Engineering News Online
written by Henry Lazenby

State-owned power utility Eskom was sticking to its warning on Wednesday that there may be a 9 TWh shortfall in electricity supply during 2012, despite a far lower-than-expected recovery in electricity demand, owing to the slowed recovery of the domestic economy.

Speaking at an ‘Action for Energy’ conference of The South African National Energy Association (Sanea) Eskom system operator GM Robbie van Heerden said that South Africa’s energy demand growth was currently trending at 2007 levels, growing only 1.5% on 2010.

In unveiling the Medium-Term Budget Policy Statement (MTBPS) in Cape Town on Tuesday, Finance Minister Pravin Gordhan officially lowered the country’s gross domestic product growth forecast for 2011 to 3.1%, from 3.4% announced in the 2011 Budget in February. Further, growth was now projected to reach only 3.4% next year, 4.1% in 2013 and 4.3% in 2014 – well below the 6% to 7% levels viewed as necessary to begin dealing with South Africa’s serious unemployment rate.

Analysts are becoming increasingly wary of the utility overstating the seriousness of the supply crisis, raising concerns that decreased investor confidence and foreign direct investment in new industries as a result of the power supply crisis, may create a demand side crisis.

This may result in the country mimicking the massively over specified electricity supply situation of the 1980s.

Van Heerden said that Eskom expected a supply shortfall of 6 TWh for this year, while the situation should start to ease by 2013 to a 3 TWh shortfall, a 2 TWh by 2014 and a 1 TWh shortfall by 2015.

The reduced shortfalls were expected on the back of independent power producers coming on line, Eskom increasing its generation capacity through new-build projects and small generation improvements at existing stations, cogeneration plants at industrial sites and backup generators.

The utility is also pushing ahead with its demand-side management levers, such as urging industry to participate in voluntarily energy-saving campaigns, running residential energy demand management campaigns, implementing cogeneration and own electricity generation schemes, employing renewable sources of energy, municipal generation and generation performance enhancement to reduce this year’s 6 TWh supply gap to 2.9 TWh.

Meanwhile, Eskom said it is struggling to keep up with its maintenance schedule, owing to the average age of the plants being 30 years and more.

Generation division executive Thava Govender said Eskom is dealing with an inability to provide constant base load power, owing to significant daily variations in the availability of its old fossil-fueled generators. Despite this, Eskom maintained only a 6.3% generator unavailability during 2010.

“While peer reviews rate us on par with other electricity suppliers in the world, there has been a declining trend in our score, underlining the maintenance and reliability challenges we face,” he said.

“The ideal would be to undertake 10% maintenance in a year, however, owing to the utility needing to supply peak demand electricity, which in 2011 peaked at 37 065 MW, generators need to be taken out of scheduled maintenance to provide the required electricity,” he said.

Further, the actual maintenance backlog is expected to increase, with only 8% maintenance to be undertaken this year and 6% in 2012. In 2014 only 5.5% maintenance would be undertaken, in anticipation of the new-build projects coming on line.

Govender explained that Eskom at all times required a net power provision of 3 500 MW more than the actual energy demand, owing to Eskom’s system operator requiring a safety margin of 2 000 MW of power, and the utility reserving about 1 500 MW for partial losses incurred as a result of long distance power transmission and the quality of coal it receives to burn at its power stations.

He pointed out that in an effort to reduce the maintenance backlog, Eskom was resorting to shutting down plants whenever possible to undertake maintenance at short notice. It was also working on weekends, when demand was lower, while the bulk of maintenance was usually undertaken over November, December and January, which were the months with the lowest energy demand.