OAKLEY -- After years of approvals, rejections and appeals for a 586-megawatt natural gas-fired power plant project, proponents are now in the driver's seat.

But groups opposed to the Oakley Generating Station haven't turned out the lights out on efforts to prevent its construction.

The Utility Reform Network filed a petition last week with the state appeals court to reverse the Public Utilities Commission's December approval of the Pacific Gas & Electric Co. power plant. The consumer advocacy group argues there is no conclusive need for new generation and "PG&E customers would be saddled with the costs of a billion dollar generation plant."

"The PUC needs to play by its own rules and not just act as a rubber stamp for PG&E," said Mindy Spatt, the group's communications director.

According to the petition, the commission relied on hearsay evidence to support its decision, as PG&E chose to use an analysis prepared by the California Independent Systems Operator for another project.

The independent systems operator did not testify regarding its analysis.

PG&E officials reiterated last week that the state-of-the-art Oakley plant supports the state's drive toward more efficient, environmentally friendly power sources.

"The Oakley project is at the right place at the right time," PG&E spokeswoman Tamar Sarkissian said.

The filing is the latest development in the long battle over the plant planned for 22 acres of industrial property on Bridgehead Road near the Antioch Bridge. It also marks the second time the state court has been asked to turn back a commission decision.

In March 2012, the appellate court annulled the Public Utilities Commission's December 2010 approval of the plant, saying the commission acted unlawfully in its hasty approval. PG&E revised its application, leading to December's approval by the PUC and the latest challenge.

First explored in 2008, Pacific Gas & Electric submitted applications a year later with the two state regulatory agencies for power plants -- the public utilities and energy commissions.

The energy commission gave the project the go-ahead in May 2011.

Oakley Mayor Kevin Romick expressed his frustration last week upon hearing about the latest legal challenge.

Officials see the plant as a spark for the local economy, as it is expected to create more than 700 jobs and bring millions of dollars into the community.

"We had heard that it was coming, so it wasn't a surprise," Romick said.

"But it's still frustrating. It's just one more delay in what has been a long, long struggle to get this approved." If approved, Danville-based Radback Energy will build the plant and sell it to PG&E once it is up and running. PG&E aims to bring the plant online by 2016.

Aside from some minimal grading work, no construction has been done at the site to this point.

Contact Paul Burgarino at 925-779-7164. Follow him at Twitter.com/paulburgarino.

Power PLANT Timeline
Last week's filing with the state appeals court is the latest development in Pacific Gas & Electric's years-long effort to build a power plant in Oakley.
Here is a timeline:
2008 -- Pacific Gas & Electric and Radback Energy begin exploring putting a natural gas-powered plant on the former DuPont site.
June 30, 2009 -- Application filed with the California Energy Commission.
Nov. 2009 -- First public hearing held by the California Energy Commission at the site; review of the plant application continues.
March 2010 -- Oakley officials pledge their support for the plant.
July 2010 -- The California Public Utilities Commission denies PG&E's application for the plant, citing falling state energy demand.
Oct. 2010 -- PG&E resubmits application with the PUC, moving back the date the plant would start operating from 2014 to 2016.
Dec. 2010 -- The PUC approves PG&E's revised application.
June 2011 -- The Utility Reform Network, or TURN, asks the state appeals court to overturn the commission's approval.
May 2011 -- The California Energy Commission approves the Oakley Generating Station.
March 2012 -- The California First District Court of Appeal annuls the PUC's approval, saying the board acted in haste when granting its approval.
April 2012 -- PG&E submits a new application with the PUC.
December 2012 -- The PUC approves PG&E's resubmitted application.
April 2013 -- State Public Utilities Commission rejects TURN's request for a rehearing.
May 2013 -- TURN asks the state appeals court to set aside the commission's decision.