The announcement was made today at the Windpower 2014 conference in Las Vegas by Dave Danielson, assistant secretary, Office of Energy Efficiency and Renewable Energy for the US Department of Energy (DOE).
"Offshore wind may become more competitive faster than you’d expect," Danielson told the conference.
The projects were selected from seven contenders that had already received $4 million each in funding under the DOE cost-sharing programme.
Fishermen’s 25MW demo Atlantic City project off New Jersey was a surprise choice.
It will use 5MW Chinese XEMC turbiines. But state electricity regulators recently declined to give it a permit, saying the cost was too risky for consumers in part because the turbines have no commercial operating history.
Fishermen’s is appealing the regulatory decision in court.
Dominion Virginia Power’s 12MW project, the Virginia Offshore Wind Technology Advancement Project or VOWTAP, will consist of two Alstom Haliade 6MW turbines.
Using US-designed substructures, it will be a distant 41km offshore from the mid-Atlantic coast.
Principle Power’s 30MW WindFloat will be sited near Oregon, in the deep Pacific Ocean.
It will feature Principle’s own semi-submersible floating foundations and five Siemens 6MW turbines in 366-metre waters.
Importantly, the three winners must meet rigorous deadlines, said Danielson. Ultimately, they must be online by 2017.
By the end of next year, they must have completed their design work, permitting and have an offtake agreement.
"If they do not [meet the deadline], there are the alternates," Danielson cautioned. "If a team cannot get an offtake agreement, then they will not go forward."
The two projects chosen as alternatives will receive research and development assistance from government laboratories.
They are the 27MW Icebreaker, by Lake Erie Energy Development Corporation (LEEDCo), the only fresh water project; and Aqua Ventus 1, a 12MW pilot by DeepCwind in the Atlantic Ocean off Maine and using floating turbines.
DeepCwind consists of Emera, Cianbro and Maine Prime Technologies.