As winter approached in South Africa, Eskom would be relying on its customers to use less of its product and be more energy efficient to improve the reserve margin, which would allow for more flexibility of maintenance.

The peak forecast for 2011 was about 37 500 MW, which was a 2% increase on the 2010 peak demand.

“Our resolve will be tested,” said Eskom CEO Brian Dames at a quarterly briefing on the utility’s status of operations on Friday.

Public Enterprises Minister Malusi Gigaba said that Eskom faced a challenge during the maintenance season to mid-May 2011. “There is not enough of a window to do the necessary levels of maintenance to ensure that the winter peak electricity demand can be sustained,” he added.

Eskom said it needed 2 000 MW of operating reserve. However, with increasing demand, the low reserve margin has made it difficult to create space to shut down units for maintenance, raising the risk that units will fail, said Dames.

Eskom’s ideal maintenance ratio was about 10% yearly, including major repairs and routine maintenance work. The schedule for the current financial year included only 7% of planned maintenance.

Eskom said it expected a colder winter in 2011, than in 2010, and noted that for every degree decrease in temperature, electricity demand increased by between 600 MW and 700 MW during the evening peak.

As the utility approached winter, the amount of planned maintenance dropped. In January, 4 000 MW worth of generation capacity was under maintenance, while 3 000 MW was under maintenance in February, and 3 200 MW in March.

Adding to the increased pressure on the system was the failure of the Duhva power station unit 4, which would take a year to repair, and left a gap of 575 MW in the system.

Koeberg nuclear power station’s unit 2 was also currently undergoing planned refurbishment and refuelling before the winter peak period.

There were no planned power outages scheduled after mid-May, and only Duhva unit 4 would be out of service during winter.

“We are managing a tight power system. We are on alert, and will be for the next five, and especially the next two years, while we build new capacity,” Dames stated.

“Energy efficiency is crucial to ensure there is enough capacity to meet demand as well as to undertake essential maintenance and provide a reserve to protect the system,” he added.

The utility is spending some R1,8-billion on energy efficiency initiatives through its integrated demand management division, and has a target of saving 311 MW in the current financial year.

As Dames regaled energy saving tips to briefing participants, he urged all South Africans to participate in the 49M energy saving campaign, as the forthcoming tight supply situation would require that behavioural changes be made by all stakeholders.

Eskom has also signed up 373 MW in the medium-term power purchase programme, through agreements with Sasol for 240 MW, Sappi for 35 MW, Ipsa for 13 MW, and Tangent Mining for 85 MW.

Dames further stated that Eskom was supporting certain municipalities to run their own generation plant, and some 410 MW has been signed up, with 260 MW operational in the last month.

Negotiations were also under way to extend these agreements.

Eskom was still proposing that a mandatory energy conservation scheme may be required as a last resort to prevent disruptive load shedding, should the utility’s top 500 customers not voluntarily reduce electricity consumption.

This would likely entail penalties being imposed if targets were not met. Implementation of a mandatory scheme would, however be a government decision, coming from the Department of Energy.