CONCORD — The state’s highest court has pulled the plug on Northern Pass.

Supreme Court justices ruled unanimously to deny a request by project officials to order a state committee to reopen deliberations on the proposed $1.6 billion transmission power line, according to their ruling released Friday.

“The court has made it clear –- it is time to move on,” said Gov. Chris Sununu, a project supporter. “There are still many clean energy projects that lower electric rates to explore and develop for New Hampshire and the rest of New England.”

The state Site Evaluation Committee unanimously rejected the Northern Pass project in February 2018 and later turned aside a request to reconsider its decision and resume deliberations.

“We have reviewed the record and conclude that the subcommittee’s findings are supported by competent evidence and are not erroneous as a matter of law,” the 31-page ruling said.

Northern Pass officials “have not sustained their burden on appeal to show that the subcommittee’s order was unreasonable or unlawful,” Associate Justice Anna Barbara Hantz Marconi wrote.

Eversource, in a statement, said it was “deeply disappointed” with the decision.

“We will closely review the Supreme Court’s decision and evaluate all potential options for moving forward. It’s clear that the need for new energy sources in New England is greater than ever, and we remain focused on innovative solutions that will lower costs for our customers, improve reliability and advance clean energy.”

The 192-mile Northern Pass route would have run from Pittsburg to Deerfield through more than 30 communities, bringing hydropower from Quebec into New England.

After attorneys for both sides squared off before the Supreme Court on May 15, Eversource New Hampshire President Bill Quinlan said reapplying with a revised Northern Pass application was “certainly something we’d consider.”

The Society for the Protection of New Hampshire Forests, a foe of the project, applauded the unanimous decision and thanked those who opposed the project.

“We took on Northern Pass because we saw the proposed overhead line as a direct threat to conserved lands in the state, including three of our Forest Reservations and dozens of conservation easements,” said Jane Difley, president/forester of the Society for the Protection of New Hampshire Forests. “We want to thank all of those who invested a significant portion of their lives over the past nine years in hopes of this outcome.”

Added forest society attorney Amy Manzelli: “This legal victory is a win for everyone in New Hampshire and beyond that treasures New Hampshire’s superior landscape and outdoor recreation.”

The Appalachian Mountain Club said the Supreme Court delivered “a final, fatal blow to the proposal.”

“After nearly nine long years, we are thrilled to finally see this misconceived, poorly designed, outdated overhead transmission line proposal finally laid to rest,” President John Judge said.

All five justices concurred that the committee acted within the law.

“Our review is limited to determining whether the subcommittee’s findings are supported by competent evidence in the record and are not erroneous as a matter of law,” the decision said.

“In doing so, we defer to the subcommittee’s resolution of conflicts in the testimony and its determination of the credibility of witnesses and the weight to be given evidence,” the ruling said.

“We reiterate that it is not our task to reweigh the evidence or to determine whether we would have credited one expert over another,” the decision said.

State law requires the state Site Evaluation Committee to find a proposed project meets four criteria. The committee said the project had not met its burden to show the project would not “unduly interfere with the orderly development of the region.”

Northern Pass argued the state committee should have deliberated on all four criteria and should have suggested ways to limit or eliminate impacts in an effort to improve the project.

But the justices thought otherwise.

“To the extent the petitioners imply that the subcommittee itself is required to craft mitigation measures, we reject this position,” the decision said.

The SEC conducted 70 days of adjudicative hearings, heard testimony from 154 witnesses and received more than 2,000 exhibits.

Eversource spent $249 million on Northern Pass through September 2017, including engineering, property purchases, attorney fees and application fees. Eversource was funding the construction through borrowing and stockholder equity.