Load-shedding is crushing mobile Internet in South Africa

Load-shedding directly impacts mobile network infrastructure, and, as a result, mobile Internet speeds tend to suffer.

A MyBroadband analysis showed that Vodacom and Telkom customers saw the most significant drops in network performance during periods of load-shedding.

We compared average mobile data speeds during a load-shedding and unconstrained power period.

The data confirmed that mobile networks struggle to maintain performance during continued power outages.

We used tests done using the MyBroadband Speedtest app to compare two week-long periods.

We used MyBroadband Speedtest data from the week of 7–14 September 2022, during which South Africa experienced consistent power cuts.

We chose the period of 19 to 26 August 2022 — during which there were no significant power cuts — as a control.

The first thing that’s immediately clear is that users performed significantly fewer tests during load-shedding periods.

The most prominent case is on Telkom, where users performed 62% as many tests as usual during load-shedding.

While this may be due to users not having Internet access during bouts of load-shedding, this discrepancy could also be driven by users with larger data caps not having electricity for their home routers.

Rain and MTN did not see a substantial change in the number of tests performed. Rain actually recorded a slight increase in tests during the load-shedding period.

Across all five networks, subscribers performed 79% as many tests during load-shedding as during times of unrestricted power supply.

We also looked at the average speeds achieved during these periods to see how the experience changes for users who can still connect.

Cell C and Rain performed exceptionally, with speeds improving across the board during load-shedding.

This could be due to a significant portion of its customer base not having access during these times, reducing congestion on its network.

Rain also improved its average download speed and latency, but its average upload speed dropped slightly.

MTN remained surprisingly consistent throughout load-shedding, with its average download speed within 95% of the typical values and upload speed dropping to 90%. Latency improved slightly during load-shedding.

Vodacom and Telkom saw the worst degradation in download speeds and latency during rotational power cuts.

Their average download speeds dropped to 84% of the period without load-shedding, while latency was around 13% worse than usual.

The combined figures make it clear that although some operators manage to keep their networks together during extended power cuts, many users cannot access the Internet during these times, and those who can generally have a worse experience than usual.

Load-shedding between 7 and 14 September

For perspective, Eskom implemented all-day Stage 2 load-shedding from Wednesday, 7 September, and extended the schedule to implement rotational power cuts throughout the night on Thursday the same week.

The power utility attributed the power cuts to various generation unit breakdowns and a need to replenish its emergency reserves.

On Friday, 9 September, Eskom announced that it would increase load-shedding to Stage 3, running throughout the weekend until 05:00 on Monday, 12 September.

However, Stage 3 never made it as far as Monday, with the power utility upping rotational power cuts to Stage 4 on Saturday, 10 September.

Stage 4 load-shedding was in effect for the remainder of the testing period used for our comparison.

Notably, rotational power cuts have worsened since, reaching Stage 5 on Saturday, 17 September, and then Stage 6 the next day. Load-shedding is set to drop back to stage 5 at Tuesday midnight.

The results of our load-shedding network performance comparison are summarised in the table below.

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