The court cited a previous ruling in a separate case that found hearings and orders could be tainted by comments that constitute prejudgment on the part of a member of the state Public Regulation Commission.
After issuing the warning, Chief Justice Barbara Vigil said that on appeal, the merits of the entire case would be reviewed under "a heightened level of scrutiny."
"We find the issues raised in the petition are important concerns of this court," she said.
At issue were allegations leveled by the environmental group New Energy Economy that four of the five members of the Public Regulation Commission created at least an appearance of being biased through public statements regarding a plan to shutter part of the San Juan Generating Station.
The court's decision to deny the petition without prejudice was unanimous with regard to all of the commissioners except Lyons. In his case, Justice Petra Jimenez Maes dissented based on comments the commissioner made about the case just weeks ago.
The ruling means the power plant case can move forward.
A final decision from a hearing officer is expected in the coming weeks. It will then be up to the commissioners to issue a final order on whether to approve plans by Public Service Co. of New Mexico to close two units at the power plant as part of an effort to meet federal standards for haze-causing pollution.
The plant's future has been the subject of much debate in recent years.
New Energy Economy contends PNM, which operates the plant, should replace the lost capacity with more renewable energy or shut down the entire plant to save ratepayers from future pollution regulations and cleanup costs.
PNM argues that keeping two units running and replacing the power with a mix of coal, natural gas, nuclear and solar would be more economical for ratepayers.
Mariel Nanasi, executive director of New Energy Economy, said she was pleased the court would be taking a closer look at the issue of prejudgment.
"The door is still open. That's what the message was," she said following Monday's hearing.
John Boyd, an attorney for the group had argued that commissioners should be held to the same standards as judges when they're making decisions. With the case involving the San Juan Generating Station, he suggested the commissioners identified the decision-making process as a political process and thus compromised due process.
Attorneys for the commissioners argued against removing them from the process, saying any concerns by opponents could be weighed during an appeal. Some called the allegations against their clients "insubstantial."
The justices did ask attorneys about commissioners balancing their role as quasi-government officials with their duty to constituents.
Commissioner Sandy Jones said state statutes are clear on what commissioners can and can't do.
"I think most of us know where that line is," he said.