A Moroccan concentrated solar power plant that is one of the largest in the world has been hit by a leak from a molten salts tank used to store excess green power that Saudi developer ACWA Power has said will result in losses of around $47m.

ACWA Power said last week that there had been a leak from its molten salts energy storage facility at the Noor-Ouarzazate Solar Complex in the Moroccan desert, reported at one point to be the largest concentrated solar facility in the world with around 580MW of capacity, enough to power a million homes.

The leak has affected the third stage of that project, Noor III, in which ACWA Power holds a 75% stake.

AWCA said it will now have to repair the tank and potentially build a new tank, with the forced outage likely to last until November.

The Saudi power company said the initial estimated revenue loss is around $47m.

The Ouarzazate solar complex is located less than six miles from the town of Ouarzazate, a city south of the High Atlas mountains in Morocco and known as a gateway to the Sahara desert.

The first phase of the project was commissioned in 2016 and the subsequent two phases came online several years later. The project received backing from the African Development Bank Group, European Investment Bank and other multilateral institutions.

The Noor III phase of the Ouarzazate complex captures energy by having huge mirrors that track the sun’s movement bounce its light and energy towards the tip of a 243-metre-high steel tower – taller than many skyscrapers – at their centre.

The energy captured can from there be transferred to huge containers filled with salts that are heated to hundreds of degrees Celsius and can store energy for up to seven hours, allowing it to discharge energy day and night.

Morocco has been trying to boost its renewables capacity to become more self-sufficient in its energy needs. At one time it was the largest energy importer in the Middle East and North Africa, importing over 97% of its energy.