The University of Maine had $12 million in investments from the U.S. Energy Department for the prototype project.
"The Castine offshore wind project represents a critical investment to ensure America leads in this fast-growing global industry, helping to bring tremendous untapped energy resources to market and create new jobs across the country," wind and wave Energy Director Jose Zayas said in a statement.
The U.S. Energy Department said offshore wind could eventually generate more than 4,000 gigawatts of electricity, four times what's produced for the entire grid currently.
The University of Maine's design used advanced concrete composites from a small-scale offshore wind energy platform.
There aren't any commercial-scale wind energy projects deployed offshore in the United States. The U.S. Interior Department in March said it was moving closer to issuing its first leases for offshore wind energy developments in the Atlantic Ocean.