Labour council leader Richard Williams admitted while it was a good idea it was too expensive for the cash strapped authority which faces a £42m budget deficit over the next two years.
He blamed the Government for refusing to remove the legal hurdles so it could be held side-by-side with the police commissioner elections instead of in separate polling stations, pushing up costs.
Campaigners fighting the proposed plant at the city's western docks argued the estimated £75,000 cost of holding a so-called “preferendum” later this year would be better spent fighting a planning application.
No Southampton Biomass said its members wanted the council to spend the money more “wisely” on getting expert legal advice on the planning process.
Opposition Tories said the referendum had become a vanity project for the Labour administration.
Councillors this afternoon debated whether or not to continue with the planned vote on the question: “Do you support the current proposals by Helius Energy for a 100-megawatt biomass power plant on the Western Docks?”It would not be legally binding.”
Helius said its proposed biomasss power plant, which could generate enough electricity to power 200,000 homes, is needed to help cut the country's carbon emissions.
It would burn up to 800,000 tonnes of wood fuel each year, mostly shipped in through the docks from abroad.
Helius said it intends to submit a planning application by the end of the year.