A milestone in the development of offshore wind energy in the United States was reached with the launch of the nation’s first offshore floating wind turbine off the coast of Castine, Maine. 

Called the VolturnUS, the structure will also be the first offshore wind turbine that will be connected to the North American power grid.  The VolturnUS is a prototype–a  65-foot-tall floating structure that is one-eighth the scale of a commercial installation.  Floating turbines offer several advantages over offshore turbines that are fixed in place.  For example, they are able to operate in deeper waters where ocean wind speeds tend to be stronger and also can be kept out of sight of observers on the shore. 

DOE funding

The 5-year project to design, build, and launch the VolturnUS was led by the University of Maine’s (UM) Advanced Structures and Composites Center, which received assistance from the U.S. Department of Energy (DOE), including a     $12 million investment.  Other federal and state agencies, as well as more than 30 industry partners, were also involved.  The long-term goal of this and related projects is to reduce the cost of offshore wind to compete with other forms of electricity generation with no subsidies, says the UM.  

Maine has 156 gigawatts (GW) of offshore wind capacity within 50 miles of its shores and a plan to deploy 5 GW of offshore wind by 2030.  According to the UM, this plan could potentially attract $20 billion of private investment to the state, creating thousands of jobs.

Pioneering design

The DOE notes that the VolturnUS is the first concrete-composite floating platform wind turbine deployed in the world.  The structure has a “unique semi-submersible platform that uses a lower cost concrete foundation in addition to a lighter weight composite tower,” says the DOE.  The department gives credit to the Maine Maritime Academy, which helped test and conduct analyses on the “pioneering designs,” and Maine-based Cianbro Corporation, which leveraged its experience in maritime energy infrastructure and shipbuilding to construct the system.

The bulk of U.S. offshore wind capacity lies in deep waters where conventional turbine technology is not practical.  “Innovative floating offshore wind turbines like the one launched today will open up new economic and energy opportunities for the country,” says the DOE.  The UM adds that data acquired from the operation and performance of the VolturnUS during 2013 will be used to “de-risk” and optimize the design of the patent-pending system.

Seven new projects
Under a separate project, the UM is planning a 12 MW, $96 million offshore wind demonstration pilot farm called Aqua Ventus I.  That project is one of seven offshore wind design and engineering projects announced in 2012 by the DOE.  Upon completion of the engineering and design phases, the department intends to select up to three projects for additional funding in 2014 to support construction and installation.

Click here for information on DOE’s wind energy program, including VolturnUS.