A council has revealed key details about a controversial contract for a £500m incinerator.
Campaigners wanted to know the cost of burning waste at the Javelin Park facility, and the potential profits from electricity generated there.
In June the information commissioner ruled the authority should release the information, but the council refused.
Now Gloucestershire County Council has revealed it will cost £112 per tonne to burn the waste.
The authority said this represented "value for money" as it was almost 20% cheaper than sending it to landfill.
However campaigners have argued it does not represent good value, and said the council has not compared the cost to other "non-landfill alternatives".
Gloucestershire County Council signed a contract with Urbaser Balfour Beatty (UBB) for the scheme near junction 12 of the M5 at Gloucester in 2013.
Earlier this year the council was told it must reveal some parts of a previously redacted report, released under Freedom of Information rules, which the authority had previously said was "commercially sensitive".
The council said a report by Ernst and Young found the authority will pay a net £112.47 per tonne over the 25 year lifetime of the project.
Campaigner Tim Davies said: "Far from proving the value for money of this project, these documents show there are still major questions to be answered."
He said one of the questions was "why no assessments took place to look at non-landfill alternatives and create at least some sort of competitive pressure at the time of renegotiation".
Work on the project began in 2016 and the incinerator is due to begin operating in July next year.
When the plans were first proposed the council said the incinerator would save local taxpayers £100m over 25 years and power 25,000 homes.