OCEANSIDE — The California Coastal Commission postponed a decision late Wednesday on a proposed 45-megawatt peaker power plant at Mandalay Beach in Oxnard, following nearly three hours of testimony and debate.

Several commissioners said they'd like to have additional information about its environmental impacts, and some said the beach is no place for the project.

The commission will continue the discussion at its October meeting in Ventura.

Wednesday's hearing in Oceanside was prompted by the city of Oxnard's denial of the project in July 2007. Southern California Edison appealed to the commission, hoping to get the decision reversed.

"Oxnard always seems to be a second-class citizen when it comes to coastal protection," said Commissioner Sara J. Wan.

"This area has miles of unbelievable coastal resources — beaches, dunes, wetlands ... we don't need another plant like this on the coast," she said.

She suggested that Edison ought to consider building the plant in Goleta.

An inland parcel near Goleta was one of five location finalists considered by Edison before the company settled on Mandalay Beach.

The Mandalay site, which is next to Reliant Energy's 430-megawatt plant, was chosen because it would be the least expensive and easiest to develop, Mark Nelson, Edison's director of generation planning, said in an interview outside the hearing.

Wan also questioned Edison's need to build a fifth peaker plant in Southern California, where four such facilities already have been built.

The California Public Utilities Commission directed the company to build "up to five plants," she said, adding that a fifth is not required.

Assemblywoman Julia Brownley, D-Santa Monica, submitted a letter to the commission requesting that it deny approval of the plant, or at least wait until the completion of a study by the California Public Utilities Commission, expected later this year.

The study "may put to rest the question of whether more peaker plants along the coast will be needed at all," she wrote.

David Kay, an Edison official, told the commission: "The peaking need is serious and continues to be serious."

The proposed plant is needed to provide power to western Ventura County and eastern Santa Barbara County in the event of a disaster, such as a big fire or a major earthquake, he said.

"We can't tolerate delay," Kay said. "We need that peaking capacity now."

Oxnard City Manager Ed Sotelo asked commissioners to "please consider our long-term vision and desires."

Building another power plant on Oxnard's coast would frustrate the city's desire to eventually remove all power plants from the coast, he said. The city would like to see the two existing power plants on its coast removed once they become obsolete and have them replaced by new facilities inland, he said.

Spokesmen for several Oxnard business groups testified in favor of the proposed plant.

"The business community needs reliable energy and this is what this project is all about," said Bill Buratto, president of the Ventura County Economic Development Association.

But Commissioner Ben Hueso said he found it "hard to believe" the project would have no significant impact on native plants and birds, as Edison maintains.

The proposed plant is "not the right policy, not only in terms of air quality, but in terms of global warming," he said.

Commissioner Steve Blank suggested Edison investigate whether it might be able to build a peaker plant inside the existing Reliant plant, which has an obsolete peaker plant inside it.

In addition to its ability to provide additional electricity during peak demand in the area, a new peaker plant is needed to help restart the Reliant plant in the event of a major blackout, according to Edison officials.

Commissioner Mike Reilly questioned Edison's decision to build its plant in an area that is in a 100-year flood plain.

"Isn't that a little risky?" he asked.

Although local officials have identified the site as being in a 100-year flood plain, the Federal Emergency Management Agency has not issued a new flood map certifying that, Kay replied. Oxnard Councilman John Zaragoza said after the hearing: "I'm very happy they heard our concerns and that the residents of Oxnard and Ventura County are going to be able to express their concerns at the October meeting."

Nelson said Edison has "a lot of information to review" but continues to believe it has "a strong case" for the plant.