CARLSBAD - With little fanfare and a few short words of praise, Carlsbad's City Council unanimously approved a final version of a 30-year contract with Poseidon Resources to supply the city with desalinated seawater.

"I, for one, am very pleased," Mayor Bud Lewis said. "We've worked very hard on it."

Councilman Matt Hall said much of the praise should go to the mayor; "this thing is not an easy undertaking ... the job was well done."

The Connecticut-based company wants to build a plant capable of producing upward of 50 million gallons of drinking water a day. The proposed plant would go on a 4-acre site at the Encina Power Station along Agua Hedionda Lagoon.

Carlsbad only needs up to 25 million gallons of water a day, so Poseidon must obtain commitments from other water users to make the project a reality. The company has been talking with the San Diego County Water Authority for years about a joint project.

Those talks stalled earlier this year over site-access issues, and only restarted after Carlsbad began finalizing an agreement with Poseidon. Company officials have said that if they can't build a project with the Water Authority's participation, they will get water-purchase commitments from Oceanside and other Carlsbad neighbors.

Carlsbad officials have repeatedly said they think the project requires the participation of the county agency. Speaking after Tuesday's meeting, the city's lead negotiator on the Poseidon deal — city Administrative Services Director Jim Elliot — said that last week's Water Authority meeting gave him hope that those talks are now moving forward.

Peter MacLaggan, a Poseidon senior vice president who is handling the desalination plant project, said he believes it will be easier for the two parties to work together now that Carlsbad's agreement has been approved.

It can be a model, and will "take some uncertainty out of the occasion," he said.

For Carlsbad's part, it sought a deal that guaranteed it will pay no more than what the city's current water supplier — the county Water Authority — is charging at the time Poseidon's proposed plant opens.

That is scheduled to take place sometime in 2008.