Opponents of the plan to build a new 128-megawatt, gas-fired power plant in New Orleans East have filed a lawsuit in Civil District Court seeking to block the project. 

They asked the court to put a hold on the suit until the New Orleans City Council decides whether to honor their request to reconsider the plan. 

But in the meantime they are making a case that the council violated the opponents' due process rights in failing to seriously consider alternatives to the proposed plant, which Entergy New Orleans has said would cost about $210 million.

The suit was assigned to Judge Piper Griffin.  

Plaintiffs in the case include the Alliance for Affordable Energy, the Sierra Club, the Deep South Center for Environmental Justice and 350-New Orleans, four groups that have spent nearly two years protesting the idea of a new power plant. 

“The right of New Orleanians to have a fair process was denied in the council’s decision to approve Entergy’s gas plant,” said Monique Harden, an attorney for Deep South.

“The council has a chance to get this right by reversing its decision, removing ... biased advisers from decision making, and examining critical evidence that shows that Entergy’s gas plant is not needed and will harm New Orleans.”

Entergy officials have argued that the city needs to replace the aging Michoud power plant that it decommissioned in 2016. They say the new plant would serve as a necessary backup source of power and that available alternatives would not produce enough power.

The company's critics have argued instead for upgrading transmission lines, using renewable energy sources and reducing demand through conservation. 

They claim the plant will be harmful to the health of nearby residents and to the environment.

The council, on the advice of its energy consultants, sided with Entergy last month, citing in particular the need for an energy source that can supply a significant portion of the city's power needs should a hurricane or other emergency knock out transmission lines bringing in power from other places. 

The lawsuit takes aim not only at council members but also their consultants, accusing them of performing “the conflicting roles of advocate and fact-finder” in advising the council to approve the plant.

The consultants — the international law firm Dentons US, the local law firm Wilkerson & Associates and Legends Consulting Limited of Denver — have stressed the need for a "quick-start" energy source in New Orleans.

The lawsuit also resurrects claims that the council should have included specific language in its approval of the plant to protect ratepayers from financial risks and that the plant poses environmental and social-justice concerns.

The city had not filed a response to the lawsuit as of Tuesday.

Two of the groups that oppose the plant, 350-New Orleans and the Alliance for Affordable Energy, have also threatened to sue the council for allegedly violating the open meetings law during the meeting at which its Utility Committee endorsed the plant in February. 

Council President and Utility Committee Chairman Jason Williams has disputed that allegation, noting that the council allowed everyone present the opportunity to address it during the eight-hour meeting. 

Follow Jessica Williams on Twitter, @jwilliamsNOLA​.