State-owned power utility Eskom says it is unlikely that there will be any load-shedding over the next seven months as the utility’s generation performance starts to improve.

The embattled utility had managed to avoid load-shedding for 164 consecutive days, with an average energy availability factor of 70.4% as at the end of August, COO Jan Oberholzer said last week.

Eskom’s nine-point generation recovery plan is on track, yielding some positive results and sustaining a solid performance from the transmission and distribution networks, despite an increase in illegal connections, vandalism and equipment theft.

“There has been a significant contribution from both commercial and noncommercial units among the power stations,” added Eskom chairperson and acting group CEO Jabu Mabuza.

Addressing the media at the utility’s latest Status of the System briefing, he explained that three noncommercial units at Medupi and Kusile had delivered more 1 000 MWh in the past six months, with Kusile Unit 3 synchronised to the national grid on April 14 and Medupi Unit 3 having reached commercial operation on July 5.

Medupi’s Unit 1 was also synchronised to the grid on August 27.

This meant that, for the first time, all six Medupi units had been connected to the grid.

Further, the Cahora Bassa hydropower plant, in Mozambique, had been successfully restored, while 1 200 MW of imported renewable energy was added to the grid, and Kriel Unit 2 and Matla Unit 5 were returned to service, adding an aggregate 1 050 MW to the grid, said Oberholzer.

Generation unit breakdowns were maintained at below 9 500 MW for much of the winter period, and less diesel was used than planned, with year-to-date totals reaching R1.4-billion – well below the budgeted R5.4-billion.

“While winter showed positive results, our focus has now shifted to effectively dealing with the summer period,” Mabuza continues.

Eskom is planning for 5 500 MW of capacity to be maintained during the summer period and it will aim to keep unplanned plant breakdowns below 9 500 MW during the period to prevent load-shedding.

Demand for the period is expected to be about 30 000 MW.

However, Eskom outlines three possible unplanned breakdowns scenarios – 8 500 MW, 9 500 MW and 10 500 MW – saying these unplanned outages could trip the utility up and send the country into load-shedding.

Should Eskom maintain breakdown at below 9 500 MW, a minimum amount of diesel would be required to avoid load-shedding.

Breakdowns of between 9 500 MW and 10 500 MW would increase the risk of load-shedding, as well as the amount of diesel needed by the utility as it tries to avoid load-shedding.

Any unplanned breakdown in excess of 10 500 MW, however, would mean that load-shedding could no longer be ruled out and a high level of diesel use would be required to keep the lights on.

“The use of pumped-storage and open-cycle gas turbine diesel generation to supplement capacity is necessary, but consistent use could result in a rapid depletion of emergency resources, which could lead to load-shedding,” Oberholzer warned.

Full load losses, partial load losses, slips and major incidents have been the major contributors to an increase in unplanned losses.

The Kendal, Arnot, Tutuka, Medupi and Kriel power stations have contributed about 62% of the total partial load losses to date, with the main contributors being the draught plant, gas cleaning, milling plant, feed water and ash plant, accounting for 79% of the trips reported in the period to date.

Other risks that could lead to load-shedding, in addition to new trips and plant breakdowns, include high vacuum levels owing to high temperatures; delays in returning plant to service after a planned outage; any “macro factors” such as protests, adverse weather or strike action that could further impact on plant performance; excessive use of emergency resources, such as diesel and hydropower, for consecutive days; increased theft and vandalism; and severe weather conditions impacting on electricity imports.