The loss of utility partners and a damaging court ruling in Massachusetts apparently have failed to kill the $3 billion Access Northeast natural gas pipeline project, which proponents consider critical to lowering power costs in Maine and New England and environmental groups have been fighting hard to defeat.

Houston-based Spectra Energy said Wednesday that it will move ahead with Access Northeast despite a setback in the Bay State, the region’s largest energy user. Spectra has estimated the project would save New England consumers $1 billion a year.

“New England is at a pivotal moment in determining its energy future, and the ‘do nothing’ scenario is untenable,” Arthur Diestel, director of stakeholder outreach for Spectra Energy, said in a statement to the Portland Press Herald. “Without targeted expansion of natural gas pipeline capacity, New England energy consumers will inevitably bear the brunt of ever-increasing energy prices and ever-diminishing supply reliability.”

Spectra’s affirmation is of special interest in Maine. Over the objection of environmental groups, the Maine Public Utilities Commission last month gave conditional approval to a plan in which electric customers would help subsidize the construction of private natural gas pipelines. Access Northeast was the larger of two proposed projects approved for consideration.

But Access Northeast appeared to be on its deathbed earlier this week.

Spectra’s two utility partners told state regulators in Massachusetts on Monday that they were pulling out of the project. Eversource Energy and National Grid cited last week’s Supreme Judicial Court ruling in Massachusetts, which prohibited ratepayers from financing private pipeline projects.

The ruling was in response to a lawsuit from plaintiffs that included the Conservation Law Foundation. The environmental group, which has an office in Portland, favors renewable energy sources and efficiency measures over expanding fossil fuel use, to counter climate change and air pollution.

But Diestel stressed that the action taken by Eversource and National Grid only involves Massachusetts. The utility partners remain committed to seeking approvals in Connecticut, Rhode Island and New Hampshire, he said, where Access Northeast also would be located. More than 95 percent of the project would use existing pipeline and utility corridors.

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Massachusetts, however, uses nearly half of the electricity in the region. Spectra has said each state would pay a proportional share of the project cost.

Two large liquefied natural gas tanks that would store fuel also were planned for Southeast Massachusetts. A primary site in Acushnet and an alternative in Somerset have been identified.

Diestel declined to answer questions about how Spectra would proceed in Massachusetts and whether it might have to find new locations for LNG storage in southern New England.

“We’re evaluating our path forward in Massachusetts,” he said. “We’re confident we will be able to continue forward.”

Access Northeast is designed to upgrade the existing Algonquin Gas Transmission pipeline through southern New England and add LNG storage. The goal is to bring more gas capacity to serve the region’s power plants on the coldest winter days, when electricity demand and wholesale energy prices peak.

Gas is used to generate roughly half the region’s electricity. In the winter, New England burns roughly 4.5 billion cubic feet of gas daily. For comparison, that’s equal to about 31 million gallons of heating oil.

But the Conservation Law Foundation and other interest groups want to wean New England off gas, not increase dependence. It has intervened in each of the four states where Access Northeast would be developed. It also has asked the Maine PUC to reopen its proceeding, based on what has happened in Massachusetts.

“The project is likely dead,” said Greg Cunningham, director of the foundation’s Clean Energy and Climate Change program. “But it is at least different, and that difference will require new contracts, new filings and new approvals, if not new business plans and business partners and investors.”

Cunningham acknowledged that the Massachusetts court ruling doesn’t set a legal precedent in other states, but he expects it will have an impact.

“Its finding certainly has persuasive value in every New England state, as the states all have very similar restructuring laws and each has the paramount goal of protecting ratepayers,” he said.

Spectra is making progress with two smaller pipeline projects in New England, one of which is only months away from completion.

The Algonquin Incremental Market project is on target to be in service this November. Spectra also is moving forward with Atlantic Bridge. The company hopes to have permits from federal energy regulators this fall, and be in service for the 2017-2018 heating season, a spokeswoman said.

But Access Northeast has become a focal point in the battle over natural gas expansion in New England.

It has taken on a new significance since last spring when Kinder Morgan, the nation’s largest energy infrastructure company, announced it was giving up on its Northeast Energy Direct pipeline proposal. The $3 billion project would have expanded the company’s Tennessee Gas Pipeline through Massachusetts and southern New Hampshire, bringing up to 1.2 billion cubic feet of shale gas from fields in Pennsylvania. It was one of three projects bidding to supply capacity to Maine, in the case before the PUC.

Northeast Energy Direct would have run 430 miles and created new pipeline corridors. Business interests and some consumer advocates voiced support for the promise of lower power bills. But environmental groups across New England, landowners along the proposed route and many politicians rallied against it, citing concerns ranging from the impacts of hydraulic fracturing during gas extraction to continued reliance on fossil fuels.

Tony Buxton, a Portland lawyer who represented Kinder Morgan and lobbies for industrial customers, said Spectra’s persistence is good news for New England consumers.

“The Massachusetts court decision,” he said, “doesn’t change the reality that year in and year out, New England consumers pay up to $3 billion in excessive electricity costs solely because we have inadequate pipeline capacity to provide both gas for heating and some gas for power generation.”