Johannesburg - On Thursday 4 000MW, or 10%, of Eskom’s 40 000MW electricity-generation capacity was unavailable.
This was because of various problems that had arisen in the power grid.
Eskom spokesperson Hilary Joffe
said the problems included a 600MW generation unit at the Duvha power station close to Witbank that had been seriously damaged on Sunday night.
Repairs to this unit would take months and seriously strained the utility’s ability to meet peak-time power demand.
Apart from these problems, Eskom needed to take a 900MW Koeberg power station unit out of service at the beginning of March for essential fuel reloading, which could take more than 40 days.
The Duvha and Koeberg disruptions shortly ahead of winter will severely stress Eskom’s generation capacity.
The situation is under control but is becoming increasingly difficult to manage, said Joffe.
She added that 3 000MW was currently unavailable owing to planned maintenance.
The loss of the Duvha unit meant that from now on Eskom would be unable to do 600MW of its planned upkeep and maintenance work. The utility was currently doing less maintenance than it would ideally like to do, she said.
Joffe said many of the power stations were old and working harder than designed to do. They consequently required substantial upkeep but, with reserve margins under pressure, it was difficult to keep up with all the maintenance without further compromising security of supply.
She said that the problems that had arisen across the network on Thursday – other than at the Duvha unit – would be resolved by the end of the week.
The size of the problem of lost capacity because of network difficulties was rather unusual, she said.
Eskom had previously warned that the electricity network would be under severe pressure both this year and next year. The first new power station would start to deliver power only at the end of 2012.
Standard Bank economist Adriaan du Toit said the bank believed that sustainable electricity supply was again under rising stress.
He said Eskom’s electricity demand forecasts indicated that from the first week of March there would be a real risk of no reserve margin at peak periods. With demand returning to the 2007 levels, security of supply was again expected to be under strain.
Du Toit said the recession had diverted attention from South Africa’s electricity problems. But as GDP started to rise the cracks would become more visible, he said.
Eskom expected to have a margin of 10% for the next couple of years, while the minimum target was actually 15%. With a declining margin the power network would struggle.
The measures that Eskom had introduced to save electricity, said Du Toit, as well as rising electricity prices and poor-quality coal, placed an added burden on economic growth in South Africa.
But there was light at the end of the tunnel in terms of three new power stations – Medupi, Ingula and Kusile – which would start to generate electricity between 2012 and 2015.
But until these power stations started to deliver, growth in economic activity would be constrained by power outages.
Joffe said it was too early to know what had happened at Duvha. But the damage was covered by insurance and an investigation was under way.