The deal with Korea Zinc subsidiary Ark Energy would be the equivalent of about 25 per cent of Telstra’s electricity needs.

It also shows that Ark has shifted its intent from not just decarbonising the Sun Metals zinc operations in Townsville, but to move into the broader energy market.

Ark was also part of the announcement last month by a consortium to build a 3GW of renewable energy generation near Collinsville in central Queensland as part of plans to produce more than 1 million tonnes of green ammonia per annum for export by 2032.

Ark has a 30 per cent stake in the Macintyre wind farm, which was expected to be Australia’s largest when completed in 2025.

Ark chair Yun Choi said the deal was a milestone for the company while Telstra said it would help manage its costs. The deal is for 350GWh a year.

“At first I founded Ark Energy to decarbonise the Jorea Zinc group starting with Sun Metals, however as we have grown our renewable energy p[ortfolio s has our ambition to accelerate the energy transition more broadly by supporting other similar commercial and industrial scale businesses decarbonise their energy supply,” Choi said.

Telstra said it had now supported about $1 billion of renewable energy and now had about two thirds of its electricity demand generated through renewables. Its aim was for 100 per cent in by 2025.