Plans to install underwater turbines to generate power from currents in the St. Lawrence River have been pushed back until August.

Originally, two test "dummy" turbines were going to be put in place in April outside Cornwall, Ontario, but the Ontario Ministry of Transportation requested that the company, Verdant Power Canada, delay plans to accommodate a 30-day public comment period.

Migratory fish populations in late spring and early summer have extended that delay until August.

"Because this has never been done before, Transportation wanted a public comment period," said Trey Taylor, Verdant's president. "So the first phase has been stretched out."

The first phase includes the dummy turbines and environmental studies to be done before and after the turbines have been installed in the river.

Once the studies have been completed, with the help of officials from the Akwesasne Mohawk Reservation, real turbines will be installed in the river. They will be installed in groups that will generate approximately 5 megawatts of energy each. Verdant officials estimate that the currents in the St. Lawrence River outside of Cornwall will generate 15 megawatts, enough to power 1,100 houses.

Verdant has a similar power project in the East River in New York City, where the company is based. Those turbines, however, are less advanced than the ones that will be put in the St. Lawrence. Because of the difference in the projects, Verdant officials are taking the extra time before the dummy turbines are installed in the St. Lawrence to study the potential environmental effects.

"We're all still walking around kicking the tires on this one," Mr. Taylor said. "We're getting off to a slower start and getting the process worked out here."

The project will not affect shipping along the river because boats with deeper drafts are sent to the Seaway, which is south of where the turbines will be. The turbines will sit 10 feet under the surface of the water and be marked by buoys to warn recreational boaters.

Eventually, underwater turbines may spread to other parts of the St. Lawrence, Mr. Taylor said.

"We thought we'd try to get it right on the Canadian side and then possibly bring it over," he said.