The head of the country’s green bank says the fine details of its role in the transition of the Tomago aluminium smelter’s electricity supply from black to green is still being worked out, underlining the amount of work that still needs to be done to unlock the $10 billion in new investment needed.

The federal and state government announced this week an agreement to provide $2.5 billion in funding to ensure the future of the country’s biggest electricity consumer as its long standing coal contract ends in 2028, and then transitions to a 100 per cent renewable energy supply by 2033.

Few details of the plan have been released, and the media statements issued by prime minister Anthony Albanese and NSW premier Chris Minns did not even mention the key roles to be played by the federal government owned Snowy Hydro and its green bank, the Clean Energy Finance Corp.

It was, however, confirmed by federal energy and climate minister Chris Bowen.

“We worked on a very innovative arrangement together with New South Wales, working with our government agencies, Clean Energy Finance Corporation and Snowy Hydro, to bring on that renewable energy,” Bowen said at a media event at Tomago on Wednesday.