SAINT JOHN, New Brunswick — Canada’s first liquefied natural gas terminal officially opened Thursday in this coastal community after years of opposition. Officials supporting the project were already talking about a potential expansion.

Repsol and Irving Oil partnered on the $1 billion LNG terminal, which will supply natural gas by pipeline to the northeast United States.

The huge terminal on the shores of the Bay of Fundy is the first of its kind to be built on the East Coast of North America in 30 years.

“Together we share in celebrating an amazing achievement — the official opening of one of the most important energy facilities ever built on the East Coast of North America,” Antonio Brufau, chairman and CEO of Repsol, said at a ceremony to commission the facility.

Meanwhile, interested observers in Maine, where similar projects have been proposed on Passamaquoddy Bay in Washington County, reacted with a mix of appreciation and concern.

Harold Clossey, executive director of the Sunrise County Economic Development Council, said that the proposals in Maine, including that of Down East LNG in Robbinston, are being affected by a natural gas market that is at, or near, an all time low.

“Who can say now what the effect of the Canaport LNG project will be? This can affect the U.S. companies competitiveness,” he said.

Robert Godfrey of Eastport, speaking on behalf of the Save Passamaquoddy Bay 3-Nation Alliance, said Thursday the Canaport facility stands in stark contrast to the Maine proposals.

“Canaport had the good business sense to site their facility at an industry-compliant location five miles east of Saint John,” Godfrey said. “They selected a site where navigational challenges for LNG carriers and passing traffic and where conflicting uses, environmental impacts, and impacts on civilians, are at a minimum.”

In contrast, Godfrey said, “LNG developers in Passamaquoddy Bay selected eminently inappropriate locations according to best practices established by the LNG industry itself. The outcome being celebrated today exemplifies the differences between Canaport and the proposed Passamaquoddy Bay projects.”

A call to Down East LNG headquarters reached an answering machine. No message was returned.

With a deep-water, ice-free port and a modern jetty, the Canaport terminal can receive LNG tankers year-round. Liquefied gas is stored in three large storage tanks, each covering an area the size of a football field. The liquefied gas is then heated, expanding to 600 times its original volume.

The facility is capable of shipping more than a billion cubic feet of natural gas every day — enough to heat and power 5 million homes — through a pipeline to the U.S. border.

Irving spokesman Daniel Goodwin said while there’s no crystal ball for natural gas prices, officials are already thinking about the future of the plant. “If the markets were to grow, if the opportunities were to arise, we could expand this plant,” he said.

The terminal is a fixture in plans by New Brunswick Premier Shawn Graham to make the province a major player in the region’s energy future. “What a great day to be standing at the center of New Brunswick’s energy hub,” Graham told the crowd that filled a tent, which was set on a clearing for possible future storage tanks.

Bangor Daily News writer Sharon Kiley Mack contributed to this report.