Eskom Chief Operations Officer Jan Oberholzer said Stage 4 load shedding will give the power utility enough space to build up fast-depleting emergency reserves and avoid the risk of implementing Stage 6 load shedding.
Stage 4 load shedding was implemented on Wednesday morning following a barrage of breakdowns, shutdowns and trips at power stations across the country. This includes the loss of about seven units in one night, which left the power system under severe pressure.
“We again do apologise for the difficult situation we are placing the people of South Africa in and the negative impact to the economy. However…in order to protect and ensure the integrity of the electrical system, proactive implementation of load shedding is required,” Oberholzer said.
Compounding Eskom’s challenges are the 16 generating units, which Oberholzer said are currently “running at risk” – putting a further 5800MW of power at low to high risk.
Challenges faced at power stations has left the power utility overly reliant on its emergency supplies which are dams/pump storage facilities and its 14 open cycle gas turbines at Ankerlig and Gourikwa power stations.
Furthermore, he explained that with reserves running low, implementing Stage 4 load shedding became critically important.
“Eskom and the Independent Power Producers have 3000MW of open cycle gas turbines installed on the system. Should we run out of diesel at these power stations, this capacity would not be available to supply the demand and would necessitate a further three stages of load shedding to be implemented.
“Similarly, our pump storage generation [dam] capacity is…2700MW and if the dam levels were to be completely depleted, this would require a further three stages of load shedding.
“So it is critically important to balance these emergency resources together with load shedding to ensure we manage the power system safely while keeping the stage of load shedding as low as possible,” he said.
Oberholzer acknowledged that running the diesel guzzling open cycle gas turbines extensively is not a long term option for the power utility with diesel costs running at about R700 000 per hour per turbine.
“[The open cycle gas turbines] were always intended to be used…early in the morning and late in the afternoon when there is a lot of demand on the country. So it was never designed that way, but unfortunately because of the system that is not performing the way it’s supposed to, we have to use it extensively.
“Between Ankerlig and Gourikwa [power stations], we are using nine million litres of diesel a day to support the system. We all agree that it’s not sustainable and we need to get out of this situation but this is where we find ourselves. For us, burning diesel and having a financial blood nose is much better than putting the country into a higher stage of load shedding,” he said.
He revealed that the electricity supplier is exploring alternatives which will mitigate the over reliance on diesel.
“We are looking – and we will go to the market very soon – to invite the supply of gas. We’ve already implemented the dual burners a few years ago on all our open cycle gas turbines. So we are looking at…moving over to gas, which is much cheaper,” he said.
Eskom Generation Executive Phillip Dukashe assured the public that “every trip, every load loss” at the power stations is investigated to improve performance.
“It’s been a very challenging period in generation. Some of these units that have failed have just come back from outages. You can imagine that people have been working very hard and they bring the unit back but there is no breather and that unit again needs attention.
“We have said that this year is going to be a hard year and it’s proving to be a very difficult year. One of the units that is more reliable…at Koeberg is on outage. Because it’s on outage and it’s a big unit, obviously the rest of the system feels it because we have to make up [for it]. Our coal-fired units tend to be much more unreliable than nuclear.
“But I can give the assurance that we are doing all we can to try and deal with the issues that we are facing at the moment,” Dukashe said.