A proposal for a wind turbine on the Bristol Downs has been put forward by a design and architecture company.
Stride Treglown said the turbine could power about 400 homes and that it wanted to stimulate a debate about making Bristol a greener city.
But the deputy Lord Mayor, Peter Abraham, who runs the Downs Committee, said: "It would be very large and dominant and not in keeping."
Planning permission has not yet been sought.
And no company has been lined up to build and run the proposed turbine.
A site at Peregrine Point, near Bristol Zoo, has been proposed for the turbine, which would also be a visitor attraction and help educate Bristolians about renewable energy, according to Stride Treglown.