Gloucestershire County Council has spent more than £3.3m in the last five years on a waste incinerator project its planning committee then refused permission for.
The figure was obtained via a Freedom of Information request by the BBC.
Ian Mawdsley, the council officer who has overseen the project, said they had tried to keep costs down.
The decision to refuse permission will be looked at by a government planning inspector later this year.
The council signed a 25-year contract to build the facility at Javelin Park, in Haresfield, last year.
But in March its planning committee unanimously refused permission.
Mr Mawdsley said the process to find a solution to burying waste in the ground had been the biggest procurement process in the council's history.
He said: "The average [cost] for a project is around 2.5% of its capital value for external advisors, so for this project it would be about £5m.
"Our cost, including external and internal advisors, is around £3m.
"Some of it goes to run the internal team like me, my deputy, my technical officers, and some of the accountants, lawyers and technical experts. It's all very carefully spent."
He added that the project had not taken longer than it should have.
"It does take this long, it is about the norm. It takes this long because we started with 11 proposals and eights bidders. We've had to whittle that down to the final one," he said.
The BBC also obtained a copy of the multi-million pound contract the authority signed with Urbaser Balfour Beatty to run and build the facility.
But some information, including details of any penalty clause should the council have to tear up the contract and look at other technologies, was withheld.
Mr Mawdsley said: "What we are trying to achieve is a balance where we give the public as much information as we possibly can without compromising the commercial position of the contractor who is obviously bidding for other work.
"The bottom line is we think we've got a good deal and the contractor probably doesn't want to disclose that to other people.
"If we were seen to be a council who released every confidential piece of information we got, we would never run a successful tender ever again."