Mr. Fenzl said the company has not made a final decision to move ahead and was weighing commitments from other suppliers to use the facility, as well as potential government support. He estimated the cost of the project at 500 to 650 million euros . “For us, as Uniper, this is a lot of money,” he said. “It is not an easy task to get if off the ground.”

Building an L.N.G. terminal would not guarantee that Germany would import fuel from the United States. “The German stance is that they are going to take the most competitive L.N.G. supply that they can. If that happens to be the U.S., that is a bonus,” said Murray Douglas , an analyst at Wood Mackenzie , a market research firm.

Mr. Douglas said the United States would need to compete with Qatar, a major exporter, as well as planned projects in East Africa. Russia is also increasingly competing in the L.N.G. market.

Other German ports, including Stade, have also joined the competition for a terminal. In Brunsbuettel , the state-owned Dutch gas distributor and partners are considering a terminal in part to make up for lost supplies from the quake-rattled Groningen field. All three of these cities are near Hamburg, the thriving commercial and maritime hub in northern Germany.

Of course, local and environmental opposition to liquefied natural gas could grow, as it has in other ports. The Wadden Sea is considered a unique area of mud flats and shallows, and environmentalists say that putting a terminal there might cause pollution, while the big ships could damage the sea bottom.