First U.S. Grid-Connected Offshore Wind Turbine Installed Off the Coast of Maine

This is an excerpt from the Third Quarter 2013 edition of the Wind Program R&D Newsletter.

Castine, Maine — On May 31, 2013, the University of Maine's Advanced Structures and Composites Center partnered with Maine Maritime Academy and Cianbro to launch a deepwater offshore floating wind turbine near Bangor. When the turbine was turned on and electricity began flowing through an undersea cable to Central Maine Power on June 13, the VolturnUS 1:8 became the first grid-connected, floating offshore wind turbine in the Americas.

The VolturnUS 1:8 is the culmination of more than 5 years of collaborative research and development conducted by the University of Maine-led DeepCwind Consortium, which is a public-private partnership funded by the U.S. Department of Energy (DOE), the National Science Foundation–Partnerships for Innovation, Maine Technology Institute, the State of Maine, and the University of Maine. More than 30 additional research and industry partners, including the DOE's National Renewable Energy Laboratory (NREL), contributed to the project.

The VolturnUS 1:8th-scale system employs a 65-foot-tall 20-kilowatt (kW) turbine with a 31.5-foot diameter rotor. This prototype will provide the University of Maine with the knowledge and experience needed to develop the full-scale VolturnUS, incorporating a 6-megawatt (MW) turbine with a 423-foot rotor. It was designed at the University of Maine, assembled at Cianbro's facility in Brewer, and is now anchored in Castine Harbor in 80 feet of water. The VolturnUS 1:8 is the second floating semisubmersible turbine support structure to be deployed in the world; plus, it uses a concrete platform instead of steel. Concrete could prove to have several advantages over traditional metal structures—one being cost.

Data acquired during the 2013 deployment will be used to optimize the design of the University of Maine's patent-pending VolturnUS system. The goal of the project is to reduce the cost of offshore wind to compete with other forms of electricity generation with no subsidies when the technology is scaled up to the commercial level.

In response to a 2010 congressional directive, DOE awarded federal funding to the University of Maine to perform research on and develop floating offshore wind turbine platforms. The primary objectives were to experimentally validate coupled aero-elastic/hydrodynamic computer models (i.e., computer models used for the design and optimization of a turbine and turbine platform system that predict structural loads, deflections, dynamics, and turbine power output under various meteorological and oceanographic conditions) developed by NREL and others for floating offshore wind turbines, and to better understand the dynamic response behavior of floating offshore wind systems.

Following this test deployment, the next step for the DeepCwind Consortium team is to build two 6-MW VolturnUS floating turbine systems to be moored off Monhegan Island in 2016. Design for these floating offshore wind platforms is currently underway, funded in part through a separate competitively-selected DOE Wind Program grant for advanced technology demonstrations for offshore wind.

Read more about the University of Maine project.