Five foundations are set after an inaugural construction season for what will become the first commercial offshore U.S. wind farm, developers said.

Deepwater Wind, one of the developers behind the Block Island wind farm off the coast of Rhode Island, said five steel platforms are now installed.

The project should yield 30 megawatts of electric power, powering the 17,000 homes on Block Island, 12 miles from the mainland, that currently use diesel fuel for electricity. Excess electricity will be carried to the mainland by cable.

The turbines will be 589 feet above sea level, making them among the tallest in the world. While the plan is small in comparison to many land-based wind farms in the United States, Deepwater Wind could demonstrate the feasibility of using offshore wind as an energy option. Offshore wind already generates 8,760 megawatts of power in Europe and Asia.

"Rhode Island is proud to be home to the nation's first offshore wind farm, and we're quickly becoming a center of innovation in this growing industry," Rhode Island Gov. Gina Raimondo said in a statement.

The Rhode Island government in May 2014 signed off on environmental permits for the wind farm.

Wind energy development up and down the New England coast has been met with opposition from preservationists worried about the potential threat to coastal habitats and aesthetics.

Deepwater Wind Chief Executive Officer Jeffrey Grybowski said work on the offshore wind farm was done "while upholding very high environmental standards."

Deepwater Wind and its partners at GE are working on critical electrical components for the project from a facility onshore. Cable installation is set to begin in early 2016 with the aim of power generation during the latter half of next year.