Contact Energy and Meridian Energy are looking to build the world's first large-scale green hydrogen plant in Southland.
A report for the two companies says a plant is feasible once electricity currently used by Tiwai Point aluminium smelter comes free.
The smelter has a supply agreement with Meridian through to late 2024. One sceptic is University of Canterbury professor in mechanical engineering,
Susan Krumdieck. She says producing green hydrogen is a waste of time and money.
Krumdieck also says a better use of surplus electricity would be to electrify rail and road transport.
Contact's chief executive Mike Fuge spoke to Corin Dann.
