The future of wind, most farsighted experts believe, lies offshore. And the future of offshore wind may be installations in deep waters, 20 to 50 miles out, floating like energy-generating ships at sea.

Deep water is defined as depths of over 300 feet. Eighty-three percent of the U.S.'s offshore wind resource is in deep water within 56 miles of the shore. The Department of Energy's ambition to get 20% of U.S. power from wind by 2030 will require 16% of that wind to come from offshore deepwater resources. Oceans of Opportunity, a 2009 paper from the European Wind Energy Association, predicted Europe would get almost half its electricity from deepwater offshore wind by mid-century.

There are Norwegian and Dutch sites for deepwater wind research operated by industry players. The DeepCwind Consortium National Research Program at the University of Maine is the first U.S.-based research program of its kind. It is unique both in that it specializes in deepwater wind and that it is a public institution that will make its findings publicly available.

The head of the new program is Dr. Habib J. Dagher, Director of the AWEC Advanced Structures and Composites Center at the University of Maine. Elizabeth Yvonne Viselli is Associate Program Manager.

Funded by the U.S. Department of Energy (DOE), the National Science Foundation-Partnerships for Innovation (NSF-PFI) and others and partnered with the National Renewable Energy Laboratory (NREL), the lab will test the full spectrum of hypothesized solutions to deepwater challenges in the Gulf of Maine with scale models in laboratory tanks during the fall of 2010. With the results of that test, the lab will test a one-third scale model in the summer of 2012.

This fall's tests will develop data on the three major turbine-base concepts: (1) The buoyancy stabilized platform, (2) the ballast stabilized turbine base and (3) the mooring line stabilized platform/spar hybrid concept. Viselli stressed that the base concepts have already proven themselves in the offshore oil & gas drilling industry and the turbines are the same proven machines used in the onshore wind industry. "But what happens when you couple a floating platform with a wind turbine?" she asked. NREL has developed models that couple them, but "until you validate them, they're really a video game," Viselli said.

The buoyancy-stabilized platform floats at the surface and is anchored to the seabed by mooring lines. With the ballast stabilized concept, a long cylindrical spar significantly wider in diameter than the turbine tower extends deep below the surface and is anchored to the seabed by mooring lines. The mooring line stabilized platform/spar hybrid concept uses a seabed-moored small platform floating just below the surface and a shorter spar extending from it

The concepts the lab will test this fall are different in two ways from those pioneered and proven in the offshore oil & gas drilling industry: (1) deepwater offshore wind projects have no known attendant environmental catastrophe potential and (2) to endure the ocean environment, they must conquer not only extreme wave (hydrodynamic) loads but -- because they rise like sails precariously high above the surface and could therefore tip backward and forward -- severe wind (aeroelastic) loads, as well. 

The lab is currently working with several turbine manufacturers, but the early experiments are designed to be "turbine agnostic."

This fall's tests will be conducted with yet-to-be-determined variations on the three basic designs. They will be composed of state-of-the-art durable, lighter, hybrid composite materials. In the summer of 2012, the lab will settle on a one-third scale turbine that is approximately 100 feet in height, chosen from the most successful of the tested models.

In the summer of 2013, the lab will partner with the patent holder of the most successful design to build a utility-scale (3-to-5 megawatt) floating deepwater turbine.

"Our goal for all of these deepwater technologies and what eventually gets commercialized," Viselli concluded, "will be 20 to 50 miles offshore, the reason being that Maine has a very vibrant commercial fishing industry that we don't want to interrupt. We also have a vibrant tourism industry. Those are two of the main industries in the state. We don't want to upset that balance."

At that distance from shore, there are also not likely to be aesthetic complaints. "After about 20 miles offshore, the horizon line, due to the curvature of the earth, begins to drop off, so you stop seeing those 3-to-5-megawatt wind turbines," Viselli said.

The lab will conduct thorough impact studies and monitoring and address potential entanglements, disturbances or interferences with marine mammals, birds, bats and fish, impacts on wave energy and social, aesthetic, historic, and cultural concerns.

It is no accident that the home chosen for the lab is a structures and materials center. The key to wind's future is not only in mechanical engineering, but in materials science as well. Why? Because the high cost of offshore wind is the main obstacle to its success. New direct drive turbine technology may already hold the solution to mechanical reliability. Better materials could be the key to resolving the durability part of the problem. (The implication is that the clever way to invest in the future of wind is to find out who makes direct drive turbines and the materials that will endure the harshest environments and invest in the processes and companies that make them.)

This laboratory represents the kind of federal support for research and development that renewable energy industry advocates have clamored for. With federally funded, technology-neutral, publicly available data, entrepreneurs can move ahead with proven technologies and not waste time and money on technologies that do not test successfully.

The final and perhaps most exciting aspect of the new laboratory is that, because it is part of a university, much of its workforce is composed of students. Viselli described student involvement as "huge."

"Our mission is really threefold: It's producing high quality research, commercializing the technologies that we research," she said, "and education...I have 12 or 13 undergrad and grad students who work on the offshore wind projects specifically." Other managers also supervise students. "They're a big part of everything we do," Viselli said.

The lab will also be a focal point for the development of undergraduate and graduate programs in wind at the University of Maine. When the students who work there obtain advanced degrees, they will move on to other academic positions where they will undertake advanced research and pass their hands-on experience to others, slowly growing a coterie of experts that can further drive U.S. offshore innovation.

 

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