CALGARY -- TransCanada won't be getting a regulatory decision on its Energy East pipeline any time soon.

The National Energy Board panel tasked with reviewing the $15.7-billion project decided Friday to throw out nearly two years of decisions made by the previous panel, which stepped down after concerns about a potential conflict of interest.

The board said all hearing steps and related deadlines for the TransCanada (TSX:TRP) project no longer apply as it begins to determine a new list of issues, list of participants and new process for reviewing the application.

"After much thought and consideration, we feel that re-starting the Energy East and Eastern Mainline hearings with a clean slate is the best course of action," NEB spokesman Marc Drolet said in an email.

"We understand there have been process missteps in the past, and that our decision may be an inconvenience to some."

The previous Energy East pipeline panel, which had been reviewing the project since TransCanada submitted its application in October 2014, stepped down last September after concerns were raised about a potential perception of bias after members met privately with Jean Charest while he was a paid TransCanada consultant.

A new panel was appointed earlier this month, with all three members committing not to speak with any members of the previous panel to avoid any real or perceived conflict of interest.

Much has changed in the pipeline world since the last panel stepped down, including federal approvals of Kinder Morgan's Trans Mountain and Enbridge's Line 3 pipeline projects, while the election and recent actions of U.S. President Donald Trump have opened the potential for TransCanada's Keystone XL to go ahead.

"From the perspective of how much supply we have in the basin and how much potential pipeline capacity we have, things have changed quite dramatically," said Jackie Forrest, vice-president of energy research at ARC Financial Corp.

She said there's still the potential for Energy East, with its 900,000 barrels a day of committed shipments, to go ahead, even if there was excess capacity.

"That's the old way of thinking, that supply must equal pipeline capacity. Really what Canadian industry needs is access to new markets," Forrest said.

TransCanada spokesman Tim Duboyce said they will be reviewing the NEB's decision to understand its impact on the project and the company, but similarly said the project remains important.

"Energy East remains of critical strategic importance because it will end the need for refineries in Quebec and New Brunswick to import hundreds of thousands of barrels of foreign oil every day, while improving overseas market access for Canadian oil," said Duboyce in an email.

TransCanada isn't starting entirely from scratch, with the NEB saying the company does not need to refile the more than 30,000-page application it submitted after 18 months of public consultations.

The new panel will, however, have to decide if the application is complete, and only then will the 21-month countdown start again.

Those who have already submitted an application to participate in the review process also don't need to reapply. The new panel will review all of the filed applications and release a new list of participants.

Environmental groups cheered the decision Friday, but were quick to say any further hearings should be put on hold until the NEB completes its review of its pipeline assessment process.

"For the new review of Energy East to be credible, the process cannot be restarted until the reform of the National Energy Board and Canada's environmental assessment laws is complete," Environmental Defence's Patrick DeRochie said in a statement.

"The federal government admitted that the current process is broken and appointed an expert panel to modernize the NEB."

He said the Energy East review should include a climate test to show whether projects fit with Canada's climate commitments.

The review panel will examine a proposed 4,500-kilometre pipeline that would carry 1.1-million barrels of crude oil per day from Alberta and Saskatchewan to refineries in Eastern Canada and a marine terminal in New Brunswick.

The board says the previous panel's decisions have also been rendered void for TransCanada's 279-kilometre Eastern Mainline natural gas pipeline application, which was submitted along with Energy East because some existing gas pipeline will be converted to oil under the Energy East plan.