The company plans to add two more turbine generators. If they survive, they are considering another stretch of water, where the current moves even faster, for an array that could hold up to 18 additional generator units.

When the whole project is done, projected for 2016, the array could power up to 1,500 homes, Mr. Sauer said.

This 1,322-person city, accessible only by hundred-mile ribbons of two-lane highways, has been waiting for years to become a renewable-energy laboratory.

“We’ve got deep water,” said Robert Peacock, the City Council president, who has lived in this region for much of his life. “That’s the best thing we’ve got.”

On a recent summer evening, Mr. Peacock, who is also a harbor pilot, and a power company official drank pisco sours with their wives on the deck behind his house, watching bald eagles nest and awaiting Sergio Versalovic, a marine energy specialist arriving from Chile to view the installation site. Chile is one of many foreign countries interested in how the Maine experiment might work in their own waters — Mr. Versalovic said the Straits of Magellan could be a good candidate.

The deep water of this coniferous coastline has already given the city’s port a steady stream of shipping traffic. But the effort to use it to produce energy has a choppy history, and for some residents the current project is unfolding in its shadow.