Weak demand not only cause of falloff in load-shedding, Eskom insists

South Africa’s State-owned electricity utility Eskom insisted on Monday that the performance of its generation fleet was on an improving “trend”, rebuffing arguments that its newfound ability to avoid load-shedding was primarily the result of sharply lower demand from industry.

Speaking at a quarterly state of the system update, CEO Brian Molefe acknowledged there being “some truth” in arguments that demand had been lower in 2015 than during the previous two years. But he insisted this was only for periods, with the electricity demand profile having “remained relatively similar over the August to October period for the last three years”.

During that time, Eskom had resorted to only two hours and twenty minutes of load-shedding and Molefe indicated that the prognosis remained encouraging for the rest of summer and beyond, unless a confluence of unplanned events affected output, as had been the case ahead of the September 14 load-shedding incident.

Even the drought conditions were not expected to have an immediate negative impact on a group whose power stations rely heavily on both coal and water to produce electricity. Eskom said its dedicated dams were 58% full, while its power stations had coal stocks of 58.2 days on average.

Molefe’s assertions where met with a degree of scepticism, however, in light of few signs of a fundamental improvement in the utility’s energy availability factor (EAF) and given the weak production performance of key energy-intensive sectors such as manufacturing and mining.

A recovery in the EAF had been set as the main priority for Eskom by the Electricity War Room, which had indicated that the utility should be targeting availability of 80%, against a performance of below 75%. Eskom’s own ‘Generation Sustainability Strategy’ aimed to achieve 80% plant availability, 10% planned maintenance and 10% unplanned maintenance over the medium term.

Newly appointed group executive for generation Matshela Koko backed Molefe’s assertions, saying that, since the creation of the war room, load losses had fallen from around 8 000 MW to 5 800 MW currently.

He said the other main change since the adoption of a strategy to “perform maintenance without load-shedding” had been the setting of generation and planned maintenance budgets of 32 500 MW and 4 500 MW respectively.

SLOWER MAINTENANCE CATCH-UP

The idea, Molefe said, was to continuously fine-tune its maintenance programmes to claw back the maintenance backlog, without “doing maintenance at all costs”.

“So we will catch up with the backlog slower than we would have if we were doing maintenance at all costs, but we will catch up with the backlog anyway.”

Koko said that the EAF as of November 16 stood at 74.4%, with 33 000 MW of production balanced against 5 000 MW of planned maintenance and 5 800 MW of unplanned outages. The 33 000 MW was the highest level of output achieved in the past 18 months and came ahead of a scheduled outage of the infrastructure that facilitated the importation of 1 500 MW from Cahora Bassa, in Mozambique.

He noted that the EAF reported at the previous system update stood at 73% and that, as the EAF recovered, the use of the expensive open cycle gas turbines (OCGTs) would decline. Eskom was targeting OCGT load factors of around 5%; well below the 12% levels achieved during the sustained period of load-shedding in the first half of the 2015 calendar year.

In addition, the OCGT plants would be converted to operate as dual diesel/gas plants during their upcoming shutdowns, the first of which was planned for December. They would only be converted to operate as combined cycle gas plants once there was greater visibility of security of gas supply.