Eskom CEO Tshediso Matona says plans are in place to ramp up output at the Majuba power station to a sustainable 1 800 MW for the coming six months, while the utility finalised interim and permanent recovery solutions for the 4 100 MW facility.

On Friday, the plant was producing around 1 600 MW from four of its six units, with one unit (Unit 4) down for a 90-day overhaul and another (Unit 3) offline until a coal-supply solution could be found to bring it into partial operation.

The immediate solution, which was still being optimised, was likely to be in place for six months, while Eskom finalised a phased plan to restore full output at the 4 100 MW plant. Full recovery was expected to take two years to implement at a cost yet to be determined.

Group executive for generation Thava Govender indicated that the interim solution would probably involve the construction of a temporary conveyor system to feed the coal from coal stockyard to power station units.

Output at the plant fell from around 3 600 MW on November 1 to 600 MW on November 2 following the collapse of its central coal silo, which led to a break in the coal handling systems carrying coal to the plant’s six units.

The catastrophic structural failure at the 4 100 MW facility led Eskom to institute its second load-shedding event of 2014 on November 2, which was also the second since the rolling blackouts of 2008.

Matona described the decision to shed load on that Sunday as a “deliberate choice”, designed to build reserves ahead of the business week so as to limit the economic impact of the power cuts.

The coal handling system at the plant – which is unique within the Eskom fleet – had not been designed for redundancy, which meant that neither of the other two silos nor their conveyors could operate in the absence of the central silo.

The Majuba plant team was, thus, forced to introduce a “complex” and potentially hazardous back-up coal-handling system based on large coal trucks, articulated dump trucks, bulldozers and mobile conveyors. The cost implications of this interim solution were still being calculated.

Matona described as “remarkable” the progress made since the collapse of the silo just after midday on Saturday November 1 and confirmed that group executive for capital projects Dan Marokane was leading a dedicated site recovery team.

In parallel with investigation into the silo’s failure, a detailed recovery plan, which would include designing and costing a replacement coal conveyer system and silo structure, would be undertaken. The redesigned solution should be finalised by the end of December, while the investigation could take between three to six months to complete.

Acting group executive for technology and commercial Matshela Koko indicated that the permanent solution would most likely be different from the previous design, noting that redundancy had been built into the coal-handling systems at all other Eskom power stations.

The power system, meanwhile, remained constrained but stable and group executive for sustainability Dr Steve Lennon said no load shedding was being forecast for the foreseeable future.

However, Majuba would be more vulnerable to wet weather and load shedding might not be avoidable should there be another major unforeseen disruption at any of its coal-fired power stations.

Govender said the combination of having much of its fleet in its midlife together with only a limited amount of additional new capacity, meant it was a battle to balance the system. However, he stressed that the organisation was far more resilient than had been the case in 2008.

There was a big focus on improving its electricity availability factor, which has fallen from around 90% at the turn of the century to 75% last year.

“We have now embarked on a programme, which we started about 18 months ago, to recover that availability. We have a programme that aims to [restore availability] to 85% and we have got another three to four years of that programme to run – and that is the maintenance programme we are talking about,” Lennon explained.

“It is not a quick fix, it is not easy and it takes a lot of courage, because when you are doing that in a very, very tight system then it means that you are going to have times when a major incident like this is going to push us over the edge,” he concluded.