The plant would have burnt waste wood. Energy developer Peel Energy said it would have produced enough energy to power 37,000 homes.
Salford City Council and campaign group Biofuel Watch registered objections. A petition with almost 5,000 signatures and more than 1,500 letters opposed to the scheme were also received.
Peel Energy project manager Jon England said: "We are disappointed that the planning committee has seen fit to turn down the expert evidence placed before it.
"The recommendation for approval was very clear. The proposal accords with national and local planning policy and a number of other similar proposals have gained planning consent elsewhere recently.
"We will now take some time to consider the findings of the committee’s official written report before deciding on our next course of action."