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'Load shedding blew it for Eskom'



Thabiso Thakali, Saturday Star, Johannesburg, 3 May 2008



In the wake of Eskom's unexpected about-turn in suspending load shedding indefinitely, experts in the field have questioned whether the practice may have been counterproductive in the first place.

There were strong suggestions this week that load shedding had impacted unfavourably on Eskom's infrastructure, and this was why it had to be reviewed.

Experts warned that the country's ageing substations were not coping with load shedding, and that to continue could result in an even worse crisis.

Some electrical engineers suggested that recent substation explosions were indicative of the greater difficulties Eskom could face if it had not stopped the practice.

"Switching on and off poses a serious risk and threatens the lifespan of any piece of electrical equipment, and this can add to the likelihood of failure," said Joburg-based engineer Rob Melaia.

Dennis van Es, a mechanical engineer with the Energy Research Unit at the University of Cape Town, said while a report by the National Energy Regulator had indicated that transformers and distribution equipment were badly maintained in various municipalities, load shedding could have exacerbated the problem.

"The equipment could now be in a poorer state because of the switching on and off frequently. This could mean that the equipment would require a major overhaul at the time when it is expected to provide electricity," he added.

Technicians have also argued that, instead of saving the required 10% on electricity usage, load shedding was achieving the opposite - where businesses and residents increased their electricity usage during those times when electricity was available.

Eskom first introduced pre-emptive load shedding on April 1 and said it would run until July as a move to stabilise the power grid. It was aimed at cutting demand by 3 000 megawatts, and this was to be followed by four months of rationing power - but that could all change now.

"Oil-based circuit-breakers can get contaminated with carbon dioxide during load shedding and this can lead to an explosion when the power comes back on," warned Thys Botha, a Joburg electrical engineer. "You cannot use circuit breakers like operating switches; they were not designed to do that."

Hendrik Schmidt, the Democratic Alliance's spokesperson on energy, said he had learnt that the sudden decision to suspend load shedding was owing to its negative impact on the economy and Eskom's own infrastructure.

"Talk behind the scenes is that load shedding has led to massive destruction of infrastructure, which is why it had to be canned, subject to a review, for now." Schmidt said that for Eskom to suggest a 10% target of consumption reduction was close to being achieved was strange, considering that pre-emptive load shedding had lasted only three weeks.

Eskom has maintained that it was not aware of any failure of equipment directly linked to load shedding, but it admitted there was a probability that certain components of its infrastructure may require maintenance.

"Certainly load shedding can put stress on that equipment and increase a need for its maintenance. However, we will have to await a technical report on the incidents that involved explosions to be able to ascertain this," said Eskom spokesperson Andrew Etzinger.

He added that load shedding was never Eskom's preferred option because it was not good for the economy and the utility. He said the decision to suspend load shedding until further notice was taken by the management of the utility after seeing a considerable saving from various municipalities.

"On our distribution system we have installed large meters which measure municipalities' savings, and after realising a 5 to 8% consumption reduction, we took a decision to suspend pre-emptive load shedding."

Just a month ago they said this was the only way to survive


· March 26 – Eskom says householders are still using too much electricity and therefore announces it will start with pre-emptive load shedding on March 31 to achieve the required 10% savings on electricity consumption.
· March 31 – Eskom does an about-turn despite numerous advertisements telling customers about the start of pre-emptive load shedding. Eskom spokesperson says: “The outlook is far better than we anticipated.”
· April 1 – Eskom starts with pre-emptive load shedding. Eskom CEO Jacob Maroga says: “Due to the state of the system yesterday, we were able to accommodate this delay.”
· April 2 – Maroga downplays hopes of Eskom increasing its electricity reserves quickly thereby halting load shedding but instead, he says, reducing consumptionis the only quick fix. “If we only rely on supply (increases), the numbers are not looking good for many years,” he warns.
· April 19 – Walmer sub-station in PE explodes after power was restored following load shedding.
· April 22 – A Kempton Park sub-station catches fire following power outs leaving residents without power for a week. Bheki Khumalo, the department of minerals and energy spokesperson, says that there are no plans to scrap load shedding until the energy-saving target is met. “It’s the best way of conserving energy under the circumstances. It will keep our system running. It will ensure predictability. That’s why there’s a massive campaign to get everybody to know exactly where load shedding will happen.”
· April 30 – Eskom suddenly announces it has suspended scheduled load shedding. Maroga says: “We are seeing evidence of increased savings from municipalities and Eskom is optimistic that further reductions to reach 10% savings target are possible… We have said from the beginning that load shedding is not our preferred option to achieve the 10% [power] savings the nation needs.”

From: http://www.thestar.co.za/index.php?fArticleId=4384301

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