Load-shedding warning as Eskom performance declines

Eskom’s energy availability factor (EAF) declined significantly over the last year, which is behind the increased load-shedding.

The EAF shows the percentage of time the power station was available for use when it was needed. It is a core measure of performance for any power utility.

Energy analyst Chris Yelland revealed that the EAF for week 34 in 2023 was 55.32%, much lower than the same period in 2022 when it was 61.10%.

The EAF for the 2023 calendar year-to-date is 54.52%, compared to 59.78% for the same period in 2022.

Eskom’s 30 power stations have 47,145MW of generation capacity. It includes 39,456MW from coal-fired stations, 1,854MW nuclear, 2,724MW pumped storage, and 2,409MW OCGTs.

Electricity minister Kgosientsho Ramokgopa said that one per cent of EAF equates to roughly 500MW of generation capacity.

Therefore, the 5% annual decline in the energy availability factor equates to two and three states of load-shedding.

The chart below, courtesy of Chris Yelland and EE Business Intelligence, shows the decline in Eskom’s EAF over the last three years.

The National Treasury data

The National Treasury also warned that Eskom’s energy availability factor continues to decline steadily and is significantly worse than its targets for this year.

The Treasury said Eskom’s EAF was reported as 54.49% as of 30 June 2023, signifying a decrease from earlier this year, which was recorded as 56.03% in March 2023.

The Treasury said that Eskom’s EAF “continues to decline steadily and is significantly worse than the proposed target of 65%”.

This decline was attributed mainly to an increase in unplanned losses (UCLF) to 34.97%, compared to 31.92% in March 2023.

During Q1, Eskom’s average unplanned unavailability was 16,718 MW – higher than the Winter Plan’s base-case assumption of 15,000 MW.

This resulted in load-shedding ranging from stage 2 to stage 6 on 91 days during the quarter.

The Treasury said Eskom continues to experience an increase in partial and full load losses, contributing significantly to the high UCLF.

Coal-fired stations recorded an average energy utilisation factor (EUF) of 96.27% for the period, with EUF recorded at over 90% at all 14 coal-fired stations.

This is substantially above the international norm, which is expected to average around 75%, considering the age of Eskom’s fleet.

This means that Eskom runs its coal-fired power plants very hard, preventing proper maintenance. This will cause increased breakdowns in future.

Curiously, Electricity Minister Kgosientsho Ramokgopa said Eskom was steadily approaching its target of achieving a 70% EAF.

Yelland said the government is misleading South Africans by claiming that Eskom’s energy availability factor (EAF) is nearing 70%.

“The government’s messaging that the energy availability factor is heading upwards and is close to 70% is just not true,” he said.


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