A power failure that plunged most of Zambia into darkness on Monday was caused by a fault at a transformer in a substation in the north of the country, according to a copy of a letter from the biggest electricity supplier to mines.
Preliminary findings show that the error at the Kitwe substation tripped the remaining transformers, some of which were out of service for upgrading, according to the letter from Copperbelt Energy Corp. seen by Bloomberg News.
“The resultant situation led to the total loss of generation at Kafue Gorge and Kariba North Bank power stations,” which are the countries biggest power plants, Copperbelt Energy said.
A spokeswoman for the company wasn’t immediately able to verify the contents of the letter when contacted by phone.
The power cuts that lasted until Tuesday afternoon could cost mining companies four days’ worth of output and the economy more than $50 million in lost productivity. The failure also led to blackouts in large parts of Zimbabwe, knocking out hydro-electric and thermal plants in the neighboring country.
Zesco Ltd., Zambia’s state-owned power company that supplies Copperbelt Energy, has been undertaking rolling blackouts as it struggles to meet demand.
Construction of the Itezhi Tezhi hydropower project and Maamba coal-fired power station that would help boost capacity have been delayed.