Johannesburg - A technical fault at South Africa's only nuclear power plant has cut close to 1 000 MW of electricity from the already strained power grid and is potentially exposing the country to more rolling blackouts.

“Unit 1 of the Koeberg power station is currently out of service due to a technical fault on the main generator transformer at the power station, which resulted in the unit being isolated from the national grid,” the utility said in a statement.

The cash-strapped company implemented power cuts for three consecutive days last week to try to prevent the national grid from being overwhelmed as demand threatens to outstrip capacity.

Koeberg, in the Western Cape, has two units, which each feed 930 MW to the national grid, which needs about 30 000 MW to meet daily consumption needs.

“At this stage, we can't say if there will be power cuts from tomorrow. We are hoping that other units that were undergoing maintenance could come online,” said Eskom spokesman Khulu Phasiwe.