Darkness descends — Eskom confirms blackout in Zambia and Zimbabwe after ‘incident’

At around 12.55 on Tuesday afternoon, the lights flickered and then failed across Zimbabwe and Zambia. This synchronised blackout, the second in recent weeks, was triggered by cascading failures in the Southern African Power Pool (SAPP) — a cooperative framework meant to bolster regional energy resilience.

Towards the end of November, another such blackout occurred which was attributed to “an unexpected development on the Zambia-Zimbabwe interconnector”.

The National Transmission Company of South Africa (NTCSA) — a wholly owned subsidiary of Eskom — told Daily Maverick that Tuesday’s incident was not a “power surge”, but rather an “incident, event or fault”.

“The tripping of lines occurs automatically to protect the power system and power equipment, and it is misleading to suggest that Eskom took a decision to disconnect the SAPP region.”



SAPP SADC grid map. (Source: SAPP)

While this measure prevented potential damage within South Africa, it intensified cascading failures that left Zimbabwe and Zambia powerless. The incidents occurred when the lines between Mozambique, South Africa, Botswana, Zambia and Zimbabwe tripped.

The Zimbabwe Electricity Transmission and Distribution Company (ZETDC) said an “imbalance in power on the international connections” caused the blackout.

In a statement, the ZETDC said, “[Zimbabwe Electricity Supply] Holdings would like to advise its valued customers that the national grid experienced a system disturbance which resulted in a national blackout on Tuesday, December 17, 2024, at 1255 hours. This incident was caused by an imbalance in power on the international connections which affected the national grid of Zimbabwe and some parts of the region.

“Restoration to most parts of the country has been completed, except for areas under load shedding.”

The incident is being investigated by the SAPP Coordination Centre based in Harare.

The Lusaka Times reported that on Monday, a day before the blackout, Zimbabwe's power generation plummeted to its lowest level in more than 12 months, with daily electricity production hitting 736MW. For context, just one of Koeberg Nuclear Power Station’s two units can produce 970MW.

Eskom is Africa’s largest electricity producer, supplying nearly 30% of the continent’s power. Accordingly, it plays a critical role in the SAPP.

Complementing this is the NTCSA, which operates under a National Energy Regulator of South Africa-issued licence which allows the NTCSA to manage imports, exports and the trade of electricity within the SAPP, ensuring the interconnected grid functions smoothly and efficiently. DM