The City of Melbourne is moving to secure long-term electricity supply from renewable sources.
The council says it will pool its energy demand with neighbouring councils, plus Federation Square and other major users, to jointly seek a long-term renewable supply.
That amounts to around 100 GWh worth of energy - which could be supplied by around 250,000 solar panels or 15 wind turbines.
"We hope this scale of demand will stimulate investment in a new renewable energy project that is shovel-ready and has planning approvals in place," Lord Mayor Robert Doyle said.
The City of Melbourne has a goal to produce zero net carbon emissions by 2020.