Eskom has blamed “electrical faults”, likely caused by mist, for knocking out five generating units at the Kriel power station on Monday and putting South Africa back on the brink of load shedding.

The state-owned utility said in a statement that the trips have knocked 2GW of generating capacity from the system. “The fault, which appears to be related to the heavy mist conditions experienced at the time, is under investigation,” it said.

“The first fault caused units 1, 2 and 3 of the power station to trip, while the second fault tripped units 4 and 5. Unit 6 was offline at the time.”

While some units are expected to return to service during the day on Monday, they will take time to reach full capacity. Any further loss of generators, or some units failing to return to service as anticipated, will likely trigger load shedding at short notice, Eskom said.