Why Eskom stopped sharing peak power demand numbers

After more than a three-week hiatus, Eskom has resumed publishing evening peak electricity demand statistics on X/Twitter.

On Tuesday, 6 February 2024, the utility posted its first evening peak demand update since 16 January 2024.

That came a day after Eskom acknowledged a query from MyBroadband asking why it had stopped sharing these figures.

The posts provide information such as how much generation capacity Eskom had during moments of peak demand in the evenings and how much electricity it shed from the grid using load-shedding.

They also reveal how much power was contributed by renewable energy at peak demand and the number of open-cycle gas turbines (OCGTs) Eskom ran at peak.

The practice was started in 2022 by former Eskom spokesperson Sikonathi Mantshantsha, who posted the statistics daily on his personal Twitter profile from July 2021.

The updates were generally regarded as a positive step in the utility’s aim to be more transparent with the public about the performance of its generating fleet.

During Mantshantsha’s tenure, there were rarely any breaks in publishing these updates, and they were often posted on the same night as the applicable peak period or early the following morning.

Following the conclusion of his three-year contract in February 2023, Mantshantsha left the company.

Initially, the updates continued to be provided daily, albeit often a bit later than Mantshantsha’s updates, but they later became erratic.

The longest break in the updates started in the middle of January 2024 and continued in the first few days of February.

MyBroadband asked Eskom why it had stopped publishing the updates over the past few weeks.

It told MyBroadband it may sometimes not publish these statistics if it also issued a Power Alert.

These statements sometimes contain Eskom’s expected demand for the evening, but not how much electricity it actually cut from the grid during load-shedding, how much generating capacity it had available during the peak, or any of the other valuable information mentioned above.

Eskom said it was looking at other platforms where it could publish the evening peak demand statistics for those who found them valuable.

The utility also provides details on a wide range of performance metrics of its generating fleet on a public-facing dashboard launched in 2020.

However, some of this data is presented in a way that would be difficult to interpret by the general public.

Stage 7 and stage 8 load-shedding claims

Energy experts and the media have previously used Eskom’s evening peak statistics to call out the utility when it allegedly implemented higher levels of load-shedding than defined on its website.

This includes several occasions in early 2023 when Eskom appeared to have implemented stage 7 and stage 8 load-shedding.

Eskom often denied this but at one point acknowledged it had technically implemented stage 7 load-shedding.

The disparity between Eskom’s communicated stages and what the energy experts believed it had actually implemented could be attributed to Eskom’s definitions of load-shedding on its website being a gross oversimplification.

The website states that each load-shedding stage allows up to 1,000MW to be shed from the grid.

However, the NRS 048-09:2019 standards document governing the implementation of load-shedding explains that each stage of load-shedding allows for up to 5% of the total load at the point of implementation to be shed from the grid, up to 40% for stage 8 load-shedding.

Simply put, each stage of load-shedding could see between 1,200MW and 1,650MW cut from the grid, based on the load ranging between 24,000MW in the low-demand season and 33,000MW in the high-demand season.

The document also mentions the 1,000MW intervals per stage of load-shedding but explicitly regards these as “roughly” the amount of power cut from the grid.