to get the benefit it should from its planned maintenance.
The utility had to resort to load shedding three times in the past week as demand outstripped supply.
Nel said the reality is that Eskom cannot predict when or how much of its generation capacity will fail at any given time. It is therefore necessary to ensure Eskom is prepared for a system collapse. “We want to know how they will go about re-energising the system, what they will do from the moment the system fails, how they will restart, how they will communicate, everything,” he said.
Nel said he does not expect a total system collapse in which case it may take up to two weeks to get the electricity supply restored. He said the collapse of sections of the system is more probable, in which case it will be important to contain the situation and prevent it from spreading to other parts of the grid.
The IEUG will meet representatives of Eskom this week to discuss the utility’s readiness.
Andrew Etzinger, Eskom spokesperson, said Eskom takes the risk of system collapse very seriously and does not take any chances in the way it manages the grid.
He said while painful, when Eskom declares an emergency and resorts to load shedding the whole purpose is to protect the grid from collapse. It follows the national standard that has been developed and is strictly regulated by Nersa in this regard. After every event it has to report fully to Nersa and explain all aspects, including why certain units were off-line and how the issue was communicated.
He said the way the system is designed, it also has some automatic under frequency load shedding capability to protect the grid.
Etzinger said in a worst case scenario it may take two weeks to get the system back on track. Power stations also need electricity to operate; therefore they will all fail when a system black-out occurs. Certain power stations have black-start capacity. This entails the start-up of a power station using for example diesel. Part of the preparations for a possible system collapse is black-start testing. This is done as part of the simulations Eskom does to ensure its readiness, Etzinger says.
Asked why Eskom is only planning on decreasing its planned maintenance in July, while the biggest demand last year was in June, Etzinger said last year was an exception. The second half of the winter is usually colder and planned maintenance will be ramped down to below 2 000MW in July.